哪怕一天的空气污染都能增加中风风险

Air pollution — even for just one day — significantly increases the risk of stroke, a large review of studies has found.

一项大型研究综述发现，空气污染可显著增加中风的风险，即使只是短短一天也依然如此。

Researchers pooled data from 103 studies involving 6.2 million stroke hospitalizations and deaths in 28 countries.

研究人员汇总了103项研究的数据，共计涉及28个国家中的620万例因中风住院和死亡病例。

The analysis, published online in BMJ, found that all types of pollution except ozone were associated with increased risk for stroke, and the higher the level of pollution, the more strokes there were.

这项在线发表于《英国医学杂志》(BMJ)上的分析发现，除臭氧外，所有类型的污染物均与中风风险增加相关，且污染物水平越高，中风病例越多。

Daily increases in pollution from nitrogen dioxide, sulfur dioxide, carbon monoxide and particulate matter were associated with corresponding increases in strokes and hospital admissions. The strongest associations were apparent on the day of exposure, but increases in particulate matter had longer-lasting effects.

二氧化氮、二氧化硫、一氧化碳和颗粒物污染的日增加量与中风和入院的相应增加相关。暴露当天的相关性最强，不过，颗粒物的增加可造成较为持久的影响。

The exact reason for the effect is unclear, but studies have shown that air pollution can constrict blood vessels, increase blood pressure and increase the risk for blood clots. Other research has tied air pollution to a higher risk of heart attacks, stroke and other ills.

这种影响的确切原因尚不清楚，但研究表明，空气污染可引起血管收缩、血压升高，并会增加血栓风险。另有一项研究发现，空气污染与心肌梗死、中风和其他疾病的风险较高相关。

The lead author, Dr. Anoop Shah, a lecturer in cardiology at the University of Edinburgh, said that there was little an individual could do when air pollution spikes. “If you’re elderly or have co-morbid conditions, you should stay inside,” he said. But policies leading to cleaner air would have the greatest effect, he said. “It’s a question of getting cities and countries to change.”

研究的主要作者，爱丁堡大学(University of Edinburgh)的心脏病学讲师亚努皮·沙阿(Anoop Shah)博士说，当空气污染激增时，单个人所能做的非常有限。“如果你是老人或患有并发症，你应该呆在家里。”但可令空气更清洁的政策将产生巨大的效果，他说。“会让城市和国家发生改变。”