Air pollution ups risk of stroke

Washington: A new study has examined that air pollution is linked to increased risk of anxiety and stroke.

The study conducted at Edinburgh University looked at the association between short term air pollution exposure and stroke related hospital admissions and deaths and in total, they analysed 103 observational studies that covered 28 countries across the world.

Gaseous pollutants included in the analysis were carbon monoxide, sulphur dioxide, nitrogen dioxide and ozone. In addition, particulate matter was included: PM 2.5 (fine particles less than 2.5 um in size) and PM 10 (coarse particles less than 10 um in size).

Results showed an association between carbon monoxide (1.5 percent increased risk per 1 ppm), sulphur dioxide (1.9 percent per 10 ppb) and nitrogen dioxide (1.4percent per 10 ppb) and stroke related hospital admissions or death. The weakest association was found for ozone.

Both PM 2.5 and PM 10 were associated with hospital admissions or deaths due to stroke, by 1.1 percent and 0.3 percent per 10 ug/m3 increment respectively. The first day of air pollution exposure was found to have the strongest association.

A second study from researchers at The Johns Hopkins and Harvard Universities examined the association between particulate air pollution and anxiety.

Anxiety is the most common psychiatric disorder and globally affects around 16 percent of people at some point in life and it was associated with lessened productivity, increased medical care and risk of suicide.

Overall, 71, 271 women, aged between 57 and 85 years, were included in the analysis.

Findings showed that around 15 percent of women experienced high anxiety symptoms and exposure to particulate matter was linked to a higher risk of anxiety. While PM2.5 was found to have a significant association with anxiety, no such link existed with PM 2.5 - 10.

In an accompanying editorial, Michael Brauer from the University of British Columbia, Canada, writes that these studies confirm the urgent need to manage air pollution globally as a cause of ill health and that reducing air pollution could be a cost effective way to reduce the large burden of disease from both stroke and poor mental health.

The study is published in pre-reviewed medical journal The BMJ.