Cross-sectional reference values for BMI among Khasi tribal adolescents of Meghalaya, India

Body mass index (BMI) is a useful tool to assess nutritional status and may be applied to study undernutrition and overweight/obesity in distinct ethnic populations like Khasi tribal children to derive cross sectional reference values for undernutrition, overweight and obesity. Cross-sectional methods of anthropometric measurements in 957 Khasi children (467 boys, 490 girls) of age 11 to 17 years were used to derive BMI (kg/m2), which were compared with national and international standards. Smoothed Khasi specific BMI percentiles were generated by the LMS method and International Obesity Task Force (IOTF) criteria were applied as for Asian children. Mean BMI in Khasi children were below those of national and international reference standards. Girls achieved higher BMI in late adolescence, but boys remained thin throughout. Smoothed percentile charts were constructed for boys and girls and IOTF criteria for undernutrition, overweight and obesity were applied corresponding to 11, 77.4 and 90.5 percentiles for boys and 13.4, 74 and 91.2 percentiles for girls, respectively. Undernutrition was more prevalent in boys than in girls, particularly at age 14 and 15 years (p < 0.001). There was a small prevalence of obesity, 5.1% in boys and 9.5% in girls at age 17 years. BMI values in pubertal Khasi boys and girls are different from commonly used standards. BMI percentiles specific to Khasi children in puberty are advocated to track changing trends over time.