Butland B K, Atkinson R W, Crichton S, Barratt B, Beevers S, Spiridou A, Hoang U, Kelly F J, Wolfe C D
Population Health Research Institute and MRC-PHE Centre for Environment and Health, St George's, University of London, London, UK.
Division of Health and Social Care Research, Department of Primary Care and Public Health Sciences, King's College London, London, UK.
J Epidemiol Community Health. 2017 Jul;71(7):707-712. doi: 10.1136/jech-2016-208025. Epub 2017 Apr 13.
Few European studies investigating associations between short-term exposure to air pollution and incident stroke have considered stroke subtypes. Using information from the South London Stroke Register for 2005-2012, we investigated associations between daily concentrations of gaseous and particulate air pollutants and incident stroke subtypes in an ethnically diverse area of London, UK.
Modelled daily pollutant concentrations based on a combination of measurements and dispersion modelling were linked at postcode level to incident stroke events stratified by haemorrhagic and ischaemic subtypes. The data were analysed using a time-stratified case-cross-over approach. Conditional logistic regression models included natural cubic splines for daily mean temperature and daily mean relative humidity, a binary term for public holidays and a sine-cosine annual cycle. Of primary interest were same day mean concentrations of particulate matter <2.5 and <10 µm in diameter (PM, PM), ozone (O), nitrogen dioxide (NO) and NO+nitrogen oxide (NO).
Our analysis was based on 1758 incident strokes (1311 were ischaemic and 256 were haemorrhagic). We found no evidence of an association between all stroke or ischaemic stroke and same day exposure to PM, PM, O, NO or NO. For haemorrhagic stroke, we found a negative association with PM suggestive of a 14.6% (95% CI 0.7% to 26.5%) fall in risk per 10 µg/m increase in pollutant.
Using data from the South London Stroke Register, we found no evidence of a positive association between outdoor air pollution and incident stroke or its subtypes. These results, though in contrast to recent meta-analyses, are not inconsistent with the mixed findings of other UK studies.
很少有欧洲研究在调查短期接触空气污染与中风发病之间的关联时考虑到中风亚型。利用2005年至2012年南伦敦中风登记处的信息，我们在英国伦敦一个种族多样化的地区，调查了气态和颗粒状空气污染物的每日浓度与中风亚型发病之间的关联。
基于测量和扩散模型相结合得出的每日污染物浓度模型，在邮政编码层面与按出血性和缺血性亚型分层的中风发病事件相关联。数据采用时间分层病例交叉法进行分析。条件逻辑回归模型包括每日平均温度和每日平均相对湿度的自然三次样条、公共假日的二元项以及正弦余弦年度周期。主要关注的是直径<2.5和<10微米的颗粒物（PM₂.₅、PM₁₀）、臭氧（O₃）、二氧化氮（NO₂）以及一氧化氮（NO）和氮氧化物（NOₓ）的当日平均浓度。
我们的分析基于1758例中风发病病例（1311例为缺血性中风，256例为出血性中风）。我们没有发现所有中风或缺血性中风与当日接触PM₂.₅、PM₁₀、O₃、NO₂或NOₓ之间存在关联的证据。对于出血性中风，我们发现与PM₂.₅呈负相关，表明污染物每增加10微克/立方米，风险下降14.6%（95%可信区间为0.7%至26.5%）。
利用南伦敦中风登记处的数据，我们没有发现室外空气污染与中风发病或其亚型之间存在正相关的证据。这些结果虽然与最近的荟萃分析结果相反，但与英国其他研究的混合结果并不矛盾。
