Association between air pollution and cardiovascular mortality in China: a systematic review and meta-analysis

// Lei Zhao 1, 2, * , Heng-Rui Liang 3, * , Feng-Ying Chen 1 , Zi Chen 5, 6 , Wei-Jie Guan 4 and Jian-Hua Li 1 1 Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Affiliated Cancer Hospital and Institute of Guangzhou Medical University, Guangzhou, 511436, China 2 The Sixth Affiliated Hospital, Guangzhou Medical University, Guangzhou, 511436, China 3 Nan Shan School, Guangzhou Medical University, Guangzhou, 511436, China 4 State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Disease, The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, 510120, China 5 Huashan Hospital, Fudan University, Shanghai, 200040, China 6 QuintilesIMS Asia Medical Oncology, Shanghai, 200032, China * These authors contributed equally to this work Correspondence to: Jian-Hua Li, email: lijianh@hotmail.com Wei-Jie Guan, email: battery203@163.com Zi Chen, email: drchenzi2@163.com Keywords: air pollution, cardiovascular, mortality, China, meta-analysis Received: June 13, 2017 Accepted: July 26, 2017 Published: August 09, 2017 ABSTRACT Air pollutant levels in many Chinese cities remained significantly higher than the upper limits stated in World Health Organization guidelines. In light of limited evidence in China, we conducted a meta-analysis summarizing the association between acute exposure of air pollution and cardiovascular mortality. We searched PubMed, and CNKI databases etc. for literature published in English or Chinese up to January 2017. Outcomes were pooled and compared using random-effects model. Excess risks (ERs) per 10 μg/m 3 increase in PM 2.5 , PM 10 , NO 2 , SO 2 and O 3 were evaluated. Subgroup analysis was conducted according to lag patterns (lags 0, 1, 2, 0–1, 0–2 days), gender (male vs. female), temperature (cool vs. warm) and age (< 65 vs. ≥ 65). Study bias was detected using Begg’s and Egger’s test. Of 299 articles identified, 30 met inclusion criteria. Each 10 μg/m 3 increase in the concentration was associated with a higher incidence of cardiovascular mortality for PM 2.5 (0.68%, 95% CI: 0.39–0.97%), PM 10 (0.39%, 95% CI: 0.26–0.53%), NO 2 (1.12%, 95% CI: 0.76–1.48%), SO 2 (0.75%, 95% CI: 0.42–1.09%), and O 3 (0.62%, 95% CI: 0.33–0.92%), respectively. Air pollution conferred greater adverse impacts on cardiovascular mortality for longer duration of exposures. Strongest associations were seen for lag 0–1 day of exposure among all pollutants. Female, lower temperature, and age > 65 years were associated with greater risks of cardiovascular mortality for all pollutants. Higher concentrations of air pollutants correlated with a greater short-term increase in cardiovascular mortality. Further high-quality studies in China are urgently warranted to determine the susceptible population, which would offer reference for policy-making to minimize adverse health effects.