ui
ASSESSMENT OF OVERWEIGHT AND OBESITY
h
an
The
Heart
Foundation
a
Te H o t u M
na
wa
W
Kg
(st/lb)
This resource is inappropriate for use with:
l children or adolescents under the age of 18 years
l very muscular people
l pregnant women
l those who are very short (less than 150cm) or very tall (greater than 190 cm)
Kg/m2
32
120
(18.2)
30
CALCULATIONS
BODY MASS INDEX (BMI)
110
(17.4)
Metric conversion formula = Weight (kg) / height (m)2
Example of BMI calculation:
A person who weighs 78 kilograms and is 177 centimetres tall has a BMI of 25:
Weight (78kg) / height (1.77m x 1.77m) = 24.9
100
(15.10)
25
90
(14.2)
80
(12.8)
Overweight
18.5
70
(11.0)
60
(9.6)
Healthy
BODY MASS INDEX IN KILOGRAMS PER METRE SQUARED
WEIGHT IN KILOGRAMS (STONES & POUNDS) — IN LIGHT CLOTHING WITHOUT SHOES
26
Obesity
Non-metric conversion formula = [weight (pounds) / height (inches)2] x 704.5
Example of BMI calculation:
A person who weighs 165 pounds and is 68 inches (or 5’8”) tall has a BMI of 25.1
{weight (165 pounds) / height (68 inches x 68 inches)} x 704.5 = 25.1
CLASSIFICATION OF OVERWEIGHT AND OBESITY
RISK OF TYPE 2 DIABETES AND
CARDIOVASCULAR DISEASE
BMI
(kg/m2)
Underweight
Healthy
Overweight
Obesity
50
(7.12)
40
(6.4)
<18.5
18.5 - 25
25 - 30
>30
Waist Circumference (cm)
Men £ 102cm
Women £ 88cm
> 102cm
> 88cm
—
—
Increased
High
—
Increased
High
Very High
Table adapted from: Preventing and Managing the Global Rpidemic of Obesity
Report of the World Health Organisation Consultation of Obesity. WHO, Geneva, June 1997.
Underweight
NOTES
30
(4.10)
l For Maori and Pacific Islands people the upper range for healthy weight and obesity
should be extended to 26kg/m2 and 32kg/m2 respectively.
140cm
(4’7”)
150cm
(4’11”)
160cm
(5’3”)
170cm
(5’7”)
180cm
(5’11”)
HEIGHT IN CENTIMETRES (FEET & INCHES) — WITHOUT SHOES
190cm
(6’3”)
l For Asion populations, BMI definitions should be adjusted downwards.
l The health risk from obesity may not be as strong in people over 75 years.
This chart is a guideline only and clinical judgement may be needed for some individuals.
BACKGROUND INFORMATION FOR THE HEALTH PROFESSIONAL
TREATMENT ALGORITHM*
1. The person’s risk status should be assessed by determining the degree of overweight or
obesity based on BMI. the degree of abdominal obesity based on waist circumference,
and the presence of concomitant risk factors or co-morbidities.
Patient Encounter
2. An increased waist circumference is independently associated with increased health risk
including people with a BMI less than 25kg/m².
Hx of ³ 25 BMI?
3. If the BMI is above 35kg/m² the waist circumference does not add significantly to the risk
estimation.
No
Yes
BMI
measured in past
2 years?
4. Waist circumference cut-off points can generally be applied to all adult ethnic groups
unless the person is very short (less than 150cm).
5. The relationship between BMI and health risk weakens with increasing age, especially over
75 years. This is partly explained by confounding factors (such as occult diseases, selected
survival and smoking).
• Measure weight,
height and waist
circumference
• Calculate BMI
BMI ³ 25 OR
waist circumference
>88cm (F)
>102cm (M)
6. At any given percentage of body fat, BMI is one or two units higher in Polynesians than in
New Zealand Europeans and these differences increase with increasing BMI.
Yes
Assess risk factors
No
Hx BMI ³ 25?
Yes
Clinician and patient
devise goals and
treatment strategy
for weight loss
and risk factor control
No
Yes
Yes
Does patient
want to lose
weight?
No
Brief reinforcement/
educate on weight
management
7. Asian ethnicity is associated with a smaller body frame and therefore BMI cut-offs should be
adjusted downwards, however, equivalent levels have not been determined.
BMI ³ 30 OR
{BMI 25 to 29.9 OR
waist circumference
>88cm (F) >102cm (M)}
AND
³ 2 risk factors
Advise to maintain
weight/address
other risk factors
Periodic Weight Check
Yes
Progress
being made/goal
achieved?
No
No
Maintenance counseling:
• Dietary therapy
• Behaviour therapy
• Physical activity
Assess reasons for
failure to lose
weight
Instructions for Measuring Waist Circumference
To define the level at which waist circumference is
measured, a bony landmark is first located. The
measuring tape is placed in a horizontal plane
around the abdomen at a level just above the
uppermost lateral border of the iliac crest. The plane
of the tape is parallel to the floor and the tape is
snugg, but does not compress the skin. The
measurement is made at a normal minimal
expiration.
Examination
Treatment
* This algorithm applies only to the assessment for overweight and obesity and subsequent
decisions based on that assessment. It does not reflect any initial overall assessment for other
conditions and diseases that the clinician may wish to do.
ADVANTAGES OF WEIGHT LOSS
• Lowering of elevated blood pressure in overweight and obese persons.
• Lowering of total cholesterol, LDL-cholesterol, and triglyceride, raising of low
HDL-cholesterol levels in overweight and obese persons with dyslipidaemia.
• Lowering of elevated blood glucose levels in overweight and obese persons
with type 2 diabetes.