Air Pollution Is A Major Risk Factor For Stroke

Environmental and household pollution is a leading risk factor for stroke worldwide, according to a recent study

An analysis of global stroke data from 1990-2013 has revealed that approximately 90% of stroke events are tied to modifiable risk factors including smoking and low physical activity. Topping the list of risks is exposure to air pollution. 

15 million people a year experience a stroke event; 6 million of which die and 5 million are left with permanent disability. The latest review utilised data from the Global Burden of Disease Study and categorised 17 risk factors in 188 countries associated with stroke burden. 

What are the risk factors? 

29.2% of stroke events were correlated with air pollution, a risk which was particularly pronounced in 'developing' countries. In 2013 alone around 16.9% of global stroke burden was connected to environmental air pollution levels, and rising air pollution levels have notably raised stroke risk since the 1990s. 

“A striking finding of our study is the unexpectedly high proportion of stroke burden attributable to environmental air pollution, especially in developing countries. Smoking, poor diet and low physical activity are some of the major risk factors for stroke worldwide, suggesting that stroke is largely a disease caused by lifestyle risk factors. Controlling these risk factors could prevent about three-quarters of strokes worldwide” 

The FAST test for recognising a stroke event Credit: stroke.org.uk

While air pollution emerged as a strikingly strong risk factor, the array of factors appeared to affect age groups differently. Lack of physical activity played little role in younger age groups, but had a pronounced effect on the over 70s in particular. Similarly household air pollution was more prominent in entral, eastern, and western sub-Saharan Africa and south Asia. 

The top 5 risk factors in the US and UK were high blood pressure, high BMI, a diet low in vegetable and fruit, and smoking. In India and China high blood pressure, a diet low in vegetables and fruit and high sodium were the top factors, with household pollution playing a larger role in India and environmental having a greater effect in China. 

“Taxation has been proven to be the most effective strategy in reducing exposure to smoking and excessive intake of salt, sugar and alcohol. If these risks take a toll on our health, and taxation is the best way to reduce exposure to these risks, it logically follows that governments should introduce such taxation and reinvest the resulting revenue back into the health of the population by funding much needed preventative programmes and research in primary prevention and health. All it takes is recognition of the urgent need to improve primary prevention, and the good will of the governments to act” 

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