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Meta-Analysis
. 2023 Apr 15:255:114814.
doi: 10.1016/j.ecoenv.2023.114814. Epub 2023 Mar 23.

Air pollution and stroke hospitalization in the Beibu Gulf Region of China: A case-crossover analysis

Meijun Li  1 , Randall C Edgell  2 , Jing Wei  3 , Haopeng Li  1 , Zhengmin Min Qian  4 , Jin Feng  1 , Fei Tian  1 , Xiaojie Wang  1 , Qinghua Xin  5 , Miao Cai  6 , Hualiang Lin  7
Affiliations
Meta-Analysis

Air pollution and stroke hospitalization in the Beibu Gulf Region of China: A case-crossover analysis

Meijun Li et al. Ecotoxicol Environ Saf. .

Abstract

Background: The relationship between air pollution and stroke has been extensively studied, however, the evidence regarding the association between air pollution and hospitalization due to stroke and its subtypes in coastal areas of China is limited.

Objective: To estimate the associations between air pollution and hospitalizations of stroke and its subtypes in the Beibu Gulf Region of China.

Methods: We conducted a time-stratified case-crossover study in 15 cities in Beibu Gulf Region in China from 2013 to 2016. Exposures to PM1, PM2.5, PM10, SO2, NO2, O3, and CO on the case and control days were assessed at residential addresses using bilinear interpolation. Conditional logistic regressions were constructed to estimate city-specific associations adjusting for meteorological factors and public holidays. Meta-analysis was further conducted to pool all city-level estimates.

Results: There were 271,394 case days and 922,305 control days. The odds ratios (ORs) for stroke hospitalizations associated with each interquartile range (IQR) increase in 2-day averages of SO2 (IQR: 10.8 µg/m3), NO2 (IQR: 11.2 µg/m3), and PM10 (IQR: 37 µg/m3) were 1.047 (95 % CI [confidence interval]: 1.015-1.080), 1.040 (95 % CI: 1.027-1.053), and 1.018 (95 % CI: 1.004-1.033), respectively. The associations with hospitalizations of ischemic stroke were significant for all seven pollutants, while the association with hemorrhagic stroke was significant only for CO. The associations of SO2, NO2, and O3 with stroke hospitalization were significantly stronger in the cool season.

Conclusions: Short-term increase in SO2, NO2, and PM10 might be important triggers of stroke hospitalization. All seven air pollutants were associated with ischemic stroke hospitalization, while only CO was associated with hemorrhagic stroke hospitalization. These results should be considered in public health policy.

Keywords: Air pollution; Beibu Gulf Region; Case-crossover study; China; Hospitalization; Stroke.

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Conflict of interest statement

Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Figures

ga1
Graphical abstract
Fig. 1
Fig. 1
The geographic distribution of stroke hospitalizations in Beibu Gulf Region, China, 2013–2016.
Fig. 2
Fig. 2
Combined odds ratios (ORs) and 95 % confidence intervals (CIs) in hospital admissions for stroke associated with an interquartile range (IQR) increase in short-term (2-day average) exposure to PM1(16.6 µg/m3), PM2.5 (27 µg/m3), PM10(37 µg/m3), SO2 (10.8 µg/m3), NO2 (11.2 µg/m3), O3 (38.6 µg/m3), and CO (0.32 mg/m3) in the Beibu Gulf Region, China.
Fig. 3
Fig. 3
Exposure-response curves on the associations of PM1 (µg/m3), PM2.5 (µg/m3), PM10 (µg/m3), SO2 (µg/m3), NO2 (µg/m3), O3 (µg/m3), CO (mg/m3) with hospital admissions for stroke. The pollutants were trimmed at 0.1-th percentiles in order to prevent excessively large confidence intervals and abnormally nonlinear patterns resulting from small sample sizes. The solid lines with shaded bands represent the odds ratio of hospital admissions and their corresponding 95 % confidence intervals, respectively.
See this image and copyright information in PMC

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