Pollution linked to strokes
2003-11-24 12:21
Taipei - City air pollution can greatly increase a person's chances of having a stroke, according to Taiwanese researchers.
Scientists in Taiwan found a clear link between increasing levels of two common pollutants and hospital stroke admissions, especially on warm days.
The researchers collected data on 23 179 stroke patients between 1997 and 2000 in Kaohsiung, Taiwan's largest city and an industrial centre.
They found that as exposure to sooty particles called PM10s and nitrogen dioxide went up, so did the number of stroke admissions.
Pollution levels on admission dates were compared with those one week before and one week after patients were admitted.
From this it was possible to calculate the effect of pollution on stroke risk.
"For every PM10 change of 66.33 micrograms per cubic metre the risk of being admitted to hospital with a stroke caused by a burst blood vessel in the brain rose 54%."
A similar risk increase was produced by every extra 7.08 parts per billion of nitrogen dioxide.
"The effect was most noticeable on warm days when the temperature rose above 20C, or 68F."
Professor Chun-Yuh Yang, from Kaohsiung Medical University, who led the research, said: "This study provides new evidence that higher levels of ambient pollutants increase the risk of hospital admissions for stroke, especially on warm days."
The findings were published in the American Heart Association journal, Stroke.
Previous studies have shown associations between air pollution and daily death rates for lung and heart disease. But there has been conflicting evidence regarding stroke.
Many experts suspect that air pollution may affect blood volume and the resistance of blood vessels and heart structures.
Professor Yang said further work could lead to drugs that might protect people from short-term exposure to pollutants - for instance, during rush-hour traffic.
"In hot weather, we recommend that people avoid pollution, stay inside and use an air conditioner if needed," he said." - Sapa-DPA
- SAPA