London, March 25 (IANS): Air pollution is linked to a higher risk of stroke, particularly in developing countries, finds a new study, while another study links pollution to anxiety.

In a systematic review and meta-analysis, a team of researchers from Edinburgh University looked at the association between short-term air pollution exposure and stroke-related hospital admissions and deaths.

In total, they analysed 103 observational studies that covered 28 countries across the world. The results, published in The BMJ, 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 (1.4 percent per 10 ppb) and stroke-related hospital admissions or death.

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 Aug/m3 increment, respectively.

The first day of air pollution exposure was found to have the strongest association. Low- to middle-income countries experienced the strongest associations compared to high-income countries.

Only 20 percent of analysed studies were from low- to middle-income countries -- mostly mainland China -- despite these countries having the highest burden of stroke.

"These results suggest a need for policy changes to reduce exposure in such highly polluted regions," concluded the authors.

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

Exposure to particulate matter was linked to a higher risk of anxiety. PM2.5 was found to have a significant association with anxiety.