Socioeconomic inequality in childhood obesity and its determinants: a Blinder–Oaxaca decomposition

Abstract

ObjectiveChildhood obesity has become a priority health concern worldwide. Socioeconomic status (SES) is one of its main determinants. This study aimed to assess the socioeconomic inequality of obesity in children and adolescents at national and provincial levels in Iran. MethodsThis multicenter cross‐sectional study was conducted in 2011–2012, as part of a national school‐based surveillance program performed in 40,000 students, aged 6–18‐years, from urban and rural areas of 30 provinces of Iran. Using principle component analysis, the SES of participants was categorized to quintiles. SES inequality in excess weight was estimated by calculating the prevalence of excess weight (i.e., overweight, generalized obesity, and abdominal obesity) across the SES quintiles, the concentration index (CCI), and slope index of inequality (SII). The determinants of this inequality were determined by the Oaxaca Blinder decomposition. ResultsOverall, 36,529 students completed the study (response rate: 91.32%); 50.79% of whom were boys and 74.23% were urban inhabitants. The mean (SD) age was 12.14 (3.36) years. The prevalence of overweight, generalized obesity, and abdominal obesity was 11.51%, 8.35%, and 17.87%, respectively. The SII for overweight, obesity and abdominal obesity was −0.1, −0.1 and −0.15, respectively. CI for overweight, generalized obesity, and abdominal obesity was positive, which indicate inequality in favor of low SES groups. Area of residence, family history of obesity, and age were the most contributing factors to the inequality of obesity prevalence observed between the highest and lowest SES groups. ConclusionThis study provides considerable information on the high prevalence of excess weight in families with higher SES at national and provincial levels. These findings can be used for international comparisons and for healthcare policies, improving their programming by considering differences at provincial levels.