Perspectives on Childhood Obesity Prevention:
Recommendations from Public Health Research and Practice
The Johns Hopkins Center for a Livable Future
Bloomberg School of Public Health
615 N. Wolfe Street, E2150
Baltimore, MD 21205-2179
www.jhsph.edu/clf
410.502.7578
About the Johns Hopkins Center for a Livable Future
Founded in 1996, the Johns Hopkins Center for a Livable Future promotes research and communicates
information about the complex interrelationships among diet, food production, the natural environment and
human health. As an interdisciplinary center it serves as a resource to solve problems that threaten the health
of the public and hinder our ability to sustain life for future generations.
About the Bloomberg School’s Department of Health, Behavior and Society
The Department of Health, Behavior and Society was established in 2005 with a mission dedicated to
research and training that advances scientific understanding of the impact on health of behavior and the
societal context.
Document prepared by:
The Johns Hopkins Center for a Livable Future and The Department of Health, Behavior and Society
Melissa Gilkey
Acknowledgements:
The authors would like to thank Robert S. Lawrence, Roni Neff, Sara Bleich, Shawn McKenzie, David Holtgrave, and Anne Palmer for their helpful review comments. Any errors contained in this document are the
sole responsibility of the authors.
Winter 2007
Table of Contents
I.
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . II. Background: Describing the Burden of Obesity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . III. Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Develop intermediate measures to better evaluate prevention programs. . . . . . . . . . . . . . . . . . . . . . . . Spotlight: Leslie Lytle, PhD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . IV. The School Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Provide at least 30 minutes of moderate to vigorous physical activity. . . . . . . . . . . . . . . . . . . . . . . . . . • Encourage the consumption of healthy foods by increasing the number of
healthy options and pricing them competitively. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Provide high-quality health education in areas such as nutrition and physical fitness. . . . . . . . . . . . . . . . Spotlight: Benjamin Caballero, MD, PhD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . V. The Built Environment and Neighborhood Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Make communities more walk-able and bike-able. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Increase access to healthy foods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spotlight: Penny Gordon-Larsen, PhD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VI. Marketing, Industry, and Public Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Advocate for regulation of youth marketing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Strengthen consumers’ ability to make informed food choices, access appropriate and
accurate information, and take an active role in influencing food policy. . . . . . . . . . . . . . . . . . . . . . . . . . . Spotlight: David Wallinga, MD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VII. The Ethnicity Gap and Cultural Contexts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • Engage local governments and community groups, particularly those most affected
by obesity, in community and policy interventions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spotlight: Shiriki Kumanyika, PhD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . VIII. Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix I: Reports Reviewed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Appendix II: Key Informants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Winter 2007
2
3
6
6
8
9
9
9
10
11
12
12
12
13
14
14
15
15
16
16
17
18
19
23
23
I. Introduction
In less than a decade the issue of childhood obesity has
become a leading public health concern in the U.S. In
part, obesity’s new prominence is the result of its increasing prevalence. Data indicate the condition is widespread
and ever-growing for Americans across many socio­demographic categories including children and adolescents1 (Wang & Beydoun, 2007). Obesity has often been
described as a crisis of epidemic, and even pandemic,
proportions (Kimm & Obarzanek, 2002), and is projected to affect almost one in four American children by
2015 (Wang & Beydoun, 2007).
Obesity is complex and controversial. Despite extensive
debate in scientific and lay communities, no single reason
has been found to explain why obesity rates have risen
so dramatically, nor has an agreement been reached as to
how to reverse these trends. With most to lose in terms
of years of life, children and adolescents are prominent in
obesity discussions, which are particularly fraught in light
of the fact that obesity-related behaviors such as eating
and physical activity are inextricably linked to the broader
cultural and social contexts of parenting, schooling, and
policymaking. Increasingly, obesity is understood as a
societal and environmental problem, rather than a purely
individual or moral one, but researchers are still uncertain
about which factors within the vast causal web are most
important and changeable. Against this backdrop, interest
in and funding for obesity-related research has increased
in recent years, with the National Institutes of Health
(NIH), for example, supporting over 270 child-specific
obesity projects over the last five years (Huang & Horlick,
2007) and the Robert Wood Johnson Foundation awarding over $40 million in obesity-related grants in 2006
alone (RWJF, 2007).
In absence of an easy cure, obesity researchers from
all backgrounds have stressed prevention. Biomedical
scientists, for example, have sought to better understand
metabolic mechanisms associated with childhood obe-
sity, while social scientists and prevention specialists have
highlighted the importance of health behavior and education, lifestyle factors, psychosocial contexts, and the built
environment, among other areas. Each focus has offered
a particular perspective on obesity in children, and each
has resulted in a different set of preliminary recommendations and suggestions for continued work. Although most
scientists agree that a multi-pronged, ecological approach
is needed for effective prevention, the sheer number
and diversity of recommendations make it challenging
to select the best intervention for a particular situation.
Nevertheless, given the stakes involved, public health
researchers and practitioners must press forward with
prevention efforts, following the Institute of Medicine’s
dictate to act on the “best available evidence—as opposed
to waiting for the best possible evidence” (2005, p. 3).
This report identifies areas of growing consensus regarding recommendations for childhood obesity prevention
by leaders in the public health community. It was inspired
by a 2006–2007 seminar series at the Johns Hopkins
Bloomberg School of Public Health organized and
sponsored jointly by the School’s Department of Health,
Behavior and Society and the Center for a Livable Future.
Based on interviews with experts featured in the seminar
and prominent reports on childhood obesity (see Appendices I and II). This paper identifies promising areas of
action in key social arenas: the school environment, the
built environment, policymaking, and ethnic and cultural
contexts. Recommendations related to issues of measurement are also discussed. In addition, leading researchers
in obesity prevention are highlighted throughout the
report in order to introduce various individual perspectives on the topic. By taking a look at childhood obesity
prevention research and interventions to date, this report
aims to help public health researchers and practitioners
gain insight into its particular challenges and opportunities for investigation and implementation.
Because much of the research related to the issue of childhood obesity is school-based, this report considers both children and adolescents
under the age of 18 with an emphasis on those of elementary- and middle-school age.
1
Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
II. Background: Describing the Burden of Childhood
Obesity Prevalence
Childhood obesity has captured national headlines due to
the astounding rate at which its prevalence is increasing.
Beginning in the 1970s, obesity rates among children and
adolescents began to rise sharply and have yet to level off.
The percentage of obese 2- to19- year-olds, as defined
by the 95th percentile for body mass index (BMI) by
age (see “Defining Obesity”), has more than doubled in
the past 30 years and quadrupled among adolescents of
certain ethnic minorities (Ebbeling, Pawlak & Ludwig,
2002). Data from the National Health and Nutrition
Examination Survey (NHANES) illustrate this trend
(Table 1) (Figure 1). The high rates of obesity are of concern because, contrary to popular belief, children do not
typically “outgrow” their weight status; most obese adolescents go on to become obese adults (Gordon-Larsen,
Adair, Nelson & Popkin, 2004).
Table 1: What percentage of children in the U.S. are obese?
(CDC, Overweight prevalence, 2007)
Year
Age
1971-1974
2003-2004
Percent Change
2-5 years
5.0%
13.9%
+8.9%
6-11 years
4.0%
18.8%
+14.8%
12-19 years
6.1%
17.4%
+11.3%
Figure 1: How has childhood obesity changed over time?
20%
15%
10%
5%
0
1971-74
1976-80
2-5 year olds
1988-94
1999-00
6-11 year olds
2001-02
2003-04
12-19 year olds
Source: Centers for Disease Control, Prevalence of overweight among children and adolescents
Winter 2007
Defining Obesity
Debates surrounding childhood obesity
extend even to its definition. In adult populations, body mass index (BMI), as calculated
by weight in kilograms divided by the square
of height in meters, is the most common
measure of the condition. A BMI of 18.5 to
24.9 is considered healthy, while a score of 25
to 29.9 is classified as overweight, 30 to 34.9 is
obese, and 35 and above is morbidly obese.
In children and adolescents, BMI scores are
not interpreted alone, but are considered in
terms of percentiles by age and sex in order
to better account for growth patterns. Some
public health authorities define childhood
obesity as a score at or above the 95th
percentile for BMI by age, while overweight is
used to describe the 85th to 95th percentiles.
However, others, including the Centers for
Disease Control and Prevention (CDC),
prefer not to use the term obese in regard
to children in order to acknowledge the
shortcomings of BMI as a pediatric measure;
these practitioners describe children at and
above the 95th percentile as overweight, and
those between the 85th and 95th percentiles
as at risk for overweight (CDC, Defining
Overweight and Obesity, 2007). This report
uses the former classifications of obese and
overweight with a more extensive discussion
of BMI and its limitations provided in
subsequent sections.
Health Effects
Illness. Childhood obesity was once framed primarily
in terms of its long-term consequences. In particular,
researchers emphasized that the condition was associated with increased risk of cardiovascular disease, type II
diabetes, and some cancers later in life. Today, however,
experts know that childhood obesity has more immediate
effects as well:
• Type II diabetes, once virtually unknown in children,
now accounts for up to 45 percent of all new pediatric
diabetes cases and is more often found in obese youth
(Fagot-Campagna, Pettitt, Engelgau, Burrows, Geiss,
Valdez, et al., 2000). Estimating the prevalence of
type II diabetes in children is difficult given low levels
of surveillance and variations across sub-populations.
