Purpose: The association of overall obesity and abdominal adiposity in predicting risk of all-cause mortality in white and black adults was compared.
Methods: This prospective study included a national sample of 3219 non-Hispanic white and 2,561 non-Hispanic black adults 30 to 64 years of age enrolled in the third National Health and Nutrition Examination Survey during 1988-1994. Multiple measures of adiposity were measured and calculated, including body mass index (BMI), waist circumference, waist-to-hip ratio (WHR), and waist-to-thigh ratio (WTR). Vital status was ascertained with the National Death Index through 2000.
Results: During 12 years of follow-up (51,133 person-years), 188 white and 222 black adults died. After adjustment for age, education, smoking, and existing disease, positive dose-response associations between WTR and mortality in both sexes and races, and WHR in white and black women were observed (p(trend) < 0.05 for all). These results were unchanged after additional adjustment for BMI. In contrast, BMI and waist circumference alone exhibited curvilinear-shaped associations with mortality. A higher WTR was associated with a higher risk of mortality among normal weight (BMI: 18.5-24.9 kg/m(2)) and obese (BMI: > or =30.0 kg/m(2)) white and black adults.
Conclusions: These results suggest ratio measures of abdominal adiposity, particularly WTR in both sexes and WHR in women, strongly and positively predict mortality, independent of BMI, among white and black adults. Furthermore, WTR offers additional prognostic information beyond that provided by BMI alone.