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Air pollution leading risk factor for stroke: study

Friday, Jun 10, 2016,16:52 IST By Metrovaartha A A A

Melbourne | Air pollution has emerged as a leading risk factor for stroke worldwide, associated with about a third of the global burden of the disease, a new study of data from 188 countries, including India, has found.

The findings, from an analysis of global trends of risk factors for stroke between 1990-2013, also show that over 90 per cent of the global burden of stroke is linked to modifiable risk factors, most of which (74 per cent) are behavioural risk factors such as smoking, poor diet and low physical activity, researchers from Auckland University of Technology in New Zealand said.

According to them, control of these risk factors could prevent about three-quarters of all strokes. The study is the first to analyse the global risk factors for stroke in such detail, especially in relation to stroke burden on global, regional and national levels.

Researchers used data from the Global Burden of Disease Study to estimate the disease burden of stroke associated with 17 risk factors in 188 countries. They estimated the population-attributable fraction (PAF) of stroke-related disability-adjusted life years (DALYs) such as the estimated proportion of disease burden in a population that would be avoided if exposure to a risk factor were eliminated.

Every year, approximately 15 million people worldwide suffer a stroke – of these, nearly six million die and five million are left with permanent disability. Disability may include loss of vision and/or speech, paralysis and confusion.

Globally, the ten leading risk factors for stroke were high blood pressure, diet low in fruit, high body mass index (BMI), diet high in sodium, smoking, diet low in vegetables, environmental air pollution, household pollution from solid fuels, diet low in whole grains, and high blood sugar.

About a third (29.2 per cent) of global disability associated with stroke is linked to air pollution (including environmental air pollution and household air pollution). This is especially high in developing countries (33.7 per cent vs 10.2 per cent in developed countries), researchers said.

In 2013, 16.9 per cent of the global stroke burden was attributed to environmental air pollution (as measured by ambient particle matter (PM) pollution of aerodynamic diameter smaller than 2.5 micrometre) – almost as much as that from smoking (20.7 per cent), they said.

From 1990 to 2013, stroke burden associated with environmental air pollution (PM25) has increased by over 33 per cent, researchers said. The study also provides information on the contribution of all 17 risk factors for stroke for 188 countries.

For example, the top five risk factors for stroke in India were high blood pressure, diet low in fruit, household air pollution, diet low in vegetables, diet high in sodium.