BMI category-specific waist circumference thresholds based on cardiovascular disease outcomes and all-cause mortality: Tehran Lipid and Glucose Study (TLGS)

Abstract

Abstract Background Waist circumference (WC) is representative of abdominal visceral fat, which is strongly associated with cardiovascular disease (CVD) and its’ outcomes. We aimed to define WC thresholds predicting incident CVD and all-cause mortality within each body mass index (BMI) categories in Tehran Lipid and Glucose Study. Methods In this prospective cohort study, a total of 3344 men and 4068 women were followed up for 18 years. Participants were categorized based on BMI into BMI < 25, 25 < BMI < 30, and BMI > 30. The sex-specific WC cut-points within each group were estimated by the maximum value of Youden’s index based on incident CVD and all-cause mortality prediction. Results 667 and 463 CVD incidents (incident rate 3.1 to 4.5 in men and 1.1 to 2.6 in women per 1,000 person-years within BMI categories) and 438 and 302 mortalities (incident rate 2.1 to 2.7 in men and 1.2 to 1.4 in women per 1,000 person-years within BMI categories) were happened in men and women, respectively. WC thresholds were 82, 95, and 103cm based on incident CVD and 88, 95, and 103cm based on all-cause mortality among men in BMI < 25, 25 < BMI < 30, and BMI > 30, respectively. The respective values for women were 82, 89, and 100cm based on incident CVD and 83, 90, and 99cm based on all-cause mortality in BMI < 25, 25 < BMI < 30. Conclusion The BMI-specific WC thresholds given here can give clues to future studies to define more accurate incidence-based WC cut-offs as screening tools to better identify individuals at high risk of developing CVD.