Times of India , Wednesday, May 14, 2008

Correspondent : Staff Reporter

WASHINGTON: It's not just your lungs that are at risk from air pollution - a new study has linked this modern menace to the formation of blood clots as well. The study, by Harvard researchers, found that every 10 microgram per square metre increase in particulate matter upped the risk of clot development by a whopping 70 per cent. Exposure to fine particles of solid and liquid chemicals, released by burning fossil fuels, has already been linked to increased risk of heart disease and stroke. Andrea Baccarelli of Harvard analysed exposure to particulate matter among 870 patients diagnosed with such clots (deep vein thrombosis) between 1995 and 2005. These patients, along with 1,210 controls who were free of the condition, were assigned to one of nine geographic regions based on where they lived at the time of the study. The researchers then used the average concentration of particulate matter for each area to estimate the level of exposure over the year before diagnosis (for cases) or examination (for controls). Individuals with deep vein thrombosis tended to have a higher exposure to particulate air pollution than controls - and for every increase in particulate matter of 10 micrograms per square metre the previous year, the risk of deep vein thrombosis increased 70 per cent. The association between particle exposure and blood clots was stronger in men than in women, and disappeared among women taking oral contraceptives or hormone therapy. "Such hormone therapies are independent risk factors for deep vein thrombosis, which is also confirmed in this study by the higher prevalence of oral contraceptive and hormone use in the cases compared with the controls," Baccarelli said. According to experts, particulate matter ranks as the 13th leading cause of global mortality, causing an estimated 800,000 deaths annually. Findings of the study have appeared in the latest issue of the Archives of Internal Medicine.

SOURCE : Times of India, Wednesday, 14 May 2008