However, using adult-specific data, the first estimates
of lifetime risk for diabetes were recently calculated
to suggest that the disease will eventually affect 33
percent of boys and 39 percent of girls among children
born in 2000 if current trends continue (Narayan,
Boyle, Thompson, Sorensen & Williamson, 2003).
• Adolescents and younger children suffer psychological and social effects related to obesity. Obese teens
are more likely to have poor self-image and low body
satisfaction (Strauss & Pollack, 2003) and experience
weight-related teasing. This teasing has been linked to
symptoms of depression, including thoughts of suicide,
for male and female adolescents in varying degrees
across ethnic groups (Eisenberg, Neumark-Sztainer, &
Story, 2003).
• Obesity in youth is also associated with asthma, sleep
apnea, and high blood pressure (CDC, Consequences,
2007).
Death. From a longer term perspective, the increase in
cardiovascular disease and diabetes associated with obesity
also has serious consequences in terms of increased mortality. Among adults, approximately 300,000 deaths are
associated with the condition each year (CDC, Consequences, 2007), and these numbers are likely to increase
as today’s children grow older. In fact, some researchers
project that because of the rise in type II diabetes, today’s
population of children may be the first generation in over
a century to experience lower life expectancy than their
parents (Fontaine, Redden, Wang, Westfall & Allison,
2003).
Economic costs. In addition to illness and early death, the
burden of obesity is often conveyed in financial terms.
For example, in the general population obesity-related
health care costs are estimated to have totaled over $117
billion in 2000 (U.S. Department of Health & Human
Services, 2007). Because obesity is associated with
increased absenteeism from work and school, the condition is associated with lost productivity as well (Nord,
Andrews, & Carlson, 2005).
At the same time, it must be recognized that weight is not
always the ideal predictor of health. For example, some
people who are heavy but physically active may be healthier than others who are slim but sedentary (Romero-Corral et al., 2006). Pressure to lose weight may backfire in
Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
the ongoing epidemic of eating disorders and widespread
unhealthy emotional relationships with food, especially
among girls, and in our cultural obsession with body
image and dieting (Schwartz & Brownell, 2007). These
pressures can actually contribute to increasing obesity and
mental health problems. Effective public health interventions to address obesity must steer a careful path to avoid
worsening these negative outcomes (Bauer et al., 2006).
Causal Factors and Conceptual Models
At its most basic level, obesity is often thought of as an
energy imbalance. People gain weight when they consume
more calories than they expend, suggesting that changes
in caloric intake and physical activity are likely the
primary factors responsible for national trends in obesity. In the case of children and adolescents, this theory
is attractive given that studies showing current levels of
nutrition and physical activity leave much to be desired.
For example, only 23 percent of children and adolescents
meet government guidelines for one hour of physical
activity per day (CDC, 2007), and only about one-fifth
eat the recommended five servings of fruits and vegetables
each day (Krebs-Smith et al., 1996). However, researchers have failed to identify a simple relationship between
energy consumption and weight gain with some evidence
suggesting, for example, that children’s overall energy
intake has not increased enough in the past 30 years to
explain current trends in obesity (Nicklas et al., 2001).
Such findings have forced researchers to broaden their
scope to consider a wide array of biological, psychosocial,
and environmental factors that may be at work.
The resulting picture of childhood obesity causality is
dauntingly complex. At the individual level, genetic and
hormonal factors are responsible for regulating metabolism
and feelings of hunger, and these processes may, in turn,
be modified by behaviors ranging from sleeping patterns
to smoking cessation to even the use of air conditioning (Keith et al., 2006). At the same time, emotional and
cognitive factors help determine how people respond to
their biological makeup. Because eating and physical activity are social behaviors, interpersonal supports and stresses
also play a part in determining how people behave. Broader
social and cultural norms are other key indicators; familylevel factors are particularly important for children given
that much of how they live is dependent on their adult
caretakers. Finally, physical, organizational, economic, and
policy environments are important in dictating the health
resources to which people have access, whether in the form
of health information, healthy foods and high-quality
grocery stores, facilities that promote physical activity, safe
neighborhoods, or simply the free time and money needed
to engage in healthy behaviors. To make sense of these
many causal influences, public health researchers and practi­
tioners often use the social ecological framework, which is
a model for thinking about causal factors by their level of
influence (Figure 2).
Figure 2.
CDC, Overweight and Obesity: Social Ecological Model (2006)
Winter 2007
The Role of Public Health Research
Although researchers have convincingly established the
high prevalence and significance of childhood obesity,
they have achieved much less success in intervening to
stop or even slow its rate of increase. For this reason, a
great deal of research is still needed to understand the
mechanisms of childhood obesity and its prevention. The
Institute of Medicine (IOM) recommended continued
research along three lines: (1) behavioral research aimed
at understanding the most important and changeable
factors in obesity etiology; (2) evaluation of prevention
efforts, especially in regard to policy; and (3) communitybased research that explores the role of physical and social
environments (2005, p. 17). In other words, researchers
must refine their general ecological model to determine
causal pathways of greatest importance.
To support these efforts, this report examines major
threads in population approaches to childhood obesity
prevention research to date. Areas examined include
measurement, the school environment, the built environment, policy, and ethnicity and culture. The following discussion explores each area to identify researchinformed recommendations for obesity prevention,
provide an overview of the issue, and spotlight the work
of leading researchers.
III. Measurement
Recommendation
• Develop and use intermediate measures to better
assess the success of obesity prevention efforts.
A fundamental challenge for researchers and practitioners
in obesity prevention is how to measure the effectiveness of prevention programs. Body mass index (BMI),
calculated as weight in kilograms divided by the square of
height in meters, is generally considered to be the “gold
standard” of obesity assessment in adults. Because children are still growing, however, their BMI scores are not
meaningful alone, but instead, are typically considered
by age and sex using CDC growth charts (CDC, 2000
CDC Growth Charts, 2007). Children who fall above the
95th percentile for BMI are considered “obese” while
those between the 85th and 95th percentile are termed
“overweight.” For evaluation purposes, researchers may
consider change in BMI scores or change in BMI categories over time.
Although BMI scores provide a quick and low-cost
method for assessing childhood obesity, the measure is
not without challenges. First, BMI scores do not directly
measure fatness, and so may incorrectly assess children
and adolescents who are heavy because of muscle mass
(CDC, About BMI for children and teens, 2007). Second,
BMI cutoff points are somewhat arbitrary in terms of
health consequences, especially given that the effects of
obesity on health seem to vary by ethnicity. For example,
studies show that, compared to other groups, Asian
Americans’ risk for diabetes increases at a lower BMI
score; thus, more than one system of categorization may
be needed (Razak et al., 2007). Third, adiposity rebound,
which occurs when young children naturally lose weight
for a brief period of time before continued weight gain,
can complicate the tracking of BMI (Eisenmann et al.,
2007). Finally, and perhaps most importantly, BMI measures are very difficult to change, especially in the short
term, because they are the result of many causal factors.
As a result, the effectiveness of short-term interventions,
or those that isolate a small number of factors, is difficult
to assess using BMI. Other measures of body composition, including skin-fold measurements, share many of
BMI’s shortcomings.
For these reasons, researchers and evaluators often use
intermediate measures that assess individuals and/or physical environment instead of, or in addition to, BMI. Tools
of interest include psychosocial surveys, nutrition and
Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
physical activity assessments, and geographic information system (GIS) mapping (Table 2). Like BMI, each of
these measures has strengths and weaknesses, and must be
interpreted within the context of the intervention setting
and population. Further, as intermediate measures, these
may or may not reflect an intervention’s actual impact
on health and obesity. In terms of next steps, experts
agree that existing measures should be improved and new
measures developed to more accurately assess intermediate outcomes.
Table 2: Examples of Intermediate Measures for Obesity Prevention Research and Evaluation
Measure
Description
Strengths
Weaknesses
Psychosocial
surveys
Surveys that measure changes
in knowledge, attitudes, beliefs,
norms, etc.
• Psychosocial measures may be
able to gauge the results of even
short-term interventions.
• Some validated measures
already exist.
• Written surveys may be difficult
for young children to comprehend.
• Psychosocial measures may not
correspond to actual behavior
change.
• Validity may vary across
cultures or age groups.
Nutrition or
activity recall
surveys
Surveys that ask respondents to
name foods consumed or activity
performed within certain time
periods (usually 1-3 days)
• Recalls are relatively quick and
inexpensive to administer.
• Results of popular surveys, such
as the Youth Risk Behavior
Survey, may be compared to
national samples.
• Children often have difficulty
remembering what they ate.
• Important details, such as
portion size and duration of
activity, are difficult to estimate.
Food or activity
diaries
Self-reported accounts of food
intake or physical activity
• Ongoing reporting may be
more complete than recalls.
