Body mass index and skinfold thickness measurements as indicators of obesity in adolescents

Abstract

objective : To assess prevalence of overweight and obesity in government and private school adolescents by using BMI and measurements of skinfold thickness as parameter of obesity and to evaluate diagnostic value of skinfold thickness measurement as compared to BMI in identifying overweight and obese adolescents. methods: This was questionnaire based, voluantary response prospective study. Data were collected from 600 adolescents aged between 10-19 years divided equally between government and private school of both genders. Height, weight and skinfold thickness (Triceps skinfold and Subscapular skinfold) were measured.BMI calculated. Prevalence of overweight and obesity were determined and TSFT and SSFT compared with BMI as obesity parameters. results: Prevalence of overweight and obesity were significantly less in government school adolescents as compared to private school (7% vs 21.67% and 3.33% vs 8.33% respectively)(p 0.001 significant). TSFT in comparison to BMI carried sensitivity 49.59%, specificity 100%, positive predictive value100%, negative predictive value 88.70% and efficacy 89.83%. SSFT in comparison to BMI carried sensitivity 41.32%, specificity 100%, positive predictive value 100%, negative predictive value 87.09% and efficacy88.17%. Correlation of BMI with TSFT(r=0.508) and SSFT(r=0.604) was significant (p 0.001).Correlation of TSFT and SSFT with age was not significant. Correlation of TSFT and SSFT with genders (in both boys and girls) was found significant (p 0.001). conclusion: BMI measures body weight. It cannot give accurate assessment of body composition or body fat. Skinfold thickness measurements are better predictors for body fat in both boys and girls which do not correlates with age.