BMI

Body mass index in
preschoolers
Melissa Wake and Sharon Foster
Centre for Community Child Health
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
The early 21st
Century provides
the most obesogenic
environment known
in the history of
mankind
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Energy
Energy balance
balance equation
equation
Metabolism
growth
REE
nutrition
In
Out
AEE
energy
storage
Physical activity
Centre for Community Child Health
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
- too many accelerators, not
enough brakes…
Unhealthy choices the default:
– High intake of energy-dense food
• Fast food outlets, energy-dense snacks, high sugar
drinks
• Low cost, large servings
– Reduced physical activity
• Transport systems and urban design that inhibit active
transport and recreation
– Swinburn & Egger bmj 2004;329:736-9
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Consequences of child overweight
Individual
• Increased risk adult obesity
• Impaired quality of life
• Increased physical morbidity and mortality
Society
• Increased health service utilization and reduced
working capacity
• For the first time in history we have a generation that
may be outlived by its parents
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Prevalen ce %
35
30
Australia
25
Brazil
20
Canada
15
China
10
Spain
5
UK
0
1970
USA
1980
1990
2000
Trends in prevalence of overweight in children, 1970-2000 (IOTF
criteria). Adapted from Lobstein et al, 2004.
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
LSAC: Prevalence (%) 2004
Not overw’t
(n= 3920)
All
Boys
Girls
79.3
80.9
77.6
Overweight Obese
(n= 756) (n= 258)
15.2
14.0
16.5
5.5
5.2
5.8
(-cf- 1995 National Nutrition Survey (532 4-6 yr olds):
13.4% boys, 19.5% girls overweight/obese)
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Why in M&CH Practice?
• Tertiary management not appropriate for a condition
affecting 20% of preschoolers!
• M&CH nurses see these children
• Preventive health care appropriate
• Appropriate forum for family-centred discussion…
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
…maternal & child health – 80% have at least one
parent who is also overweight/obese
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
BMI in primary care
• Primary care is a possible secondary prevention
setting for tackling childhood overweight
• NHMRC 2003 Clinical Practice Guidelines for
Management of Overweight and Obesity in Children
and Adolescents:
– Height & weight: measure at least bi-annually in all children
and adolescents as part of routine primary care
– BMI: standard measure of overweight and obesity for 2 -18
year olds. Compare child’s BMI with CDC BMI-for-age and
gender percentile charts
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
http://www.cdc.gov/growthcharts/
CDC 2000
(for US population)
BMI = ht/wt2
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Who does it?
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Not RCH!!
102 children: median age (range)
4.6 (2-12)
Weight recorded
102 (100%)
Height recorded
2 (2%)
BMI recorded
0
12 overweight/obese children:
Surprised child overweight/obese
5
Can recall when last weighed/measured
8
Previous suggestion overweight
2
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Parental attitudes n =12
All children admitted to the RCH should:
Be weighed
Be measured
11
9
Have BMI calculated
8
Hospital should take action if child
all
overweight
Parents should always be told if child
8
overweight
Majority comfortable with MCHN, GP, doctor or
nurse at hospital addressing child overweight
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Do general practitioners routinely weigh, measure
and calculate BMI for 5–10 year old children?
Routinely does this
activity at least annually
If part of routine practice,
for what proportion of
children?
N (%)
(Median)
Weigh the child
15 (44)
55%
Measure the child’s height
13 (38)
25%
1 (3)
90%
Weight
14 (41)
15%
Height
14 (41)
15%
2 (6)
65%
Practice
Calculate the child’s BMI
Plot the child’s centiles for:
BMI
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Do GPs have
accurate and
accessible
anthropometric
equipment?
