Relationship of Waist Circumference, Waist Hip Ratio and Body Mass Index as Predictors of Obesity in Adult Nigerians

Abstract

Body Mass Index (BMI) has been considered a gold standard for defining overweight and obesity. BMI is an indicator of overall adiposity while Waist Circumference (WC) and Waist-to-Hip Ratio (WHR) are indicators for abdominal adiposity. To determine which of these indices-WC and WHR compared with BMI as the gold standard, is the best predictor of obesity in healthy adult Nigerians. Four hundred apparently healthy civil servants were recruited for the study by stratified random sampling. WC, WHR and BMI were determined using standard methods. Data were available for 400 healthy subjects (196 males and 204 females). WC was found to have a strong predictive capacity for obesity but this was only in female subjects (sensitivity 100%). The Negative predictive value was also 100% which implies accurate exclusion of female subjects who don’t have obesity. WHR showed poor predictive ability for obesity in both sexes (Positive predictive value 33.3% in male and 54.8% in female) though sensitivity and negative predictive value were relatively high and better amongst the females than male. In women, significant correlation exist between BMI and WC (p<0.001), BMI and WHR (p<0.01), WC and WHR (p<0.01) whereas, in men, the correlation was only significant for BMI and WC (p<0.01). This study strongly suggests that WC has a better predictive index for obesity than WHR.