Comparing the Accuracy of Waist-Hip Ratio Calculation by the BIA device versus the Manual Method

Nowadays, the Waist-Hip Ratio is considered one of the most important indices in predicting the risk of cardiovascular diseases. The usual method for calculating this index is by measuring the waist and hip circumferences with a measuring tape. However, bioelectrical impedance analysis (BIA) devices are also capable of calculating this ratio. Hence, the goal of this study was to calculate this ratio with the BIA device and to compare it with the manual method done with measuring tape. A cross-sectional study was conducted on 270 individuals attending the Sports Medicine Department of Taleghani Hospital. Height, weight, waist and hip circumference were measured, and the body mass index (BMI) and waist-hip ratio (WHR) were calculated. Using the BIA technique, the body fat percentage (BFP) and WHR were calculated. The absolute and difference percentage between the values calculated by the device and measuring tape were calculated and the determinant factors of this difference were examined. The mean absolute difference between the two methods was 0.054 and the difference percentage was 0.064. Kappa’s correlation coefficient between the two variables was 0.024, which indicates poor correlation between the findings of the two methods. Based on linear regression analysis, BFP, height, BMI, and total body water (TBW) significantly affected the difference percentage. On the contrary, age, waist circumference, hip circumference, and absolute body fat did not have such an effect. The absolute difference was 0.069 in women and 0.05 in men, which was statistically significant (p = 0.025). Taking the manual waist-hip ratio method as the gold standard, the BIA method lacks adequate accuracy. Many variables such as, gender, BFP, TBW, BMI and height affect the accuracy of this method. Hence, until this technique is modified based on the aforementioned variables, we recommend avoiding the application of this method for WHR calculation.