Obesity in African women in the North West Province, South Africa is associated with an increased risk of non-communicable diseases: the THUSA study

Abstract

The objective of the present study was to assess the relationship between anthropometric measurements and risk factors for non-communicable diseases (NCD) in South African black women. A cross-sectional sample of 1040 apparently healthy black female volunteers, 15–70 years old, was recruited from thirty-seven randomly selected sites in the North West Province, stratified according to level of urbanisation. We analysed the association between BMI, waist:hip (WHR), waist circumference (WC) and skinfold measurements and the following risk factors for NCD: blood pressure, serum lipids, fasting serum glucose and insulin and plasma fibrinogen, by using age-adjusted correlation analyses and stepwise regression analysis. Of the subjects, 28·6 % were obese (BMI>30). After adjustment for age and smoking status, BMI correlated significantly with diastolic blood pressure ( r 0·21, P =0·037), serum triacylglycerols (TG) ( r 0·30, P =0·003), fasting glucose ( r 0·29, P =0·005) and log fasting insulin ( r 0·24, P =0·02). There was a significant negative correlation between BMI and HDL-cholesterol ( r -0·38, P <0·001). Similar but stronger correlations were found between both WC and WHR and these risk factors. Together with age, WC was a significant predictor of TG, HDL-cholesterol and fasting glucose in regression analysis, while subscapular skinfold was a significant predictor of diastolic blood pressure and fasting glucose concentration. Triceps skinfold was a significant predictor of total serum cholesterol, LDL-cholesterol, plasma fibrinogen and the insulin sensitivity index. Measures of obesity, particularly WC, are associated with the risk for NCD in black South African women, in which a high rate of obesity has been found.