Disaggregating the longitudinal association between urbanization and body weight in Chinese adults over 1991 – 2015

Urbanization is widely viewed as a major contextual force behind the rising prevalence of overweight and obese people in developing countries. Research in China often conflates between-community difference and within-community change - two separate processes of urbanization that are related to body weight gain. Capitalizing on longitudinal and multilevel data from the 1991 to 2015 China Health and Nutrition Survey, the present study disaggregated the association between change in a community-level urbanicity index and change in individual-level body weight status over time in Chinese adults aged 18–65 years. A positive longitudinal relationship was confirmed between urbanicity and body weight in men, but varied in women by the choice of anthropometric measure. However, for both men and women, such an overall association was largely driven by preexisting between-community differences in the level of urbanization rather than an intrinsic within-community urbanization process. This pattern is robust against two different disaggregation methods. These findings together confirm the inadequate simplicity of the conventional model of community effects on health and nutrition.