Waist to Hip for Measuring Obesity

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Hi folks:

Here is a new paper, just out, from the INTERHEART Study, which

maintains that waist to hip ratio is a far better measure than BMI

for risk of MI:

" Obesity and the risk of myocardial infarction in 27,000 participants

from 52 countries: a case-control study.

Summary

Background

Obesity is a major risk factor for cardiovascular disease, but the

most predictive measure for different ethnic populations is not

clear. We aimed to assess whether markers of obesity, especially

waist-to-hip ratio, would be stronger indicators of myocardial

infarction than body-mass index (BMI), the conventional measure.

Methods

We did a standardised case-control study of acute myocardial

infarction with 27 & #8200;098 participants in 52 countries (12 & #8200;461 cases

and

14 & #8200;637 controls) representing several major ethnic groups. We

assessed the relation between BMI, waist and hip circumferences, and

waist-to-hip ratio to myocardial infarction overall and for each

group.

Findings

BMI showed a modest and graded association with myocardial infarction

(OR 1·44, 95% CI 1·32–1·57 top quintile vs bottom quintile before

adjustment), which was substantially reduced after adjustment for

waist-to-hip ratio (1·12, 1·03–1·22), and non-significant after

adjustment for other risk factors (0·98, 0·88–1·09). For waist-to-hip

ratio, the odds ratios for every successive quintile were

significantly greater than that of the previous one (2nd quintile:

1·15, 1·05–1·26; 3rd quintile: 1·39; 1·28–1·52; 4th quintile: 1·90,

1·74–2·07; and 5th quintiles: 2·52, 2·31–2·74 [adjusted for age, sex,

region, and smoking]). Waist (adjusted OR 1·77; 1·59–1·97) and hip

(0·73; 0·66–0·80) circumferences were both highly significant after

adjustment for BMI (p<0·0001 top vs bottom quintiles). Waist-to-hip

ratio and waist and hip circumferences were closely (p<0·0001)

associated with risk of myocardial infarction even after adjustment

for other risk factors (ORs for top quintile vs lowest quintiles were

1·75, 1·33, and 0·76, respectively). The population-attributable

risks of myocardial infarction for increased waist-to-hip ratio in

the top two quintiles was 24·3% (95% CI 22·5–26·2) compared with only

7·7% (6·0–10·0) for the top two quintiles of BMI.

Interpretation

Waist-to-hip ratio shows a graded and highly significant association

with myocardial infarction risk worldwide. Redefinition of obesity

based on waist-to-hip ratio instead of BMI increases the estimate of

myocardial infarction attributable to obesity in most ethnic groups. "

Rodney.