Association and potential mediators between socioeconomic status and childhood overweight/obesity

The associations between socioeconomic status and childhood overweight/obesity are inconsistent, and potential underlying factors are unclear. In China, Hukou status is an important attribute of individual's socioeconomic circumstances, but previously received less consideration as a socioeconomic indicator. This study aimed to investigate the association between comprehensive socioeconomic status and childhood overweight/obesity. Using data from Wuhan Maternal and Child Health Management Information System (2009-2018, N = 209,500), clustering analysis was used to create comprehensive socioeconomic groups with indicator components such as parental education level, occupation, and maternal Hukou. The associations between the determined socioeconomic status and childhood overweight/obesity at age 1 and 2 were examined by log-binomial model. Parallel and serial mediation analyses were performed to test the indirect effects of potential mediators, including maternal pre-pregnancy body mass index, gestational weight gain, and infant birth weight, in the association between socioeconomic status and childhood overweight/obesity. Four clusters, defined as low, low-medium, medium-high, and high socioeconomic groups, were identified through clustering analysis. Hukou, among five socioeconomic components, contributed the most to the development of childhood overweight/obesity. Children in the low-medium socioeconomic group have a greater risk of overweight/obesity than the low socioeconomic group. Indirect effects of maternal pre-pregnancy body mass index, gestational weight gain, and infant birth weight were identified for the association. In conclusion, socioeconomic status may impact childhood obesity through maternal pre-pregnancy body mass index, gestational weight gain, and infant birth weight. Hukou should be considered in the evaluation of socioeconomic status in China.