Changes in body composition and cardiometabolic risk among black South African adults

Background and objectives: \nObesity-related health risk may \ndiffer by ethnicity at the same body mass index (BMI). The objectives of this study were too determine the predictive value of the \nWorld Health Organization (WHO) overweight cut-point of BMI \nof 25 kg.m2 in men and women, respectively, to identify 10-year \ncardiometabolic risk and to determine optimal male (M) and female (F) BMI cut-points to identify 10-year cardiometabolic risk. \nMethods: \nIn the longitudinal PURE study of healthy black \nSouth Africans (n=2010), aged 30-90 years in 2005, demographic, lifestyle and anthropometric measures were taken and blood \npressure, fasting serum triglycerides, high-density lipoprotein \n(HDL)-cholesterol and blood glucose were measured. Three or \nmore risk factors according to international metabolic syndrome \n(MetS) criteria (fasting plasma glucose >5.6 mmol/L /oral hypoglycemic drugs, systolic blood pressure (SBP) >130 and/or diastolic blood pressure (DBP) >85 /anti-hypertensive drugs, serum \nTG >1.7 mmol/L, HDL-cholesterol <1 mmol/L M /<1.3 mmol/L \nF) and waist circumference (WC) above sex-specific cut-points \n(>94cm M/ >80cm F) in 2015 were defined as elevated cardiometabolic risk. \nResults: \nParticipants with WC above sex-specific cut-points \nin 2005 had significantly higher odds of having the MetS in 2015 \n(odds ratio, OR = 6.99, 95% CI 5.01, 9.75). Participants with BMI \nin the overweight/obese range (BMI > 25 kg/m2) in 2005 had significantly higher odds of having the MetS in 2015 (OR = 6.38, 95% \nCI 4.55, 8.94). Receiver Operating Characteristic curves to identify a sex-specific optimal BMI cut-point associated with increased \n10-year risk indicated a BMI cut-point of 23.3 kg/m2 in men and \n24.6 kg/m2 in women. A BMI cut-point of 30 kg/m2 had poor \ndiagnostic performance. WC cut-points to predict 10-year risk of \nMetS were 78.0 cm in women and 84.0 cm in men. All cut-points \nwere lower than international proposed cut-points for adiposity. \nConclusions: \nBaseline BMI and WC were significantly associated with increased cardiometabolic risk after follow-up. The \npredictive value of the WHO overweight cut-point of body mass \nindex (BMI > 25 kg/m2) was similar to the new sex-specific cutpoints (23.3 kg/m2 for men, 24.6 kg/m2 for women), but a BMI of \n30 kg/m2 had poor diagnostic ability