Measuring obesity among school-aged youth in India: a comparison of three growth references.

OBJECTIVE To compare three growth references that can be used to assess the weight status of school-aged youth living in India, with a particular focus on identifying overweight and obese youth. STUDY DESIGN Cross-sectional study. Kappa scores were used to measure agreement between growth references. Regression models were used to test for differences in weight status by grade level, gender, and school type, using each growth reference. SETTING Private (n=4) and Government schools (n=4) in Delhi, India. PARTICIPANTS Students (n=1818) in eighth and tenth grade attending the schools. MAIN OUTCOME MEASURES Weight status was derived using age- and gender-specific cut-points provided by: (a) a national growth reference specific to India; (b) an international reference recommended by the International Obesity Task Force (IOTF); and (c) a new international reference recommended by the World Health Organization (WHO). RESULTS The IOTF reference consistently classified participants in a lower weight status category, compared with the national reference (k=0.57) and the WHO reference (k=0.69). The agreement between the WHO and the national references was higher (k=0.84). CONCLUSIONS To date, all published studies of childhood obesity in India have used the IOTF reference, the national reference, or an old WHO reference to measure weight status among school-going youth. The new WHO reference may be a better choice. Compared to the IOTF reference, it does not appear to underestimate obesity and can still be used to compare trends, globally.