• Diaries are more participatory
and may provide opportunities
for teaching, goal setting.
• Children may be less likely to
report unhealthy foods.
• Maintaining diaries across settings (e.g., school, after-school,
home) is challenging.
• Literacy and estimation issues
apply.
Food availability
assessments
Inventories of food environments
(e.g., cafeterias or home pantries)
• Inventories give information
about the structural aspects
affecting children’s behaviors.
• They may suggest promising
areas for policy change.
• Gaining access (e.g., children’s
homes) may be difficult, invasive, expensive.
• Ecological fallacy of inferring
individual risk from area factors
must be avoided.
Accelerometer,
pedometer
monitoring
Mechanical techniques for
measuring motion
• Relatively easy to use.
• Quality instruments are expen• Pedometers are easy for children
sive and easily lost.
to understand and can be used • Instruments vary widely in
for teaching, goal setting.
terms of validity and reliability.
• Data can be difficult to interpret.
GIS mapping
Computer-generated maps that
can show the availability of
resources, demographics, etc.
• GIS can assess the structural
aspects of obesity-related
behaviors at the neighborhood
(or larger) level.
• Visual outputs can be compelling.
Winter 2007
• High-quality data may not be
available.
• Requires specialized software
and skills. Resource availability
may not indicate level of use.
SPOTLIGHT
Leslie Lytle, PhD
Leslie Lytle, a professor at the
University of Minnesota, has
helped design and conduct a
number of large-scale research
projects related to health promotion and obesity prevention for
youth, including the TEENS
(Teens Eating for Energy and
Nutrition at Schools) and TAAG
(Trial for Activity for Adolescent
Girls) studies which focused on
adolescent girls. TEENS, completed in 2000, was an intervention study conducted
in 16 middle schools. After the first year of a two-year
program of classroom curricula, schoolwide events, and
family activities, TEENS succeeded in increasing fruit
and vegetable intake and decreasing fat intake in students
(Birnbaum et al., 2002). By the end of the second year of
intervention, though, those student-level effects were no
longer seen (Lytle et al., 2004). School-level effects were
still evident, however, with more healthful choices on the
a la carte lines available for and purchased by students
(Lytle et al., 2006). By contrast, TAAG, a randomized
controlled trial of 36 middle schools, focused on increasing physical activity in middle school-age girls; results of
this study are forthcoming. Both studies are ecological in
nature, seeking to impact not only individual knowledge
and attitudes but also food environments in the home
and school (Elder et al., 2006).
Along with her colleagues, Lytle has developed and
employed a wide array of measures in her work. TEENS
assessment tools, for example, included students’ 24-hour
dietary recall, parent surveys assessing food availability in
the home, and school surveys tracking changes in food
served at school (Lytle et al., 2004). Other measures
used by Lytle include accelerometer data and three-day
physical activity recalls, body composition assessments, as
well as home food inventories, media inventories, school
policy tracking, and even GIS analysis of food and activity availability at the neighborhood level. By expanding
her focus beyond BMI, Lytle’s work has demonstrated
researchers’ success in some of the intermediary steps in
obesity prevention and has shown that environmental factors can be positively impacted.
In discussing next steps for obesity prevention research,
Lytle emphasizes the need to identify the most “potent
and mutable” factors. In her opinion, scientists need
to take a step back from large, multi-center trials to do
smaller scale research in which researchers can play a
more active role in ensuring the fidelity of their interventions. Although the result may have limited external
validity, Lytle feels researchers need to better understand
the most important factors in preventing obesity, and
focus on smaller efficacy trials testing innovative intervention approaches. “When you work on a multi-center
project, you must create an intervention that will work
across a wide range of communities. Often, the most
creative and innovative approaches need to be abandoned
because they may not be feasible to test in all communities or research sites. We’ve seen some successes with the
one-size-fits-all approach, but not the kind of successes
we want.”
At the same time, Lytle believes school- and community-based researchers should re-examine their criteria
for scientific rigor and acknowledge that their goals, like
their methods, often differ markedly from those of clinical researchers. For example, while clinical research may
seek to show a dramatic decrease in BMI across a small
group of individuals using high-tech measurement tools,
community-based research recognizes that small decreases
in BMI across a very large population may have more
dramatic results in terms of health outcomes. Community-based measures may focus on changes in the social
and physical environment rather than on individual body
composition, and they must be appropriate for nonmedical settings. Lytle comments, “Based on published
research, we don’t have an answer to how to prevent
childhood obesity. Every review comes up with the same
conclusion that we can’t say what the best practice is,
but we can’t have people wait. We do know that the very
proximal factors, such as motivation and education, aren’t
enough. We need to focus on the physical environment,
access and availability issues, and neighborhood effects.
Where are the broader leverage points? As a field, this is
what we’re trying to figure out.”
Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
IV. The School Environment
Recommendations:
• Engage students in at least 30 minutes of moderate
to vigorous physical activity each day.
• Encourage the consumption of healthy foods by
increasing the number of healthy options, pricing
those options competitively, and reducing the number of unhealthy foods offered.
• Provide high-quality health education in areas such
as nutrition and physical fitness.
School-based research is prominent in childhood obesity
prevention efforts in part because schools offer access to
children in an educational setting that, at least in theory,
can be modified more easily than home and community
environments. School-based interventions typically aim
to help students make healthier choices by providing
them with health information while at the same time
improving the environment in which their choices are
made. Particular areas of interest include increasing the
amount of physical activity students get each day, improving the nutritional quality of food served at school, and
integrating health education messages into existing school
curricula. Initiatives in these areas require broad-based
support, and education and outreach efforts ideally
extend not only to students but to parents, teachers, and
administrators as well.
Physical Activity
Observers of the school environment have noted that
students move very little during the school day and the
reasons for their inactivity are many. One survey of 157
physical education specialists trained in the Coordinated
Approach to Child Health (CATCH) program suggests
budgetary restrictions in many districts have discouraged
investment in the curricula, staff, and equipment needed
for high-quality physical activity programming (Barroso
et al., 2005). At the same time, respondents reported that
increasing demands for student performance in standardized testing leaves little time for nonacademic pursuits
such as physical fitness (Barroso et al., 2005). Furthermore, opportunities for physical activity that do exist
often emphasize traditional, competitive games, such as
baseball, which do not result in sustained cardiovascular
activity or which may be unappealing to less athletically
inclined students (Rees et al., 2006). Whether because of
these factors or others, studies show that students’ participation in physical activity at school tends to decline with
age and over time; Youth Risk Behavior Survey (YRBS)
data, for example, indicate that high school student
Winter 2007
enrollment in daily physical activity classes dropped from
42 percent in 1991 to 25 percent in 1999 (CDC, 2006).
Despite financial and other barriers faced by school communities, many authorities in childhood obesity prevention, including the Institute of Medicine (IOM), agree
that children and adolescents must get more exercise at
school, where they spend so many of their waking hours.
Thirty minutes of moderate to vigorous physical activity
(MVPA) per day is a common goal (IOM, 2005, p. 259).
Strategies for achieving greater frequency and intensity of
activity include:
• Introducing new physical activity curricula that
emphasize cooperative games and continuous movement. The Sports, Play, and Active Recreation for Kids
(SPARK) program is one example (Sallis et al., 1997);
• Offering attractive alternatives to traditional sports,
such as dance, helps engage older students, especially
girls, who are least likely to be active (IOM, 2005);
• Integrating physical activities throughout the school
day (IOM, 2005); and
• Augmenting after-school and extracurricular programs
for students as well as activity-related events or classes
for families and staff (IOM, 2005).
In addition to increasing physical activity opportunities, researchers have sought ways to objectively evaluate
the quality of activity provided by these programs. Tools
such as SOFIT (System for Observing Fitness Instruction
Time) have been developed to assess an activity session’s
duration and intensity (McKenzie, Sallis & Nader, 1991).
Nutrition
A second major area of interest in school-based obesity
prevention is nutrition. The school environment, like
that of society at large, often discourages healthy choices
by providing students with too many attractively packaged, inexpensive, and unhealthy food options. This
balance is difficult to change. Candy, soda, snack chips,
and other energy-dense foods are often readily available to
students through “a la carte” cafeteria programs, vending machines, and fundraisers. As “competitive foods,”
these offerings are not subject to the USDA’s regulations,
which provide guidelines for the nutritional quality of
food served as part of the National School Lunch Program (Greves & Rivara, 2006). Adding to the problem is
the fact that resource-poor schools may be unwilling to
give up the revenue the sales of competitive foods generate, whether in the form of actual profits or in terms of
contracts with soda and snack food manufacturers, some
of whom provide schools with support for extracurricular
activities such as sports teams in exchange for advertising
and sales opportunities. School staff, especially food service employees, are often concerned that if healthy foods
are offered, participation in school lunch programs will
decrease as will the ability to recoup costs. A national survey of school nutrition services representatives found that
these perceptions are hard to change, despite the anecdotal evidence from the field suggesting that competitive
pricing programs promoting the sale of healthy foods
have failed to result in negative financial consequences
(Greves & Rivara, 2006).
