Air pollution has become a major contributor to stroke for the first time, with unclean air now blamed for nearly one third of the years of healthy life lost to the condition worldwide.
In an unprecedented survey of global risk factors for stroke, air pollution in the form of fine particulate matter ranked seventh in terms of its impact on healthy lifespan, while household air pollution from burning solid fuels ranked eighth.
Valery Feigin, director of the National Institute for Stroke and Applied Neurosciences at Auckland University of Technology, said that while he expected air pollution to emerge as a threat, the extent of the problem had taken researchers by surprise.
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“We did not expect the effect would be of this magnitude, or increasing so much over the last two decades,” he said. “Our study is the first to demonstrate a large and increasingly hazardous effect of air pollution on stroke burden worldwide.”
The result is particularly striking because the analysis is likely to have underestimated the effects of air pollution on stroke, as the impact of burning fossil fuels was not fully accounted for. Emissions from fossil fuels are more harmful to the cardiovascular system than the fine particulate matter the team analysed, Feigin said.
Scientists in the field said the “alarming” finding, published in the journal Lancet Neurology, showed that harm caused by air pollution to the lungs, heart and brain had been underestimated.
About 15 million people a year suffer a stroke worldwide. Nearly six million die, and five million are left with permanent disabilities, such as loss of sight and speech, paralysis and confusion.