Trends in urban/rural inequalities in cardiovascular risk biomarkers among Chinese adolescents in two decades, 1991–2011

Abstract

Introduction Urban living affects children's nutrition and growth, which determine their survival, cognitive development and lifelong health. Despite well-documented rural-urban inequalities in child health in China, there are few attempts to examine how these relationships have changed during the process of China's urbanisation. This study aims to examine urban/rural inequalities in cardiovascular risk biomarkers among Chinese adolescents in two decades from 1991 to 2011 during the process of China's rapid urbanisation. Methods Data were drawn from a nationwide longitudinal dataset of the China Health and Nutrition Survey (CHNS) (sweeps 1991, 1993, 1997, 2000, 2004, 2006, 2009 and 2011). Children aged between 12 and 17 years (boys: n = 6,055; girl: n = 5,528) were included. A dynamic urbanisation index was created for each community (village or neighbourhood) based on community-level data that can reveal the heterogeneity within and across places and capture dimensions of social, economic and physical characteristics of urban living over time and space. Multilevel modeling analyses (level 1: occasions; level 2: individuals; level 3: households; level 4: communities) were performed on outcomes of cardiovascular risk biomarkers including anthropometric measures and blood pressure. Cardiovascular risk biomarkers increase during 1991 to 2011. Results After adjustment for individual- and household-level confounders, urbanisation tends to have an independent and positive impact on BMI and waist circumference for boys but not for girls. We found significant and positive interaction effect between urbanisation index and survey years for waist circumference for girls: time trends become greater when areas become more urbanized. For blood pressure, when areas become more urbanized the trends for boys become less pronounced. Conclusions Chinese adolescents are experiencing an upward trend of cardiovascular risk in last two decades. Its rapid urbanisation appears to further increase the risk, especially for boys, which may contribute to the development of cardiovascular disease in adulthood. Given China's urbanisation is strongly influenced by the state, there is a possibility for policy intervention to reduce inequality during the process of China's planned urbanisation.