PT  - JOURNAL ARTICLE
AU  - Xuemei Qi
AU  - Zhongyan Wang
AU  - Xiaokun Guo
AU  - Xiaoshuang Xia
AU  - Juanjuan Xue
AU  - Guojing Jiang
AU  - Yumeng Gu
AU  - Suqin Han
AU  - Qing Yao
AU  - Ziying Cai
AU  - Xiaojia Wang
AU  - Lin Wang
AU  - Sean X Leng
AU  - Xin Li
TI  - Short-term effects of outdoor air pollution on acute ischaemic stroke occurrence: a case-crossover study in Tianjin, China
AID  - 10.1136/oemed-2019-106301
DP  - 2020 Dec 01
TA  - Occupational and Environmental Medicine
PG  - 862--867
VI  - 77
IP  - 12
4099  - http://oem.bmj.com/content/77/12/862.short
4100  - http://oem.bmj.com/content/77/12/862.full
SO  - Occup Environ Med2020 Dec 01; 77
AB  - Objective Ambient air pollution is associated with ischaemic stroke incidence. However, most of the previous studies used stroke-related hospital admission rather than stroke onset itself. This study aimed to evaluate the relationship between ambient air pollutant exposures and acute ischaemic stroke based on the timing of symptom onset.Methods A time-stratified, case-crossover analysis was performed among 520 patients who had ischaemic stroke admitted to the Second Hospital of Tianjin Medical University (Tianjin, China) between 1 April 2018 and 31 March 2019 (365 days). Daily air pollutant concentrations of particulate matter with aerodynamic diameter 2.5 µm, particulate matter with aerodynamic diameter 10 µm (PM10), sulfur dioxide, nitrogen dioxide, carbon monoxide and ozone were obtained from fixed-site monitoring stations. We used conditional logistic regression to estimate OR and 95% CI corresponding to an increase in IQR of each air pollutant after adjusting for the effects of temperature and relative humidity.Results Overall, a higher risk of ischaemic stroke was found between April and September. During this period PM10 was associated with an increased risk of ischaemic stroke (1-day lag: OR=1.49, 95% CI 1.09 to 2.02; 3-day mean: OR=1.58, 95% CI 1.09 to 2.29) among patients between 34 and 70 years old. Positive associations were also observed between PM10 (1-day lag: OR=1.51, 95% CI 1.10 to 2.07; 3-day mean: OR=1.57, 95% CI 1.08 to 2.29), ozone (1-day lag: OR=1.83, 95% CI 1.16 to 2.87; 3-day mean: OR=1.90, 95% CI 1.06 to 3.42) and ischaemic stroke occurrence among those with hyperlipidaemia.Conclusion Our results suggest that air pollution is associated with a higher risk of ischaemic stroke in younger people or people with hyperlipidemia. These findings still need to be further investigated.