Even in well-funded schools, however, unhealthy foods
are common; they are often used in the context of classroom parties or as rewards for good behavior, a practice
that may underscore the value of these foods for students.
Furthermore, federally funded school lunch programs,
though highly regulated in terms of nutritional content,
are not always as healthy or appetizing as they might be.
With many schools employing the services of outside
contractors for food service, students’ meals may travel
hundreds of miles before reaching them, and strict rules
concerning meal composition limit the use of some
healthful ingredients such as soy-based proteins (Bauer
et al., 2006). Factors such as these serve to undermine
the good intentions of even the most nutrition-conscious
students.
Public health practitioners have sought to address the
food environment of schools by increasing healthy
options, making options more attractive, and engaging
students in the process of food preparation and production. In these ways, program planners hope to create
what is sometimes referred to as a “person-environment
fit,” in which students have the environmental supports
they need to make healthy choices. In addition to simply
substituting healthy offerings for unhealthy ones, efforts
to improve the food environment and introduce students
to new food include:
• Adoption of classroom tasting and cooking curricula,
such as California State Department of Health Service’s Harvest of the Month (2005);
• School cafeteria initiatives, such as the Johns Hopkins
Center for a Livable Future’s Meatless Monday project, which introduced and promoted low-fat, meatless foods into the menu (Johns Hopkins Bloomberg
School of Public Health, 2005).
• Food and nutrition education programs, such as Food
is Elementary by Dr. Antonia Demas, that teach
school gardening, nutrition education, and cooking
skills (Food Studies Institute, 2006); and
• Competitive pricing programs aimed at making
healthy foods a better value and more attractive to
students in terms of cost and variety. The CHIPS
(Changing Individuals’ Purchase of Snacks) program
as implemented in Minnesota middle schools is one
example (French, 2003).
Through programs such as these, public health practitioners attempt to redefine students’ relationships with food
by changing both individual attitudes and social norms
to support the consumption of healthy foods, especially
fruits and vegetables, while discouraging opportunities for
students to take in empty calories.
Health Education in Schools
A third area of focus in school-based research is health
education related to nutrition and physical activity. Studies such as CATCH have shown that classroom teachers
often have difficulty using traditional health education
curricula for several reasons. First, because health-related
knowledge is not part of required scholastic assessments,
it is often covered superficially and without the curricular support devoted to other subjects (Hoelscher et al.,
2004). In order to provide health education in an ongoing fashion, teachers often note the need to tie health
information to existing curricula, and math and science
classes have proven to be a particularly good fit in this
regard (Hoelscher et al., 2004). Additionally, some teachers feel they lack the knowledge necessary to teach health
topics. Many obesity prevention interventions, therefore,
acknowledge the need to extend health education activities to include teachers and parents. The Eat Well and
Keep Moving program is one example of an integrated
approach that incorporates teachers and families in health
education efforts (Gortmaker et al., 1999).
10 Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
SPOTLIGHT
Benjamin Caballero, MD, PhD
Benjamin Caballero, a professor in international health
and human nutrition at the
Johns Hopkins Bloomberg
School of Public Health,
has been at the forefront of
childhood obesity prevention
through research including
the Pathways study. Based
in 41 elementary schools,
Pathways was a randomized controlled trial of over
1,700 American Indian third-, fourth-, and fifth-graders
(Caballero et al., 2003). Pathways was designed to be a
culturally sensitive, ecological approach to school-based
obesity prevention (Davis et al., 1999), and involved
four primary components: 1) classroom curricula related
to physical fitness and nutrition; 2) a physical activity
curriculum known as SPARK (Sports, Play, and Active
Recreation for Kids); 3) collaboration with food service
staff to lower the fat content of school food; and 4) family
events and resources. Though the study did not result
in changes in children’s body composition, Pathways
researchers did show improvements in students’ dietary
fat intake and health knowledge.
Caballero also emphasizes the need to take an integrated
approach to understanding obesity: “We’ve tended to
approach obesity prevention in the same way as obesity
treatment—restricting people’s diets, for example—and
in the real world this doesn’t work. There’s no single
approach for making a dent in the problem.” Comparing
obesity prevention to campaigns in the 1980s and 90s
to reduce tobacco use, Caballero believes that researchers need to work to understand obesity in the context of
parenting, family life, school settings, and the broader
community and policy environments. While the school
setting is important, he wants researchers to understand
that schools are only part of the solution and that, furthermore, teachers and administrators in these settings are
often facing a wide array of serious and more immediate
problems, from school violence to performance mandates
to staff turnover, which may limit their involvement in
obesity prevention efforts. Caballero believes that by
bringing in more stakeholders, including community
leaders, politicians, and industry leaders, public health
researchers may be able to develop more effective and
sustainable interventions.
In discussing school-based work in obesity prevention,
Caballero emphasizes that high-quality interventions
do not necessarily result in decreased BMI, even when
students’ energy intake decreases and physical activity
increases; his literature review of 15 school-based interventions showed only one was successful in terms of lowering BMI. In Caballero’s opinion, many confounding
factors—such as increased eating outside the school setting—may mask healthy changes happening in schools.
For this reason, he stresses the importance of developing
intermediary measures for studying obesity. He explains,
“We need to consider additional kinds of measures.
Attitudes and other psychosocial factors are important.
We should also learn from researchers with experience in
environmental exposures to better understand the physical environment’s impact on obesity.”
Winter 2007
11
V. The Built Environment and Neighborhood Factors
Recommendations
• Make communities more walk-able and bike-able.
• Increase access to healthy foods.
Studies of the built environment in the context of childhood obesity prevention emphasize the effect that city or
community planning efforts, or lack thereof, may have
on children’s health behaviors. As the name implies, the
built environment includes structures such as sidewalks,
playgrounds, and markets that impact opportunities for
health, but also extends to more abstract ideas about
neighborhood design and governance that impact community dynamics, safety, and other social interactions.
The built environment has been of particular interest to
those involved in health disparities research because it
is directly associated with many barriers to health, such
as limited availability of and access to fresh produce and
other healthy foods, and the exposure to crime often
experienced by people living in resource-poor communities. Urban factors such as crowding are often the first to
come to mind in regard to the built environment, but
suburban and rural communities also experience structural barriers to health, such as a lack of sidewalks and
limited street connectivity.
In terms of physical activity, researchers focusing on the
built environment note that many factors associated with
urban and suburban development limit children’s opportunity for unstructured recreation outside the home.
Concerns about crime are a leading reason that parents
keep their children indoors, but traffic and a lack of wellmaintained playgrounds and greenways are also important (Salmon & Timperio, 2007; Gordon-Larsen et al.,
2000). Researchers in public health study the effects such
factors have on health behaviors, and, in particular, the
use of GIS analysis has emerged as a powerful assessment
tool (Sallis & Glanz, 2006). At the same time, others have
sought to improve the built environment, particularly
with the intention of establishing communities that are
well-suited for walking, biking and recreational activities. Such efforts include community planning activities
designed to improve sidewalks and bike paths as well as
community organization efforts to provide supervision
and social support for active transportation. The National
Highway Traffic Safety Administration’s Safe Routes to
School is one example of a program aimed at helping
families negotiate the challenges of the built environment
(Staunton et al., 2003).
Diet, like physical activity, is also determined in part by
the built environment; families who have easy access to
affordable, high-quality fruits and vegetables are more
likely to consume them (Sallis & Glanz, 2006). Researchers have noted with concern that low-income communities offer below-average access to supermarkets and fresh
produce, but greater access to liquor stores, as compared
to wealthier neighborhoods (Moore & Diez Roux, 2006).
Public health practitioners have attempted to improve
availability of and access to healthy foods in low-income
communities by establishing farmers markets, instituting
mobile vending routes, and partnering with local merchants for “corner store enhancement” to provide a greater
selection of competitively priced fruits and vegetables
(Bolen & Hecht, 2003, p. 18). The Baltimore Healthy
Stores Project, implemented by Dr. Joel Gittelsohn,
conducted by the Bloomberg School’s Center for Human
Nutrition, is one intervention that targets the built environment in low-income communities by improving the
nutritional quality of food offered in local grocery and
convenience stores, providing special labels to identify
healthy choices, and creating health education materials
to raise public awareness of these efforts. Policy efforts to
increase affordability of healthy food through food aid
programs such as Women, Infants and Children (WIC)
and food stamps are another example (Quaid, 2006).
12 Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
SPOTLIGHT
Penny Gordon-Larsen, PhD
Penny Gordon-Larsen is an
assistant professor of nutrition
at the University of North
Carolina School of Public
Health, where her research
focuses on the socio-demographic and environmental
determinants of obesity.
Gordon-Larsen is one of
only a few researchers to focus specifically on the relationship between obesity and the built environment,
an interest that was sparked by her dissertation work in
West Philadelphia, Pennsylvania. “In my [communitybased participatory research] work, I talked to kids to
try to understand the challenges they faced living in an
urban environment. What about the urban environment
predisposed inner city kids to obesity? One issue that just
kept coming up was that despite understanding the need
for healthy diet and activity, the kids couldn’t actually get
fruits and vegetables. They lived in an environment with
easy access to high-fat, energy-dense foods, and without
safe access to recreational facilities.” Through the University of Pennsylvania Center for Community Partnerships’
Urban Nutrition Initiative (2007), Gordon-Larsen and
her colleagues were able to use research to guide public
health practice. Specifically, the center has worked to
increase the availability of food by instituting after-school
fruit and vegetable stands, school-based gardens, and family fitness centers along with nutrition education.
