Does diet contribute to socioeconomic differences in the prevalence of obesity among Indian adolescents?

BackgroundIn India, the risk of obesity in adolescents between 10 and 19 years of age increases with socioeconomic advantage. Diet is a contributing factor to obesity, and obesity is a key risk factor for cardiovascular diseases (CVDs). However, the contribution of diet to socio-economic inequalities in overweight or obesity remains unclear. AimTo assess the mediating role of diet in the association between socioeconomic status (SES) and obesity among Indian adolescents. Data & MethodsData were obtained from the Comprehensive National Nutrition Dataset survey, a cross-sectional sample of the Indian adolescent population (N=35,830). Maternal educational attainment and household wealth index are used as proxies for SES. Diet quality was estimated using the Dietary Diversity Score (DDS) based on reported weekly intake of different categories of food. BMI for age Z-scores was used as a marker for obesity. Cross-section mediation was applied to estimate the proportions of obesity mediated by diet quality. Robustness checks were conducted by using alternative measures of diet quality. ResultsThe log-odds of obesity were estimated to rise by 0.603 (95% CI: 0.334,0.926) and 0.714 (95% CI: 0.573, 0.865) in rural and urban adolescents, respectively, with higher levels of maternal education (post-secondary or above), compared to those from lower maternal education (secondary or below). In wealthier adolescents (from middle-, rich-, richest quintiles), the log-odds of obesity were estimated to rise by 0.710 (95% CI: 0.529, 0.891) and 1.325 (95% CI: 0.924, 0.1.726) in rural and urban adolescents, respectively, compared to poorer adolescents (from poorest and poor quintiles). The proportion of the association mediated by diet varied between <1% and over 4%. ConclusionsThe findings suggested that diet quality mediates socio-economic inequalities in obesity among Indian adolescents, but only a small proportion. Therefore, differences in diet quality might not be the primary route by which SES translates into differences in risk for obesity among Indian adolescents. Focussing on improving diet quality and other risk factors (behavioural, environmental, demographic, socio-cultural) could prevent obesity among Indian adolescents and, therefore, the future burden of CVD in India.