The Consideration of Validation on the Relative Weight Indices Derived from Body Weight and Height

PURPOSE: This study aimed to consider the validity of relative weight indices, which are used to compare people of different heights.METHODS: Cross-sectional analyses were conducted using the 2017-2021 “National Fitness Award” in South Korea. Males (n=77,705) aged 18-65 years and females (n=84,641) were included. Three indices [I₁=kg/m, I₂=kg/m^{2/sup>, and I₃=kg/m3] and I₄ [I₄=kg/ m2], which simply reduce the standard error of I₁, were analyzed. Pearson's correlation analysis was conducted to determine an index that was highly correlated with weight and was independent of height. Furthermore, an index that was highly correlated with the body fat percentage was considered. The linear relationship between height and the indices was confirmed using regression analysis. The n value of the index (kg/mn), which provides the same value for all height ranges, was derived by regression analysis between weight and height.RESULTS: The correlation analysis between height and the indices described I₂ (r=-.009, p<.05) as the most suitable for males. The I₁ and I₄ (r=-.049, p<.01) were appropriate for females. Weight showed a significant correlation with all indices. The association between body fat percentage and I₃ showed a high correlation in both males (r=.722, p<.01) and females (r=.734, p<.01). Regression analyses represented I₂ (B=-.005, p<.05) suitability for males. For females, I₄ (B=.022, p<.01) was replaceable.CONCLUSIONS: The results of this study suggest that I₂ (kg/m2) is appropriate for males. The I₄ (kg/m2) was applicable to females. The I₃ (kg/m3) showed the strongest correlation with body fat percentage in both males and females.}