Associate Professor Addis Ababa University Addis Ababa, Adis Abeba, Ethiopia
Objectives: To evaluate the performance a new anthropometric index – weight adjusted for waist-circumference to height ratio (W-WHR) – as a predictor of metabolic disfunction among adults 18-64 years in Addis Ababa, Ethiopia; and compare its performance with other commonly used indices.
Methods: The study was conducted using the data of 600 randomly selected adults. The study subjects completed blood pressure, blood glucose, lipid, and standardized anthropometric measurements. The performance of the index to correctly classify elevated cholesterol ratio, hypertension and hyperglycaemia was assessed using ROC analysis. Area Under the Curve (AUC) with 95% confidence interval (CI) was used as an overall summary of diagnostic accuracy and compare the performance of 13 indices. The indices considered in the study were W-WHR, BMI, Rohrer's Index, Conicity index (CI), Body adiposity index (BAI), Body roundness index (BRI), Abdominal volume index (AVI), Body shape index (BSI), Weight-adjusted-waist index (WWI), Waist-to-height ratio (WHR), % body fat, Waist circumference (WC), Waist-to-hip ratio. Optimal cut-off value was determined using the Youden’s index.
Results: The mean (± SD) age of the participants was 31.2 (± 11.4) years and male-to-female ratio was 0.93. ROC analysis (AUC, 95% CI) suggested W-WHR has acceptable accuracy to predict elevated cholesterol-to-HDL ratio (0.80, 0.76 – 0.84), hypertension (0.74, 0.70 – 0.78), hyperglycemia (0.76, 0.70 – 0.82) and occurrence of one of the three outcomes (0.79, 0.75 – 0.83). For predicating elevated cholesterol ratio, AUC was highest for W-WHR (AUC=0.80), followed by AVI (AUC=0.78) and WC (AUC=0.78). For hypertension, W-WHR (AUC=0.74) and WC (AUC=0.74) had better performance. For hyperglycemia, waist-to-height ratio (AUC=0.80) and Body roundness index (BRI) (AUC=0.80) had the highest AUC. For the joint outcome, W-WHR had the best AUC of 0.79, along with AVI (AUC=0.78) and WC (AUC=0.78). Sex-specific analysis indicated most the indices have relatively better performance in men than in women. Cutoff value of 30.5 maximized both sensitivity and specificity of the index at the same time.
Conclusions: W-WHR is a useful index for predicting metabolic disfunction among adults 18-64 years and performs better than the other existing indices, especially in men.