Discussing her current work, Gordon-Larsen feels
research on the built environment is becoming both
more common and more sophisticated, thanks in part
to the growing popularity of GIS analysis. At this point
researchers have firmly established the importance of this
area of study: “We have good evidence that poor communities are at a disadvantage in terms of healthy foods and
physical activity, whether directly in terms of availability
or indirectly in terms of concerns about crime.” GordonLarsen emphasizes, however, that research related to the
built environment is still in its infancy and has introduced many new challenges. “It’s very hard to implement
and collect intervention data aimed at changing the built
Winter 2007
environment because we don’t live in an experimental
world,” she says. For this reason researchers must be on
the lookout for “natural experiments” in which policy and
environment changes give researchers opportunities for
making before-and-after comparisons.
In terms of advancing future studies, Gordon-Larsen
believes researchers need to pursue more rigorous longitudinal study designs. She is in the process of finishing a longitudinal database that will help her describe
the effects of environmental change on behaviors. Her
primary targets are modifiable factors, such as individuals’
distance from and access to fitness facilities, which can be
used to inform policy, as well as more general characterization of the physical environment. “The urban-ruralsuburban gradations commonly used in research are so
big. So we’re trying to characterize these areas in more
detail so that we can understand what it really means to
live in suburbia, for example.”
Gordon-Larsen advises researchers with an interest in
the built environment to partner with their counterparts in geography and urban planning to facilitate the
negotiation of data. She explains, “Researchers need to
understand the intricacy of working with large databases
[such as a national GIS database]. If you’re not careful
with quality, you won’t get the data you need to support
the research.” Gordon-Larsen hopes that as work related
to the built environment gains recognition in the area of
obesity, researchers with other behavioral interests such as
alcohol and tobacco use will join her efforts.
13
VI. Marketing, Industry, and Public Policy
Recommendations
• Advocate for regulation of youth marketing.
• Strengthen consumers’ ability to make informed
food choices, gain access to accurate information,
and take an active role in influencing food policy. In addition to individual and environmental factors, economic and political considerations must feature prominently in any discussion of the public health response
to childhood obesity. More specifically, how can public
health messages compete with for-profit corporations
that have billions of dollars to spend marketing energydense foods and sedentary entertainment to children and
youth? What constitutes predatory advertising, and how
can youth advocates work to regulate potentially harmful
media influences? What can be done at the policy level to
create incentives for the production of health-promoting
foods and products? Questions such as these that consider
the political and economic aspects of obesity are essential
for understanding key macro-level targets of intervention,
which include the areas of youth marketing and national
food policy, among others.
Youth Marketing
The marketing of unhealthy foods to youth has been
widely discussed in the public health community as a
contributing factor to the obesity epidemic, and poses
a particular concern given the pervasiveness of advertising media and the vulnerability of children and youth to
advertising messages (IOM, 2000). The majority of youth
marketing occurs through television with studies showing
that the average child watches as many as 400,000 television ads each year; movies, the Internet, print materials,
and advertising in schools also contribute to exposure
(Committee on Communications, American Academy of
Pediatrics, 2006). Studies have consistently shown that
even in very young children television viewing is positively correlated with consumption of advertised foods,
which are often of low nutritional value (Wiecha et al.,
2006). Ironically, at the same time television ads promote
unhealthy consumption, they may also foster poor body
image in viewers by idealizing thin or even underweight
body types that children and adolescents may find impossible to attain through healthy means. Through content
analysis of available media as well as survey studies,
researchers work to characterize the media environment
and to determine its effects on children and adolescents.
The public health community has attempted to counter
the effects of detrimental marketing by creating competing messages that promote health, by educating youth to
be more media savvy, and by using media to build support for prevention-related policy initiatives. The CDC’s
VERB Campaign, for example, is a well-known communication intervention that used a variety of media to
impart the message that being physically active is socially
desirable (Huhman et al., 2005). Similarly, curricula
such as the National Institute of Child Health & Human
Development’s Media Smart Youth: Eat, Think, and Be
Active! are designed to help children and adolescents
become more critical consumers of marketing messages
(2005). Finally, media have been an avenue for public discourse about the national diet in recent years with social
critics attracting widespread attention for such work
as Schlosser’s Fast Food Nation (2001). In these ways,
counter-narratives have been constructed to compete with
the commercial marketing messages that encourage the
consumption of unhealthy foods.
If the aforementioned strategies take an oppositional
stance to marketing and corporate interests, an alternative tactic that has gained ground in recent years is
more cooperative in nature; in several notable instances,
industry leaders have been persuaded to adopt self-regulatory measures. For example, in an agreement brokered by
former President Bill Clinton, Arkansas Governor Mike
Huckabee, and the American Heart Association, major
manufacturers of soft drinks have agreed to replace the
sale of beverages with added sugars in schools with water
and fruit juices (Burros & Warner, 2006). Through the
application of public pressure for corporate responsibility, businesses may be encouraged to operate in ways
more conducive to children’s health, and the Institute of
Medicine and others have recommended that efforts in
this area continue (IOM, 2006).
At the same time, critics of these efforts argue that industry self-regulation is not always strong or well-enforced
enough to result in significant change. Given the urgency
of the obesity crisis, they believe that external regulation
by the federal government is also merited (Kelly, 2005).
However, despite increased attention to the issue, including a recent forum held by the Federal Trade Commission
(2006) at the urging of the IOM, proponents of federal
regulation have made little headway to date against strong
political opposition.
14 Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
Federal Food Policy
Concerns about childhood obesity have led to greater
attention to the role of the federal government in other
areas as well, and the USDA’s National School Lunch
Program (NSLP) and the Farm Bill are two examples.
The NSLP, which provides meals to approximately 30
million students each school day, currently issues nutritional guidelines that specify certain nutritional standards
for the food, including limits on the number of allowable
calories from fat. However, critics of the NSLP, including
the Institute of Medicine, argue that these guidelines are
outdated and note, for example, that the NSLP currently
makes no requirements for serving fruits and vegetables
(2005). Particularly because the NSLP serves as a daily
source of food for many low-income youth who are
at increased risk for obesity, policy initiatives aimed at
improving and enforcing nutritional standards for the
NSLP may prove to be an effective strategy for obesity
prevention (Weiss & Smith, 2004).
The importance of the national Farm Bill is another area
of federal policy that is emerging as important to the
public health response to obesity. This agricultural policy
encourages the production of certain commodities, such
as corn and soy, over other crops including fruits and
vegetables (see Spotlight: David Wallinga). If the priorities of the Farm Bill were shifted to favor the production
of healthier foods, advocates believe that policymakers
could significantly impact the national food environment
(Schoonover & Muller, 2006). Furthermore, because
the Farm Bill plays a role in dictating the foods offered
through the NSLP, it presents an especially attractive target for intervention. Public health professionals work to
build public support for policy reform in these and other
areas to help ensure that consumers have greater access
to healthy foods and nutritional information about those
foods.
Winter 2007
SPOTLIGHT
David Wallinga, MD
David Wallinga, director of
the Food and Health Program
at the Institute for Agriculture
and Trade Policy (IATP) in
Minneapolis, advocates and
conducts research concerning how food production and
packaging impacts public
health, and especially the
health of children. IATP
programs focus, for example,
on industrial contaminants
deposited in the food chain, and on farm practices resulting in chemical residues and antibiotic resistance. IATP
also advocates for more sustainable food systems that
provide not only healthier food but also better social,
environmental, and economic health for communities.
Wallinga stresses that chemical additives are not the
only way current agricultural practices are problematic;
America’s lopsided emphasis on the production of soy and
corn has contributed to the proliferation and ready accessibility of high-calorie, low-nutrient foods that encourage
obesity. Sustained by Farm Bill policies, these “commodity” crops are overproduced, driving down their price. As
a result, processed foods using corn and soy derivatives
such as high-fructose corn syrup and hydrogenated cooking oils, can be produced cheaply and with high profit
margins, often edging out healthier foods in the national
diet. Indeed, Wallinga notes that obesity rates have risen
in step with the rising production and consumption of
high-fructose corn syrup, which are made possible by the
Farm Bill because of financial support for these crops.
Given that the production of artificially inexpensive commodity grains largely benefits food processors and largescale meat producers rather than farmers (Schoonover &
Muller, 2006), Wallinga looks forward to future collaboration between the public health and farming communities. In particular, he hopes that sustained advocacy will
one day transform the Farm Bill, which benefits the business interests of a select few, into what he calls a “Healthy
Food Bill,” which, by encouraging the production of
healthy foods, will sustain both the people who grow food
as well as those who eat it.
15
VII. The Ethnicity Gap and Cultural Contexts
Recommendation
• Engage local governments and community groups,
particularly those most affected by obesity, in community and policy initiative.
