Air pollution and stroke Introduction

Introduction

Outdoor air pollution is an important risk factor for cardiovascular disease throughout the world, with particulate air pollution alone responsible for over three million deaths each year.1 2 Increases in concentrations of daily air pollution are associated with acute myocardial infarction3 and admission to hospital or death from heart failure.4 These associations could be mediated through

 direct and indirect effects of exposure to air pollutants on vascular tone, endothelial function, thrombosis, and myocardial ischaemia.5 6 7 8

Stroke accounts for five million deaths each year and is a major cause of disability.9 The incidence of stroke is increasing, particularly in low and middle income countries, where two thirds of all strokes occur.10 The global burden of stroke related disability is therefore high and continues to rise. This has been primarily attributed to an ageing population in high income countries and the accumulation of risk factors for stroke, such as smoking, hypertension, and obesity, in low and middle income countries.11 12 The impact of environmental factors on morbidity and mortality from stroke, however, might be important and is less certain.13 14 15 Given similarities in the pathophysiology of acute coronary syndrome and ischaemic stroke, it is plausible that air pollution is also an important and modifiable risk factor.3 4

To provide global policy makers with the best estimates of the effect of short term exposure to air pollution on risk of stroke, we systematically reviewed studies examining the association between air pollution and admission to hospital for stroke or mortality from stroke

Ref

 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