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Stadiometers
• 34 (3 rigid; 9 fixed tape/chart; 22 pull
down tape)
• mean age: 7yrs (up to 34yrs)
• 2 serviced
• calibration (mean ± SD (range)):
92.68cm pole = 92.52 ± 0.8 (89.0 –
94.1)
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Scales
• 45 (6 beam/balance; 8 digital; 31
non-digital)
• Mean age: 5yrs (up to 22yrs)
• 4 serviced
• calibration (mean ± SD (range)):
0kg
0.1 ± 0.2 (-0.2 – 1.5)
20kg
19.7 ± 0.6 (17.5 – 21.0)
40kg
39.6 ± 0.9 (36.5 – 41.3)
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
80
Weight (kg) by GP scales (mean ±2SD)
20
30
40
50
60
70
Accuracy of GP
scales against
calibration (true)
weights, shown as
mean ± 2SD error
bars against each
true weight.
10
Digital – left
Non-digital - right
10
20
30
40
50
60
True Weight (kg)
70
80
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
http://www.cdc.gov/growthcharts/
CDC 2000
(for US population)
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
True BMI
Largest BMI
Smallest BMI
CDC growth chart for girls 2-20 years18
Discrepancy
between true
BMI percentile
and the largest
and smallest BMI
percentiles
calculated using
the most
inaccurate
anthropometric
equipment at
participating
practices, for
hypothetical six
and nine year old
girls with a true
BMI of 17 kg/m2
(weight 30kg,
height 133cm)
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
MCH nurses 2006 (n=175)
Always/almost always…(%)
Weigh
Measure
2 yr
84
85
3 yr
69
71
4 yr
38
37
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Scales (%)
Type
Location
Age (years)
When serviced
Digital
81
Bathroom
6
Beam balance
12
Tile/hard floor
39
Carpet
54
Other
7
1-2
16
3-4
20
≥5
35
No idea
29
2005-6
68
2000-04
3
Don’t know
29
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Stadiometers (%)
Type
Age (years)
When last
serviced/ checked
Rigid stand-alone
23
Pull-down on wall
63
Tape/chart
10
Handheld yardstick
2
<1
6
1-5
36
≥5
55
No idea
3
2005-6
2000-4
9
5
Not since I’ve been here
31
Don’t know
55
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Measuring and BMI
Training for
None
7
measuring
Taught myself
16
During MCH course
70
Colleagues
15
Specific training (72-04)
6
Recording growth
Write weight
95
In CHR
Plot weight
80
(always/almost
Write height
95
always)
Plot height
80
Calculating BMI?
Don’t
Paper/pencil
83
2
Calculator
6
Nomogram/calculator
3
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Formula for BMI?
Wt x ht
Ht2/wt
Ht/wt
?
(Wt x ht)/
age
Wt2/ht
Wt/ht
Wt x ht2
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Formula for BMI?
Wt x ht
Ht2/wt
Ht/wt
Wt/ht2
(Wt x ht)/
age
Wt2/ht
Wt/ht
Wt x ht2
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
US Preventive Services Task
Force
• Insufficient evidence for effectiveness of behavioural
counselling or other preventive interventions with
overweight children in primary care settings
• Available studies limited by small sample sizes, poor
generalisability, variable follow-up
• Research needed to provide:
– well-defined and effective approaches to screening in
children
– effective clinical approaches for prevention & treatment of
overweight in children in primary care
– Pediatrics July 2005 116:205-9
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Challenges
Mismatch:
NHMRC vs Practice (RCH, GPs,
guidelines
M&CH nurses)
Population risks vs Risks for individual child
Professional concern vs Effective strategies
Parent awareness of vs Concern about weight of
obesity epidemic
own child
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
PEAS Kids Growth Study
Parents of 64 overweight/obese 4 year olds:
• 17% reported concern that child currently
overweight
• Less concern for overweight boys than
overweight girls (6% vs 22%)
• 72% reported child similar weight to peers
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Current project (CCCH/DHS)
• Survey re current practice and needs
• Training package in calculation, use and
interpretation of BMI and BMI charts
• Approaches to raising and discussing
overweight/obesity in preschoolers
• Future: research into effective strategies
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)
Thank you!
•
•
•
•
•
Department of Human Services
LEAP project team (GP project)
Dr Karen McLean (RCH project)
PEAS Kids Growth Study Team
Longitudinal Study of Australian Children
• [email protected]
This document is managed by the Department of Education and Early Childhood Development, Victoria (as of 27 August 2007)

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