Geographical Disparity and Associated Factors of COPD Prevalence in China: A Spatial Analysis of National Cross-Sectional Study

• Type of Material: Article
• Authors: Ning Wang, Queensland University of Technology; Shu Cong, Chinese Center for Disease Control and Prevention; Jing Fan, Chinese Center for Disease Control and Prevention; Heling Bao, Chinese Center for Disease Control and Prevention; Baohua Wang, Chinese Center for Disease Control and Prevention; Ting Yang, China Japan Friendship Hospital; Yajing Feng, Chinese Center for Disease Control and Prevention; Yang Liu, Emory University; Linhong Wang, Chinese Center for Disease Control and Prevention; Chen Wang, China Japan Friendship Hospital; Wenbiao Hu, Queensland University of Technology; Liwen Fang, Chinese Center for Disease Control and Prevention
• Language: English
• Date: 2020-01-01
• Publisher: Dove Medical Press Ltd.
• Publication Version: Final Published Version
• Copyright Statement: © 2020 Wang et. al.
• License: Creative Commons Attribution-Noncommercial 3.0 Unported
• Final Published Version (URL): http://dx.doi.org/10.2147/COPD.S234042
• Title of Journal or Parent Work: International Journal of Chronic Obstructive Pulmonary Disease
• Volume: 15
• Start Page: 367
• End Page: 377
• Grant/Funding Information: N Wang was supported by the Queensland University of Technology Postgraduate Research Award and Queensland University of Technology Higher Degree Research International Tuition Fee Sponsorship.; The study was funded by the Ministry of Science and Technology of People’s Republic of China (National Key R&D Program of China: 2016YFC1303905, 2016YFC1303900), The Chinese Central Government (Key Project of Public Health Program, Grant No. 2014814).; W Hu is supported by Australian Research Council future fellowship (FT140101216).
• Keywords: Risk; Respiratory System; COPD; Air pollution; Life Sciences & Biomedicine; Mortality; Classification; Science & Technology; classification and regression tree; Health; spatial clusters; kriging; Obstructive pulmonary disease
• Research Categories: Engineering, Biomedical; Environmental Sciences; Health Sciences, Public Health

Abstract

Purpose: COPD prevalence has rapidly increased in China, but the geographical disparities in COPD prevalence remain largely unknown. This study aimed to assess city-level disparities in COPD prevalence and identify the relative importance of COPD related risk factors in mainland China. Patients and Methods: A nationwide cross-sectional study of COPD recruited 66,752 adults across the mainland China between 2014 and 2015. Patients with COPD were ascertained by a post-bronchodilator pulmonary function test. We estimated the city-specific prevalence of COPD by spatial kriging interpolation method. We detected spatial clusters with a significantly higher prevalence of COPD by spatial scan statistics. We determined the relative importance of COPD associated risk factors by a nonparametric and nonlinear classification and regression tree (CART) model. Results: The three spatial clusters with the highest prevalence of COPD were located in parts of Sichuan, Gansu, and Shaanxi, etc. (relative risks (RRs)) ranging from 1.55 (95% CI 1.55–1.56) to 1.33 (95% CI 1.33–1.33)). CART showed that advanced age (≥60 years) was the most important factor associated with COPD in the overall population, followed by smoking. We estimated that there were about 28.5 million potentially avoidable cases of COPD among people aged 40 or older if they never smoked. PM2.5 was an important associated risk factor for COPD in the north, northeast, and southwest of China. After adjusting for age and smoking, the spatial cluster with the highest prevalence shifted to most of Sichuan, Gansu, Qinghai, and Ningxia, etc. (RR 1.65 (95% CI 1.63–1.67)). Conclusion: The spatial clusters of COPD at the city level and regionally varied important risk factors for COPD would help develop tailored interventions for COPD in China. After adjusting for the main risk factors, the spatial clusters of COPD shifted, indicating that there would be other potential risk factors for the remaining clusters which call for further studies.