Relationship Between Body Mass Index and Waist Hip Ratio in Female Subjects

Wednesday, 1 August 2012

Youngmee Ahn, PhD, RN
Department of Nursing, Inha University, Incheon, South Korea
Sun-Ha Choi, PhD, RN
Department of Nursing, Gangneung-Wonju National University, Wonju Campus, Wonju, South Korea

Learning Objective 1: The learner will be able to calculate the BMI and WHR to assess obesity and body shape of human being.

Learning Objective 2: The learner will be able to understand interpret the BMI and WHR to assess body shape in respect of obesity.

Purpose: Body mass index (BMI) is feasible and popular to assess the degree of obesity. As an arithmetic index on proportion of weight and height, it may not highlight the body shape related to obesity. Waist to hip ratio (WHR) is an index to depict how body torso shape. There is a need to explore how the two indexes are related to each other as to various aged groups.

Methods: A cross sectional descriptive study was conducted to explore the relationship between BMI and WHR in 201 female subjects consisted of three aged groups of 62 school aged-children, 68 adolescents and 71 young adults. Height, weight and the circumference of waist and hip of each subject were manually measured using a scale and a ruler by the trained staffs in systemic manners. Then BMI and WHR were calculated from these measurements. 

Results: The mean BMI were 17.4 (SD 3.4), 21.6 (SD 2.8) and 21.4 (SD 2.6) and the mean WHR were 0.80 (SD 0.5), 0.72 (SD 0.04), and 0.74 (SD 0.38) for three groups retrospectively. There was a significant difference in BMI (F=42.905, p<.000) and WHR (F=57.380, p<.001) among three groups. The correlation coefficients between BMI and WHR showed .244, .431 and .419 for three groups retrospectively.

Conclusion: It is not certain which one is more feasible and valuable index to assess obesity when both BMI and WH are well correlated. Both indexes may generate more valuable information on the degree and nature of obesity when applied in both.