Urban-rural disparities in cardiovascular disease risks among middle-aged and older Chinese: two decades of urbanisation

China has been undergoing dramatic socio-economic and demographic changes in the last few decades. The rapid growth of the ageing population will pose tremendous challenges to its public health and social welfare system. This study aims to examine how urbanisation has impacted cardiovascular disease (CVD) risks among middle-aged and older Chinese in two decades, from 1991 to 2011. Data were drawn from a nationwide longitudinal data-set of the China Health and Nutrition Survey (CHNS) (sweeps 1991, 1993, 1997, 2000, 2004, 2006, 2009 and 2011). Participants aged > 45 years old 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. Multi-level modelling analyses (level 1: occasions; level 2: individuals; level 3: households; level 4: communities) were performed on outcomes of CVD risks such as body mass index, waist circumference, and systolic and diastolic blood pressure. The results show upward trends in all CVD risks for both genders over 20 years of urbanisation after adjustment for socio-economic and demographic confounders. Urbanisation in China is associated with absolute increases in CVD risks over time among its middle-aged and older people, despite its contribution to relative reduction of the rural-urban gap over time. This is particularly true for women from the least urbanised areas. It is relevant to inform policy-making processes to target the most vulnerable groups of older people in China during its rapid urbanisation process. There is a possibility for policy intervention to reduce inequality during the process of China's planned urbanisation.