Life-course social disparities in body mass index trajectories across adulthood: cohort study evidence from China Health and Nutrition Survey

Abstract

Background: The social disparities in obesity may originate in early life and adult social class. There are various developmental trajectories of overweight/obesity in adulthood. It is unclear how the intergenerational mobility of socioeconomic status influences adult overweight/obesity in China. Methods: We used longitudinal data from ten waves of the China Health and Nutrition Survey (CHNS) between 1989 and 2015 for our analysis. The group-based trajectory modeling was used to identify BMI trajectories in adulthood. Multinomial logistic regression was adopted to assess the associations between SES and adult BMI trajectories. Results: Among a total of 3,138 participants, three latent clusters, including normal-stable BMI (51.4%), progressive overweight group (39.8%), and progressive obesity group (8.8%), were identified. High father's occupational position, high participants’ occupation position and educational attainment, respectively, were associated with greater obesity risk. Compared to a stable low life course SES trajectory, a stable high life course SES trajectory was associated with a 2.35-fold risk of obesity, and upward and downward social mobility trajectories increased the risk for overweight/obesity. Individuals in the highest relative to the lowest life course cumulative socioeconomic score group had around twice risk of obesity. Conclusions: The results emphasize the role of the high SES in early life and life-course SES accumulation, in the obesity intervention in China. Funding:All the work was supported by the National Natural Science Foundation of China (Grant Nos. 72174167, 81602928) and Natural Science Foundation of Shaanxi (2021JM-031).