[Association analysis between urbanization and non-communicable diseases and health-related behavior]

To explore the association between different urbanization levels and non-communicable diseases (NCDs) in China and provide suggestions on designing relevant health policies in the urbanization process.

We obtained health-related data from China Health and Retirement Longitudinal Study (CHARLS) 2011. This study used multistage sampling in design stage and covered 150 districts/counties, representative at the levels of the country. Geo-information system (GIS) method was used to get district areas data, and in combination with the Sixth National Census population data, we computed the population density which was regarded as the proxy variable of urbanization level in every city. The Logistic model was used to explore the effect of urbanization level on hypertension, diabetes, smoking, drinking, overweight and obesity.

Compared with other cities in China, Shanghai and Shenzhen, with the population density of more than 3 000 people per km(2), were the cities with highest urbanization level. From the map of urbanization distribution across China, it was found that the urbanization levels of the northwestern districts were lower than those of the southeastern and coastal districts. The hypertension rate increased with the development of urbanization but there was no statistical significance. The proportion of patients with diabetes went up first and then saw a decrease trend in the process of urbanization. Drinking rate, overweight rate and obesity rate had similar trends, falling to their lowest point when urbanization level equaled 737,1 186 and 1 353 people per km(2) respectively and then experienced upward trends. By contrast, smoking rate declined first and then went up (the turning point was 1 029 people per km(2)).

Different urbanization levels have different effects on NCDs, health-related behavior, overweight and obesity. Low urbanization level may create negative impact on health while high level can pose positive effect and increase people's health condition possibly due to the improvement of health care accessibility and the quality of living environment. Policy-makers should specially focus on different residents'health problems in different periods of urbanization, such as the impact of environmental pollution, health resources' allocation and accessibility of health services. It is necessary to reduce or avoid the negative effect of urbanization on NCDs during the local development process to face the NCDs' threat.