Obesity rates have increased in almost all sectors of the
U.S. population, but some groups suffer more than others, including women in certain ethnic and racial minorities. Obesity affects almost half of African American
women, for example, as compared to less than one-third
of white women, and this population difference begins
in childhood (Flegal et al., 2002). Lower socioeconomic
status is also associated with obesity, though this association may be weakening over time (Wang & Zhang,
2006). Many public health researchers are interested in
understanding mechanisms of ethnic and racial disparities in obesity and in addressing those factors to reduce
the ethnicity gap (Gordon-Larsen et al., 2006). Racial
disparities may arise through many pathways, including population differences in access to healthy food, safe
places to exercise, and time to engage in either. Psychobiological factors may also play a role. For example, the
stress hormone cortisol may also affect obesity, and racial
minorities may experience more stress due to social and
economic factors including the effects of living in an
unequal society (Gordon-Larsen et al., 2006).
This appreciation of the role of cultural influences often
goes hand in hand with a desire to engage populations in
a more participatory approach to obesity prevention so
as to translate local knowledge into action. Specifically,
public health advocates have sought to organize local and
community organizations to respond to the problem of
obesity in their own localities. Food security--the ability to access the food needed for health--is one issue that
has gained traction in recent years, as community groups
have employed arguments of social justice to secure more
equitable access to fresh fruits and vegetables and other
healthy foods. The Garden of Eden Project, which organized church-based produce markets in African American
communities in St. Louis, Missouri, is one example of
this approach (Baker et al., 2006). Funding agencies are
increasingly encouraging, and even requiring, their grantees to secure community participation, underscoring the
importance of this approach.
In studying differences in obesity rates across populations, many have pointed to the need to arrive at a more
nuanced understanding of the cultural context for eating
and physical activity. How do different cultures encourage or discourage obesity? How does American consumer
culture impact traditional patterns of diet and physical
activity? What are cultural norms related to body image?
What modifications of traditional recipes will be accepted
as healthier but still appealing alternatives? Researchers of
cultural context argue that these questions are critical not
only to understanding obesity on a theoretical level, but
to designing culturally appropriate interventions as well.
In particular, many believe that additional qualitative
research is needed to provide in-depth analysis of cultural
phenomena.
16 Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
SPOTLIGHT
Shiriki Kumanyika, PhD
Shiriki Kumanyika studies
obesity treatment and prevention with a focus on culture
and ethnicity. A professor of
epidemiology at the University of Pennsylvania School
of Medicine, Kumanyika
was the principal investigator of the recently completed
SHARE (Supporting Healthy
Activity and Eating Right
Everyday) study. SHARE paired African American participants with family members or friends to investigate
the role of interpersonal relationships in weight-related
lifestyle modification (Kumanyika, 2003). Through
cultural tailoring and social support, Kumanyika and her
colleagues were hoping to increase their participants’
ability to make and sustain changes in their eating and
activity practices over a two-year period. Results are
currently being analyzed, including responses to an exit
questionnaire about how specific cultural adaptations
were viewed by the participants.
Kumanyika emphasizes that studies such as SHARE are
critical to understanding the social and cultural contexts
that contribute to the persistent ethnicity gap in obesity
prevalence. In discussing her work, she notes that African
American women are particularly vulnerable to obesity,
citing a number of possible determinants of overeating, including stress, history of material deprivation,
and the prominent role of food in cultural celebrations.
Kumanyika says the problem of obesity related to overeating may be self-perpetuating: “Seeing so many heavy
African Americans makes people think it’s natural, that
they don’t need to be concerned about higher rates of
obesity in this population. In reality, the excess of obesity
is far from benign.”
the African American Collaborative Obesity Research
Network (AACORN, www.aacorn.org) aimed at increasing the quality, quantity, and translation of research in
African American communities. Kumanyika believes
researchers need to take a deeper look into the role that
food plays in people’s lives, whether in terms of stress
relief, social interaction, or parenting, in order to tailor
interventions in a more meaningful way. “I think we
health professionals, who divide up health problems to
study them, need to make sure we put everything back
together as we go back into the population,” she said. “All
of the changes that have happened in society that affect
how people behave are part of an integrated system of
how we live. For example, relationships between parental
employment, stress, and disadvantage flow directly to
how children are parented, including how children are
fed. The factors leading to many [chronic] diseases are
similar, and we could save money and time if we studied them in context.” In terms of qualitative methods,
Kumanyika emphasizes the importance of unstructured
interviews, ethnography, and participant observation. She
has found content analysis especially valuable, and her
work is informed, in part, by feminist literature such as
bell hooks’ Sisters of the Yam (1994), which serves as one
of many examples of how knowledge from the humanities
can be relevant to public health.
In addition to cultural factors, Kumanyika believes the
public health community should continue to examine environmental factors, such as targeted marketing
campaigns and increased availability of unhealthy foods
in communities of color, and how these factors impact
obesity levels. In her view, through a contextualized,
integrated approach, researchers may be more successful
in reaching those who are currently suffering most from
obesity, people of color.
In the future, Kumanyika hopes to see more emphasis
placed on qualitative research and integration of knowledge from a wider range of disciplines to help practitioners develop an understanding of culture beyond mere
food preferences. To facilitate this work, she founded
Winter 2007
17
VIII. Conclusion
Research literature indicates that findings related to childhood obesity prevention are best described as “mixed” and
that researchers remain years away from establishing the
evidence-based best practice models used in other areas
of public health and medicine. Nevertheless, leaders in
the field are largely in agreement on a number of important points. First, individually focused efforts aimed at
awareness and education are necessary but not sufficient
for addressing the complex problem of childhood obesity.
Instead, public health researchers must adopt a multipronged, ecological approach that acknowledges social,
physical, and policy environments critical to achieving
and maintaining health. Second, experts emphasize the
importance of a sustained approach to obesity research
and prevention activities. The sustained approach is
important because diet and nutrition issues are particularly vulnerable to fads and the public and media’s
reaction and interpretation of research. Health behaviors
and, in turn, body composition are the result of years of
daily practice and socialization, bounded by socio-environmental and physiologic constraints. They are, therefore, resistant to any single or short-term intervention.
Instead, sustained and integrated efforts ranging from
local initiatives to national policies are needed to create
environments that better support health behaviors. Given
the magnitude and severity of the problem, few areas of
public health intervention hold as great an opportunity to
contribute to the overall health, longevity, and quality of
life of future generations.
18 Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
References
Baker, E. A., Kelly, C., Barnidge, E., Strayhorn, J.,
Schootman, M., Struthers, J., & Griffith, D. (2006). The
Garden of Eden: Acknowledging the impact of race and
class in efforts to decrease obesity rates. American Journal
of Public Health, 96(7), 1170-114.
Centers for Disease Control and Prevention. (2006).
Overweight and obesity: State-based programs: Social Ecological Model. Retrieved May 20, 2007, from http://www
.cdc.gov/nccdphp/dnpa/obesity/state_programs/se_
model.htm.
Barroso, C. S., McCullum-Gomez, C., Hoelscher, D. M.,
Kelder, S. H., & Murray, N. G. (2005). Self-reported
barriers to quality physical education by physical education specialists in Texas. Journal of School Health, 75(8),
313-19.
Centers for Disease Control and Prevention. (2006).
YRBSS: Youth Risk Behavior Surveillance System. Retrieved
February 15, from http://www.cdc.gov/HealthyYouth/
yrbs/index.htm.
Bauer, K. W, Patel, A., Prokop, L. A., & Austin, S. B.
(2006). Swimming upstream: faculty and staff members
from urban middle schools in low-income communities
describe their experience implementing nutrition and
physical activity initiatives. Preventing Chronic Disease, 3
(2):A37.
Birnbaum, A. S., Lytle, L. A., Story, M., Perry, C. L., &
Murray, D. M. (2002). Are differences in exposure to a
multicomponent school-based intervention associated
with varying dietary outcomes in adolescents? Health
Education and Behavior, 29(4), 427-43.
Bolen, E., & Hecht, K. (2003). Neighborhood groceries:
New access to healthy food in low-income communities.
California Food Policy Advocates. Retrieved February 15,
2007, from http://www.cfpa.net/Grocery.PDF.
Bray, G. A., Nielsen, S. J., & Popkin, B. M. (2004).
Consumption of high-fructose corn syrup in beverages
may play a role in the epidemic of obesity. American
Journal of Clinical Nutrition, 79(4), 537-43.
Burros, M., & Warner, M. (2006, May 4). Bottlers agree to a ban on sweet drinks. New York Times.
Retrieved February 23, 2007, from http://www.nytimes.
com/2006/05/04/health/04soda.html?ex=1304395200&
en=80149e91b4b733bb&ei=5088&partner=rssnyt&em
c=rss#.
Caballero, B., Clay, T., Davis, S. M., Ethelbah, B., Rock,
B. H., Lohman, T., et al. (2003). American Journal of
Clinical Nutrition, 78, 1030-38.
California State Department of Health Service. (2005).
Harvest of the month: Growing healthy students.
Retrieved January 10, 2007, from http://www.harvest
ofthemonth.com.
