Upper-Body Adiposity and Risk of Myocardial Infarction

BACKGROUND: The relation between obesity and coronary heart disease (CHD) has long been studied, but no convincing conclusion has been drawn. OBJECTIVE: To estimate the relative risk associated with upper-body adiposity which is at present believed to be a better predictor of CHD. DESIGN: This was a community-based case-control study. METHODS: We studied 338 consecutively admitted patients who had had their first acute myocardial infarction (AMI) and 662 community controls who had not suffered AMI selected as a random sample of adults living in the catchment area of the hospital. We defined three classes of body mass index (BMI) and waist: hip circumference ratio on the basis of tertiles of distribution for controls. Odds ratios (OR) were estimated using unconditional logistic regression. Separate models were built for men and women. RESULTS: In univariate analysis we found a higher risk of AMI for men and women with hypertension, dyslipidaemia, diabetes and lower levels of education, for older women, for male smokers and for men with family histories of CHD. Both for men and for women a higher BMI was associated with a slightly higher risk, whereas the adjusted risk of AMI increased with increasing waist: hip circumference ratio [for men OR (second tertile)= 2.5, 95% confidence interval (CI) 1.3-4.9 and OR (third tertile)= 11.1, 95% CI 6.0-20.6; for women OR (second tertile) = 3.0, 95% CI 0.6-14.8 and OR (third tertile) = 14.1,95% CI 3.2-62.7]. This relation held for each BMI class and was stronger for classes of lower BMI. CONCLUSIONS: Distribution of body fat rather than BMI is a strong marker of risk for AMI and there is a clear interaction between these two variables.