Association of Socioeconomic Status and Overweight/Obesity in Rural-to-Urban Migrants: Different Effects by Age at Arrival

摘要

This study aims to investigate the association between socioeconomic status and overweight/obesity in rural-to-urban Yi migrants in China, and to explore whether the association varied by the age at arriving urban areas. The cross-sectional population-based data from the Yi Migrants Study in 2015 was used, which included 1,181 Yi migrants aged 20–80 years. Socioeconomic status was evaluated by education level, personal annual income, and a composited variable (socioeconomic status index, SESI). Measured weight and height were used to calculate BMI and to define overweight/obesity (BMI ≥ 24 kg/m 2 ). The results suggested that the association of income and SESI with overweight/obesity was not significant when age at arrival (two groups, 20 and ≥20 years) was considered as a covariate. In the stratification analysis, reversed association was observed in the two groups of age at arrival. In migrants of 20 years of age at arrival, higher level of education and SESI were related to decreased risk of overweight/obesity. In contrary, in those of ≥20 years at arrival, higher socioeconomic status level was found to be related to increased risk. Our findings suggest that the effect of socioeconomic status on overweight/obesity was modified by the age at arrival in Yi migrants. Especially, the association between socioeconomic status and overweight/obesity was negative when migration before 20 years of age, and transfer to positive after 20 years.