Winter 2007
Centers for Disease Control and Prevention. (2007).
2000 CDC Growth Charts: United States. Retrieved January 19, 2007, from http://www.cdc.gov/growthcharts/.
Centers for Disease Control and Prevention. (2007). Body
Mass Index: About body mass index for children and teens.
Retrieved June 26, 2007, from http://www.cdc.gov/nccdphp/dnpa/bmi/childrens_BMI/about_childrens_BMI.
htm#using%20an%20adult%20BMI%20calculator.
Centers for Disease Control and Prevention. (2007).
Overweight and obesity: Childhood overweight: Consequences.
Retrieved January 10, 2007, from http://www.cdc.gov/
nccdphp/dnpa/obesity/childhood/consequences.htm.
Centers for Disease Control and Prevention. (2007).
Overweight and obesity: Childhood overweight: Overweight
prevalence. Retrieved January 10, 2007, from http://www
.cdc.gov/nccdphp/dnpa/obesity/childhood/prevalence.
htm.
Centers for Disease Control and Prevention. (2007).
Prevalence of overweight among children and adolescents.
Retrieved September 20, 2007, from http://www.cdc.
gov/nchs/products/pubs/pubd/hestats/overweight/ overwght_child_03.htm#Table%201.
Committee on Communications, American Academy of
Pediatrics. (2006). Children, adolescents, and advertising.
Pediatrics, 118(6), 2563-69.
Davis, S. M., Going, S. B., Helitzer, D. L., Teufel, N.
I., Snyder, P., Gittelsohn, J., et al. (1999). Pathways: A
culturally appropriate obesity-prevention program for
American Indian schoolchildren. American Journal of
Clinical Nutrition, 69(suppl), 796S-802S.
Ebbeling, C. B., Pawlak, D. B., & Ludwig, D. S. (2002).
Childhood obesity: Public-health crisis, common sense
cure. Lancet, 360, 473-82.
19
Eisenberg, M. E., Neumark-Sztainer, D., & Story, M.
(2003). Associations of weight-based teasing and emotional well-being among adolescents. Archives of Pediatric
and Adolescent Medicine, 157, 733-38.
Eisenmann, J. C., Heelan, K. A., & Welk, G. J. (2004).
Assessing body composition among 3- to 8-year-old children: Anthropometry, BIA, and DXA. Obesity Research,
12(10), 1633-40.
Elder, J. P., Lytle, L., Sallis, J. F., Young, D. R., Steckler,
A., Simons-Morton, D., et al. (2006). A description of
the social-ecological framework used in the trial of activity for adolescent girls (TAAG). Health Education Research
Advance Access. Retrieved January 14, 2007, from http://
her.oxfordjournals.org/cgi/content/abstract/cyl059v1.
Fagot-Campagna, A., Pettitt, D.J., Engelgau, M.M.,
Burrows, N. R., Geiss, L.S., Valdez, R., et al. (2000).
Type 2 diabetes among North American children and
adolescents: An epidemiologic review and a public health
perspective. Journal of Pediatrics, 136(5) , 664-72.
Federal Trade Commission. (2006). Perspectives on marketing, self-regulation, & childhood obesity. Retrieved June
26, 2007, from http://www.ftc.gov/os/2006/05 Perspect
ivesOnMarketingselfRegulation&Childhood ObesityFT
CandHHSReportonJointWorkshop.pdf.
Flegal, K.M., Carroll, M.D., Ogden, C.L., Johnson,
C.L. (2002). Prevalence and trends in obesity among US
adults, 1999-2000. JAMA, 288(14), 1723-27.
Food Studies Institute. (2006). Food is Elementary.
Retrieved June 25, 2007, from http://www.foodstudies
.org/Curriculum/index.htm.
Fontaine, K. R., Redden, D. T., Wang, C., Westfall, A.
O., Allison, D. B. (2003). Years of life lost due to obesity.
Journal of the American Medical Association, 289(2),
187-93.
French, S.A. (2003). Pricing effects on food choices.
Journal of Nutrition, 133(3), 841S-43S.
Gordon-Larsen, P., Adair, L. S., Nelson, M. C., &
Popkin, B. M. (2004). Five-year obesity incidence in the
transition period between adolescence and adulthood:
The National Longitudinal Study of Adolescent Health.
American Journal of Clinical Nutrition, 80(3), 569-75.
Gordon-Larsen, P., McMurray, R. G., & Popkin, B. M.
(2000). Determinants of adolescent physical activity and
inactivity patterns. Pediatrics, 105(6), E83.
Gortmaker, S. L., Cheung, L. W., Peterson, K. E., Chomitz, G., Cradle, J. H., Dart, H., et al. (1999). Impact of
a school-based interdisciplinary intervention on diet and
physical activity among urban primary school children:
Eat well and keep moving. Archives of Pediatric and Adolescent Medicine, 153(9), 975-83.
Greves, H. M., & Rivara, F. P. (2006). Report card on
school snack food policies among the United States’
largest school districts in 2004-2005: Room for improvement. International Journal of Behavior, Nutrition, and
Physical Activity, 3, 1.
Hoelscher, D. M., Feldman, H. A., Johnson, C. C.,
Lytle, L. A., Osganian, S. K., Parcel, G. S., et al. (2004).
School-based health education programs can be maintained over time: Results from the CATCH institutionalization study. Preventive Medicine, 38(5), 594-606.
hooks, b. (1994). Sisters of the yam: Black women and
self-recovery. Cambridge, MA: South End Press.
Huang, T. T., & Horlick, M. N. (2007). Trends in childhood obesity research: A brief analysis of NIH-supported
efforts. Journal of Law, Medicine, & Ethics, 35(1) 148-53.
Huhman, M., Potter, L. D., Wong, F. L., Banspach, S.
W., Duke, J. C., & Heitzler, C. D. (2005). Effects of a
mass media campaign to increase physical activity among
children: Year-1 results of the VERB campaign. Pediatrics,
116(2), e277-84.
Institute of Medicine. (2005). Preventing childhood
obesity: Health in the balance. Washington, DC: National
Academies Press.
Institute of Medicine. (2006). Food marketing to children and youth: Threat or opportunity? Washington, DC:
National Academies Press.
Johns Hopkins Bloomberg School of Public Health.
(2002). Public health schools offer their support to
“Meatless Monday” Health Campaign. Retrieved June
25, 2007, from http://www.jhsph.edu/publichealthnews/
press_releases/PR_2002/meatless_deans.html.
Keith, S. W., Redden, D. T., Katzmarzyk, P. T., Boggiano,
M. M., Hanlon, E. C., Benca, R. M., et al. (2006). Putative contributors to the secular increase in obesity: exploring the roads less traveled. International Journal of Obesity,
30(11), 1585-94.
Kelly B. (2005). To quell obesity, who should regulate
food marketing to children? Global Health, 1, 9.
20 Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
Kimm, S. Y., & Obarzanek, E. (2002). Childhood obesity: A new pandemic of the new millennium. Pediatrics,
110(5), 1003-1007.
Krebs-Smith, S. M., Cook, A., Subar, A. F., Cleveland,
L., Friday, J., & Kahle, L. L. (1996). Fruit and vegetable
intakes of children and adolescents in the United States.
Archives of Pediatric & Adolescent Medicine, 150(1), 81-86.
Kumanyika, S. (2003). SHARE overview. Retrieved January 10, 2007, from http://www.cceb.upenn.edu/pages/
share/overview.html.
Kumanyika, S., Jeffery, R. W., Morabia, A., Ritenbaugh,
C., & Antipatis, V. J. (2002). Public Health Approaches
to the Prevention of Obesity (PHAPO) Working Group
of the International Obesity Task Force (IOTF). Obesity
prevention: The case for action. International Journal of
Obesity and Related Metabolic Disorders, 26(3), 425-36.
Lytle, L., Kubik. M., Perry, C., et al. (2006). Influencing
healthful food choices in school and home environments:
Results from the TEENS study. Preventive Medicine, 43,
8-13.
Lytle, L. A., Murray, D. M., Perry C. L., Storey, M., Birmbaum, A. S., Kubik, M. Y., et al. (2004). School-based
approaches to affect adolescents’ diets: Results from the
TEENS study. Health Education & Behavior, 31, 270-87.
McKenzie, T. L., Sallis, J. F., & Nader, P. R. (1991).
SOFIT: System for observing fitness instruction time.
Journal of Teaching in Physical Education, 11, 195-205.
Moore, L. V, & Diez Roux, A. V. (2006). Associations of
neighborhood characteristics with the location and type
of food stores. American Journal of Public Health, 96(2),
325-31.
Narayan, K. M., Boyle, J. P., Thompson, T. J., Sorensen,
S. W., & Williamson, D. F. (2003). Lifetime risk for diabetes mellitus in the United States. Journal of the American
Medical Association, 290(14), 1884-90.
National Institute of Child Health & Human Development. (2005). Media Smart Youth: Eat, Think, and Be
Active! Retrieved February 25, 2007, from http://www.
nichd.nih.gov/msy/msy.htm.
