Measures of obesity and cardiovascular risk among men and women

Objectives This study examined associations between anthropometric measures (body mass index, waist circumference, waist-to-hip ratio, waist-to-height ratio [WHtR]) and risk of incident cardiovascular disease (CVD) (including non-fatal myocardial infarction, nonfatal ischemic stroke, and cardiovascular death). Background Controversy exists regarding the optimal approach to measure adiposity, and the utility of body mass index has been questioned. Methods Participants included 16,332 men in the Physicians' Health Study (mean age 61 years in 1991) and 32,700 women in the Women's Health Study (mean age 61 years in 1999). We used Cox proportional hazards models to determine relative risks and 95% confidence intervals (CIs) for developing CVD according to self-reported anthropometric indexes. Results A total of 1,505 CVD cases occurred in men and 414 occurred in women (median follow-up 14.2 and 5.5 years, respectively). Although WHtR demonstrated statistically the strongest associations with CVD and best model fit, CVD risk increased linearly and significantly with higher levels of all indexes. Adjusting for confounders, the relative risk for CVD was 0.58 (95% CI: 0.32 to 1.05) for men with the lowest WHtR (< 0.45) and 2.36 (95% CI: 1.61 to 3.47) for the highest WHtR (>= 0.69; vs. WHtR 0.49 to < 0.53). Among women, the relative risk was 0.65 (95% CI: 0.33 to 1.31) for those with the lowest WHtR (<0.42) and 2.33 (95% CI: 1.66 to 3.28) for the highest WHtR (>= 0.68; vs. WHtR 0.47 to <0.52). Conclusions The WHtR demonstrated statistically the best model fit and strongest associations with CVD. However, compared with body mass index, differences in cardiovascular risk assessment using other indexes were small and likely not clinically consequential. Our findings emphasize that higher levels of adiposity, however measured, confer increased risk of CVD.