Body mass index or body fat! which is a better obesity scale for Pakistani population?

Objective: To compare two methods of classifying obesity based on body mass index and body fat percentage.

Methods: The cross-sectional study was conducted from November 2012 to August 2013 at Jinnah Postgraduate Medical Centre, Karachi. Male and female volunteers between the ages 15-65 years were selected using simple random sampling. They were classified into different groups for body mass index and body fat percentage measured through bioelectrical impedance scale. The subjects were sub-grouped into underweight, normal weight, overweight and obese. SPSS 11 was used for statistical analysis.

Results: The mean age of the 828 healthy volunteers was 25.67±10.10 years. A total of 552(66.6%) subjects had a higher body fat percentage and were misclassified by body mass index. Only 276(33.3%) subjects had body fat percentage values corresponding to the body mass index classification. The difference in terms of categorising obesity was highly significant (p<0.001).Both body mass index and body fat percentage showed positive correlation with age (r=0.144; p=0.001) (r=0.261; p=0.001) and weight (r=0.578; p=0.001) (r=0.444; p=0.001) respectively. Moreover body fat percentage showed a significant positive association with gender (r=0.109; p=0.027) whereas BMI did not.

Conclusions: Body fat percentage should be incorporated for a better understanding as well as categorising of obesity.