Geographical profiles of cardiovascular risk and the risk factors in China: data from a nationwide population-based screening project
Authors: Wu C.Q , Li X , Lu J.P , Chen B.W , Li Y.C , Yang Y , Li J , Hu S.S 
Published: November 2020

Abstract

Background
In China, an abundance of cardiovascular risk factors has contributed to the increasing prevalence of cardiovascular diseases (CVD), which caused almost 4 million deaths per year. However, comprehensive evidence on the geographical profiles of cardiovascular disease risk in China is lacking, as findings in prior studies have been limited to relatively small sample sizes, had incomplete regional coverage, or focused on a narrow risk factor spectrum.

Purpose
To compare the population CVD risk among different regions across China, and to describe the geographical distributions of CVD risk factors and their clusters throughout the nation.

Methods
In a nationwide population-based screening project covering 252 counties of China, standardized measurements were conducted to collect information on 12 major CVD risk factors. Individuals of high CVD risk were identified as those with previous CVD, or with a predicted 10-year risk of CVD greater than 10% according to the WHO risk prediction charts. We applied factor analysis to generate “clusters” that characterized the clustering of these risk factors, then explored their relationship with the local ambient temperature and per capital GDP.

Results
Among 983476 participants included, 9.2% were of high CVD risk, with a range of 1.6% to 23.6% across counties. Among the seven regions in China, the rate was relatively high in the Northeast (11.8%) and North China (10.4%), while low in the South China (7.2%) and Northwest (7.8%). We identified 6 clusters underlying CVD risk factors, including Obesity factor, Blood pressure factor, Staple food factor, Non-staple food factor, Smoking and alcohol factor, and Metabolic and physical activity factor (Figure). We found high risk regions were facing different leading challenges, like obesity and blood pressure for the North China, while unhealthy non-staple food for the Northeast. The South China, as the region with the lowest CVD risk, still had the highest prevalence of unhealthy staple food. Lower annual average ambient temperature was associated with higher risk in Blood pressure factor, Obesity factor and Non-staple food factor, but lower risk in Staple food factor and Metabolic and physical activity factor (p&lt;0.001 for all), consistently between rural and urban. Higher per capital GDP was associated with lower risk in Non-staple food factor in urban and higher risk in Metabolic and physical activity factor in rural (p&lt;0.05 for both). The correlation between per capital GDP and Smoking and alcohol factor differed significantly between in rural and urban regions (p=0.042).

Conclusions
The geographical profile of CVD risk in China is complex - population risk levels varied substantially across regions, which were contributed by different risk factors. China needs geographically targeted intervention strategies considering environmental and socio-economic factors to control CVD risk and reduce the burden related to CVD.
Geographical disparity of risk clusters

Funding Acknowledgement
Type of funding source: Public grant(s) – National budget only. Main funding source(s): The National Key Research and Development Program from the Ministry of Science and Technology of China; the CAMS Innovation Fund for Medical Science