Nicklas, T. A., Elkasabany, A., Srinivasan, S. R., & Berenson, G. (2001). Trends in nutrient intake of 10-year-old
children over two decades (1973-94) : The Bogalusa
Heart Study. American Journal of Epidemiology, 153(10),
969-77.
Winter 2007
Nord, M., Andrews, M., & Carlson, S. (2005). Household food insecurity in the United States, 2004. USDA
Economic Research Service, Economic Research Report
Number 11.
Potts-Datema, B. (2004). Healthy kids­—Healthy adults:
Teaching kids how to live a healthy life. Retrieved September 20, 2007, from http://www.nasbe.org/publications/
Calories_In_Calories_Out/PDF%20Documents%20for
%20web/Mr.%20Bill%20Potts-Datema%20-%20Healthy
%20Kids%20Healthy%20AdultsbTeaching%20Kids%20
How%20to%20Live%20a%20Healthy%20Life.pdf.
Quaid, L. (2006). Government adding fruits and vegetables to WIC moms’ shopping list. Retrieved September
20, 2007, from http://www.dhs.ca.gov/director/owh/
owh_main/pubs_events/news_articles/well_women/
08.2006wicfood.pdf.
Razak, F., Anand, S. S., Shannon, H., Vuksan, V., Davis,
B., Jacobs, R., Teo, K. K., et al. (2007). Defining obesity cut points in a multiethnic population. Circulation,
115(16), 2111-2118.
Rees, R., Kavanagh, J., Harden, A., Shepherd, J., Brunton, G., Oliver, S., Oakley, A. (2006). Young people
and physical activity: A systematic review matching
their views to effective interventions. Health Education
Research, 21(6), 806-825.
Ritenbaugh, C., Kumanyika, S.K, Jeffrey, R.W., Morabia,
A., & Antipatis, V.J. (1999). Caught in the causal web: A
new perspective on social factors affecting obesity. Healthy
Weight Journal, 13, 88-89.
Robert Wood Johnson Foundation. (2007). Program
areas: Childhood obesity. Retrieved September 20, 2007,
from http://www.rwjf.org/programareas/programarea.
jsp?pid=1138.
Romero-Corral, A., Montori, V. M., Somers, V. K.,
Korinek, J., Thomas, R. J., Allison, T. G., et al. (2006).
Association of bodyweight with total mortality and with
cardiovascular events in coronary artery disease: A systematic review of cohort studies. Lancet, 368(9536), 666-78.
Sallis, J.F., & Glanz, K. (2006). The role of built environments in physical activity, eating, and obesity in childhood. The Future of Children, 16(1), 89-108.
Sallis, J.F., McKenzie, T.L., Alcaraz, J.E., Kolody, B.,
Faucette, N., Hovell, M.F. (1997). The effects of a 2-year
physical education program (SPARK) on physical activity
and fitness in elementary school students. Sports, Play
and Active Recreation for Kids. American Journal of Public Health, 87(8), 1328-34.
21
Salmon, J., & Timperio, A. (2007). Prevalence, trends
and environmental influences on child and youth physical
activity. Medicine and Sport Science, 50, 183-99.
Urban Nutrition Initiative. (2007). University of Pennsylvania Center for Community Partnerships. Retrieved
March 20, 2007, from http://www.urbannutrition.org.
Schlosser, E. (2001). Fast food nation: The dark side of the
all-American meal. New York: Houghton Mifflin Company.
Wang, Y., & Beydoun, M. A. (2007). The obesity epidemic in the United States—Gender, age, socioeconomic,
racial/ethnic, and geographic characteristics: A systematic review and meta-regression analysis. Epidemiologic
Reviews. Retrieved June 21, 2007, from http://epirev.
oxfordjournals.org/cgi/reprint/mxm007v1.
Schoonover, H., & Muller, M. (2006). Food without
thought: How U.S. policy contributes to obesity. Retrieved
January 20, 2007, from http://www.iatp.org/iatp/publications.cfm?accountID=258&refID=80627.
Schwartz M.B., & Brownell K.D. (2007). Actions necessary to prevent childhood obesity: creating the climate for
change. Journal of Law, Medical & Ethics, 35(1):78-89
Staunton, C. E, Hubsmith, D., & Kallins, W. (2003).
Promoting safe walking and biking to school: The Marin
County success story. American Journal of Public Health,
93(9), 1431-4.
Strauss, R. S., & Pollack, H. A. (2003). Social marginalization of overweight children. Archives of Pediatric and
Adolescent Medicine, 157, 746-52.
United States Department of Health & Human Services.
(2007). The surgeon general’s call to action: Overweight
and obesity at a glance. Retrieved September 20, 2007,
from http://www.surgeongeneral.gov/topics/obesity/
calltoaction/fact_glance.htm.
Wang, Y., Zhang, Q. (2006). Are American children
and adolescents of low socioeconomic status at increased
risk of obesity? Changes in the association between
overweight and family income between 1971 and 2002.
American Journal of Clinical Nutrition, 84(4), 707-16.
Weiss, R.I., & Smith, JA. (2004). Legislative approaches
to the obesity epidemic. Journal of Public Health Policy,
25(3-4), 379-90.
Wiecha, J. L., Peterson, K. E., Ludwig, D. S., Kim, J.,
Sobol, A., & Gortmaker, S. L. (2006). When children eat
what they watch: Impact of television viewing on dietary
intake in youth. Archives of Pediatric and Adolescent
Medicine, 160(4), 436-42.
22 Perspectives on Childhood Obesity Prevention: Recommendations from Public Health Research and Practice
Appendix I: Reports Reviewed
Bolen, E, & Hecht, K. (2003). Neighborhood groceries:
New access to healthy food in low-income communities. San
Francisco, CA: California Food Policy Advocates.
Budd, G. M., & Volpe, S. L. (2006). School-based obesity prevention: Research, challenges, and recommendations. Journal of School Health, 76(10), 485-95.
Centers for Disease Control and Prevention. (1996).
Guidelines for school health programs to promote
lifelong healthy eating. Morbidity and Mortality Weekly
Report 45, no. RR-9,1-41.
Ebbeling, C. B., Pawlak, D. B., & Ludwig, D. S. (2002).
Childhood obesity: Public-health crisis, common sense
cure. Lancet, 360(9331), 473-82.
Hill, J. O., & Trowbridge, F. L. (1998). Childhood obesity: Future directions and research priorities. Pediatrics,
101(3), 570-574.
Kimm, S. Y. S., & Obarzanek, E. (2002). Childhood
obesity: A new pandemic of the new millennium.
Pediatrics, 110(5), 1003-1007.
Koplan, J. P., Liverman, C. T., & Kraak, V. I,; Committee
on Prevention of Obesity in Children and Youth. (2005).
Preventing childhood obesity: Health in the balance.
Journal of the American Dietetic Association, 105(1):131-8.
Flynn, M. A., McNeil, D. A., Maloff, B., Mutasingwa,
D., Wu, M., Ford, C., & Tough, S. C. (2006). Reducing
obesity and related chronic disease risk in children and
youth: A synthesis of evidence with “best practice” recommendations. Obesity Review, 7(Suppl 1), 7-66.
Foxhall, K. (2006). Beginning to begin: Reports from
the battle on obesity. American Journal of Public Health,
96(12), 2106-2112.
Institute of Medicine. (2005). Preventing childhood
obesity: Health in the balance. Washington, DC: National
Academies Press.
Institute of Medicine. (2007). Progress in preventing childhood obesity: How do we measure up? Washington, DC:
National Academies Press.
Story, M., Kaphingst, K. M., & French, S. (2006). The
role of schools in obesity prevention. The Future of Children,16(1),109-42.
Wechsler, H., McKenna, M. L., Lee, S. M., & Dietz, W.
H. (2004). The role of schools in preventing childhood
obesity. The State Education Standard, 5(2), 4-12.
Appendix II: Key Consultants
Janice Bowie, PhD, Assistant Professor, Department of
Health, Behavior, and Society, Johns Hopkins Bloomberg School of Public Health
Margarita Treuth, PhD, Associate Professor, Department
of International Health, Division of Human Nutrition,
Johns Hopkins Bloomberg School of Public Health
Benjamin Caballero, MD, PhD, Professor, Department
of International Health, Division of Human Nutrition,
Johns Hopkins Bloomberg School of Public Health
Lara Trifiletti, PhD, Assistant Professor, Center for Injury
Research and Policy, Columbus Children’s Hospital,
Ohio State University
Penny Gordon-Larsen, PhD, Assistant Professor, Department of Nutrition, University of North Carolina
School of Public Health
David Wallinga, MD, MPA, Director of the Food and
Health Program, Institute for Agriculture and Trade
Policy
Shiriki Kumanyika, PhD, Professor of Epidemiology,
University of Pennsylvania School of Medicine
Youfa Wang, PhD, Assistant Professor, Department of
International Health, Division of Human Nutrition,
Johns Hopkins Bloomberg School of Public Health
Leslie Lytle, PhD, Professor, Division of Epidemiology
and Community Health, University of Minnesota
Felicity Northcott, PhD, Lecturer, School of Arts & Sciences, Women’s Studies, Johns Hopkins University
Winter 2007
23