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

Abstract

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/m2, 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.

Keywords

• body mass index
• relative weight index
• body fat percent
• standard weight
• obesity index