Traffic-related air pollution tied to stroke death

08:54, April 07, 2010      

Email | Print | Subscribe | Comments | Forum 

Traffic-related air pollution may be linked to a higher death rate among people who initially survived strokes, hint study findings from the United Kingdom.

Of 3320 men and women who lived in a specific south London region and had a first stroke between 1995 and 2005, Dr. Ravi Maheswaran, at the University of Sheffield, and colleagues found more deaths among those exposed to higher estimated traffic-related pollution over more than a decade.

Maheswaran's team used 2002 estimates of two common traffic pollutants -- nitrogen dioxide and small, inhalable particles called particulate matter -- linked to breathing difficulties and other health problems.

Their report, in the journal Stroke, shows risk of dying increased 28 percent when nitrogen dioxide levels rose by just 10 micrograms per 3 square meters of air. A likewise increase in particulate matter increased death risk by 52 percent, they report.

All of the areas were typical of London. The low-pollution areas typically did not have major roads running through them. The higher pollution areas had levels of nitrogen dioxide that the U.S. Environmental Protection Agency consider the U.S. average.

The researchers report more deaths in the higher polluted neighborhoods - 975 of 1659 patients, or about 59 percent, in high nitrogen dioxide neighborhoods and 967 of 1658 patients, or about 58 percent, in high particulate matter areas.

That compared to 881 of 1661 patients, or about 53 percent, in an area less polluted by high nitrogen dioxide, and 889 of 1662 patients, or about 53 percent, in an area less polluted by high particulate matter.

Risk for death remained higher with greater air pollution exposure after the investigators took into account a number of other factors associated with stroke death including age, gender, ethnicity, smoking and alcohol use, high blood pressure, heart disease, and diabetes.

If future investigations show air pollution causes death among stroke patients, a 10 microgram reduction in nitrogen dioxide exposure - about a 10 percent decrease from the average in the highest pollution areas -- "would be associated with a 22 percent decrease in mortality after stroke," Maheswaran and colleagues write.

It's unclear why stroke patients may be more vulnerable to the long-term effects of air pollution, notes Dr. Jiu-Chiuan Chen, at the University of Southern California Keck School of Medicine, in Los Angeles, in a related editorial. However, some studies have linked living near high levels of traffic pollution to clogged arteries.

Source: China Daily/Agencies


  • Do you have anything to say?


Special Coverage
  • Premier Wen Jiabao visits Hungary, Britain, Germany
  • From drought to floods
Major headlines
Editor's Pick
  • The photo, taken on Sept. 26, shows the SWAT team ready for the joint exercise. (Xinhua/Wangkai)
  • Two metro trains in Shanghai collided Tuesday afternoon, and an identified number of passengers were injured in the accident, the Shanghai-based reported. Equipment failures were believed to have caused the crash on the Line 10 subway, Xinhua quoted local subway operator as saying.
  • An employee at a gold store in Yiwu, located in east China's Zhejiang province, shows gold jewelry on Monday.(Xinhua/Zhang Jiancheng)
  • Tourists ride camels near China's largest desert lake Hongjiannao in Yulin, north China's Shaanx Province, Sept. 24, 2011. Hongjiannao is shrinking as a result of climate change and human activities, and may vanish in a few decades. Its lake area, which measured more than 6,700 hectares in 1996, has shrunk to 4,180 hectares. Its water level is declining by 20-30 centimeters annually and its water PH value has risen to 9.0-9.42 from 7.4-7.8. (Xinhua/Liu Yu)
  • Actors perform royal dance at the Gyeongbok Palace in Seoul, Sept. 27, 2011. A ceremony commemorating the 38th South Korea Sightseeing Day was held in Gyeongbok Palace on Tuesday. (Xinhua/He Lulu)
  • Actress Huang Jieqiong performs at the opening ceremony of the Second Ecological and Cultural Tourism Festival in Enshi Tujia and Miao Autonomous Prefecture, central China's Hubei Province, Sept. 26, 2011. (Xinhua/Hao Tongqian)
Hot Forum Discussion