Measures of abdominal adiposity and the risk of stroke: the MOnica Risk, Genetics, Archiving and Monograph (MORGAM) study.

BACKGROUND AND PURPOSE: Excess fat accumulates in the subcutaneous and visceral adipose tissue compartments. We tested the hypothesis that indicators of visceral adiposity, namely, waist circumference (WC), waist-to-hip ratio (WHR), and waist-to-height ratio (WHtR), are better predictors of stroke risk than body mass index (BMI).

METHODS: The association of BMI, WC, WHR, and WHtR with stroke was assessed in 31,201 men and 23,516 women, free of vascular disease at baseline, from the MOnica Risk, Genetics, Archiving and Monograph (MORGAM) study. During a mean follow-up of 11 years, 1130 strokes were recorded. Relative risks (95% CI) were calculated by Cox regression after stratification for center and adjustment for age, smoking, educational level, alcohol consumption, hypertension, diabetes, total cholesterol, high-density lipoprotein cholesterol, and BMI and model fit was assessed using log-likelihoods.

RESULTS: BMI, WC, WHR, and WHtR were associated with the risk of stroke in men. After full adjustment including BMI, the relative risks for stroke remained significant for WC (1.19 [1.02 to 1.34] per 1 SD increase in WC), WHR (1.14 [1.03 to 1.26]), and WHtR (1.50 [1.28 to 1.77]). Among women, the extent of the associations with stroke risk was similar for WHtR (1.31 [1.04 to 1.65]), WC (1.19 [0.96 to 1.47]), and WHR (1.08 [0.97 to 1.22]). Further analyses by World Health Organization obesity categories showed that WC, WHR, and WHtR were associated with the risk of stroke also in lean men and women (BMI<25 kg/m2), independently of confounders, cardiovascular risk factors, and BMI.

CONCLUSIONS: Indicators of abdominal adiposity, especially WHtR, are more strongly associated with stroke risk than BMI. These results emphasize the importance of measuring abdominal adiposity, especially in lean subjects.