Ononamadu C.J
Nigeria Police Academy, Nigeria
Title: Performance of anthropometric indices of obesity in predicting risk of hypertension and prehypertension in a Nigeria
Biography
Biography: Ononamadu C.J
Abstract
Background: Obesity is a well-established risk factor of hypertension and some other cardiometabolic disorders. However, the best anthropometric index of obesity that predicts hypertension and related conditions remains controversial and inconclusive owing to some factors.
Objective: This study compared the performances of eight (8) anthropometric measures of obesity- Body Mass Index (BMI), Ponderal Index (PI), Waist Circumference (WC), Hip Circumference (HC), Waist- Hip Ratio (WHR), Waist–Height Ratio (WHtR), Body Adiposity Index (BAI) and Conicity Index (CI) in predicting risk of hypertension and prehypertension.
Methods: This community based cross sectional study was conducted in Anambra State, South Eastern Nigeria from 2012-2013. A total of nine hundred and twelve persons (436 male and 476 female) drawn from three (3) major cities (Awka, Onitsha and Nnewi) in the state participated in the study. Information on demography and life style were obtained using a well-structured and validated questionnaire. The Systolic/Diastolic Blood pressure and anthropometric measurements were taken by well-trained personnels. The resulting data were analyzed using descriptive statistics, Logistic Regression, Poisson regression and Receiver Operative Curve (ROC) analysis.
Result: The mean values of all the anthropometric indices studied increased from Normotension, through Prehypertension to Hypertension in both sexes. BMI, WC, HC and CI were significantly higher (p<0.05) in males than the females. All the anthropometric indices studied were significantly (p<0.001 except for CI) correlated with systolic and diastolic blood pressure. BMI, WHtR, WC and PI (with higher correlation coefficients for Blood pressure) were the best predictors of hypertension and prehypertension in the study - BMI (Cutoff=24.49, AUC=0.698; Cutoff=23.62; AUC=0.659), WHtR (Cutoff=0.55, AUC=0.682; Cutoff=0.5; AUC=0.636), WC (Cutoff=91.44, AUC=0.692; Cutoff=82.55; AUC=0.645), PI (Cutoff=14.45, AUC=0.670; Cutoff=13.69; AUC=0.639), in male and BMI (Cutoff=24.44, AUC=0.622; Cutoff=28.01, AUC=0.609), WHtR (Cutoff=0.51, AUC=0.624; Cutoff=0.6; AUC=0.572), WC (Cutoff=96.62, AUC=0.616; Cutoff=96.52; AUC=0.584), PI (Cutoff=16.38, AUC=0.619; Cutoff=17.65; AUC=0.599), in female for hypertension and prehypertension respectively. In predicting hypertension risk, WC and WHtR did not perform significantly different from BMI and did not significantly improve the performance of BMI in models when added using our decision rule. While in predicting prehypertensive risk, BMI and WC were better off. CI had a very poor discriminatory power for both conditions in this study.
Conclusion: BMI, WHtR, WC and PI emerged the best predictors of hypertension risk and BMI, WC and PI for prehypertension in this study. The anthropometric indices of Obesity, WHtR and WC did not outperform or add to the performance of the anthropometric index of general Obesity, BMI, which is the most widely used anthropometric index. Thus, we recommend the simultaneous but independent use of BMI and either of WC or WHtR for predicting hypertension and BMI and WC for prehypertension risk bearing in mind that both types of index (abdominal and general obesity) account for different form of obesity.