Adolescent obesity is one of the most serious public health challenges of the 21st century having high prevalence rate in low- and middle-income countries, including in Asia. The relationship between BMI and body fat percentage (BF %) has been studied in various ethnic groups to estimate the ability of BMI to predict adiposity. Accuracy of obesity screening by commonly used BMI criteria is unclear in young south Indian population.
Materials and method: A total of 2212 participant (1320 males and 892 females) mean age was 11.5±1.6 years. BMI and BF% were recorded, the latter was determined by bioelectrical impedance analysis (BIA). Height and weight were measured and BMI was calculated (kg/m2)). A comparison between study population and previously available nationally representative (1989) data was performed for each age-sex group. WHO cut-off values were used and their respective status was assigned. The prevalence of overweight and obesity was expressed in percentages
Results: The prevalence of overweight and obesity was found to be 21.6% and 10.4%, respectively as per BMI category, while according to BF%, it was 17.0% and 10.9% respectively and the mean differences were found to be statistically significant (P=0.001. The fat percentages in girls were higher than in boys. BMI noted to increase with age in young in both boys and girls. This curvilinear effect was more significant in females (R2 = 0.27, R2 change = 0.058, SEE 11.5%) (p = <0.000) compared to males (R2 = 0.89, R2 change = 0.009, SEE 13.7%) (p = ≥0.05). Though females had a higher mean BMI values than males it was statistically insignificant (p ≥0.05). There was a positive linear correlation between BMI-BF% in both sex (males r =0.47, females r =0.64; p < 0.001).
Conclusion: The finding from our studies firstly provides the baseline value of the BMI and BF% in school going children in Kerala and BMI can also be used to evaluate the body fat percentage of the participants.