Aetiology of stroke and exposure to air pollution

 Aetiology of stroke and 

exposure to air polution

While our analysis showed consistent associations for ischaemic stroke and air pollution, the association for haemorrhagic stroke was more variable with larger imprecision. Our results were similar to those from a

 smaller meta-analysis that showed identical patterns with type of stroke and exposure to PM_2.5 and PM₁₀.⁴¹ While haemorrhagic and ischaemic stroke share similar 

risk factors and have a similar clinical presentation, they are different clinical entities.⁴⁵ Heterogeneity in the association between air pollution and stroke subtype might be caused by many factors. Firstly, the mechanisms linking exposure to air pollution and haemorrhagic stroke might differ for

 ischaemic stroke. Secondly, there were fewer estimates for haemorrhagic stroke, reflecting the lower incidence of this subtype, and therefore wider confidence intervals for these estimates. Finally, misclassification of stroke subtype

 in those studies from countries with limited availability of medical imaging might have contributed to some of the observed heterogeneity.^42 46Ref

 BMJ. 2015 Mar 24;350:h1295. doi: 10.1136/bmj.h1295

Short term exposure to air pollution and stroke: systematic review and meta-analysis

Anoop S V Shah 1,✉, Kuan Ken Lee 1, David A McAllister 2, Amanda Hunter 1, Harish Nair 2, William Whiteley 3, Jeremy P Langrish 1, David E Newby 1, Nicholas L Mills