Medical News Today News Article

Pollution Linked To Deep Vein Thrombosis And Blood = Clots

13=20 May 2008

New=20 research on people living in Italy, suggests that long term = exposure=20 to air pollution is linked to an increased risk of deep vein = thrombosis and blood clots in the legs or thighs, adding to = previous=20 research findings linking particulate air pollution and = increased=20 risk of death from cardiovascular diseases.

The study = is=20 published in the May 12th issue of the Archives of = Internal=20 Medicine and is the work of Dr Andrea Baccarelli, from = the=20 Harvard School of Public Health in Boston, US, and = colleagues from=20 other research centres in Italy and the US.

Air = pollution=20 comprises small particles and fine droplets of chemical = matter=20 produced from burning fossil fuels and other sources. = Previous=20 research has linked increasing concentrations of particulate = air=20 pollution with increased risk of heart disease and stroke, = and=20 scientists have suggested this could be due to the particles = causing=20 blood coagulation and arterial thrombosis, wrote the authors = in=20 their background information.

Baccarelli and = colleagues=20 obtained data on 870 deep vein thrombosis (DVT) patients = from the=20 Lombardy region of Italy who had been diagnosed between 1995 = and=20 2005 and matched them to 1,210 controls who did not have = DVT.=20

Then they assessed the patients' exposure to = particulate air=20 pollution in the year before their diagnosis, and for = controls, the=20 year before their examination. They used measured mean = levels of=20 particles smaller than 10 micrometers in diameter (PM10) = obtained=20 from pollution monitors located in 53 different sites within = the=20 nine geographic areas where the patients and controls=20 lived.

The results showed that:=20

Individuals with DVT tended to have a higher exposure = to PM10=20 air pollution particles than controls.
There was a significant link between higher mean PM10 = particle=20 levels and shortened prothrombin time (PT, a measure of = blood=20 clotting tendency) in DVT cases .
After adjusting for other environmental and health = factors,=20 for every increase in PM10 concentration of 10 micrograms = per=20 cubic metre in the year before diagnosis, the risk of DVT=20 increased by 70 per cent.
The link between PM10 level and DVT risk was stronger = in men=20 than women, and went away among women on oral = contraceptives or on=20 hormone therapy.

On the effect of hormone = therapy and=20 contraceptives, the authors wrote that "Such hormone = therapies are=20 independent risk factors for deep vein thrombosis, which is = also=20 confirmed in this study by the higher prevalence of oral=20 contraceptive and hormone use in the cases compared with the = controls."

They concluded that:

"Long-term = exposure to=20 particulate air pollution is associated with altered = coagulation=20 function and DVT risk. Other risk factors for DVT may = modulate the=20 effect of particulate air pollution."

They said their = findings "introduce a novel and common risk factor into the=20 pathogenesis of deep vein thrombosis," and add weight to the = case=20 for tighter controls to reduce urban air = pollution.

In an=20 accompanying editorial titled "Blood Clot Risk Could = Increase=20 Estimates of Death Toll from Pollution", Dr Robert D Brook = of the=20 University of Michigan, Ann Arbor, wrote that air=20 pollution:

"Has become so omnipresent over the past = century=20 as to be commonly perceived as a normal natural entity - the = lazy,=20 hazy days of summer."

But he adds that, "While we = have=20 learned to live within this haze without a second thought, = air=20 pollution is neither natural nor benign."

Although at = any one=20 point in time the absolute risk to one person's = cardiovascular=20 health posed by particulate air pollution is minute, it is = the=20 constant, ubiquitous nature of the exposure that places it = at 13th=20 place among the world's biggest killers, accounting for = around=20 800,000 deaths a year, wrote Brook, who added that this = study sheds=20 light on a new risk posed by air pollution.

"If = future=20 studies corroborate their findings and address some of the=20 limitations, it may be proven that the actual totality of = the health=20 burden posed by air pollution, already known to be = tremendous, may=20 be even greater than ever anticipated", he=20 concludes.

"Exposure to Particulate Air = Pollution and=20 Risk of Deep Vein Thrombosis."
Andrea Baccarelli; = Ida=20 Martinelli; Antonella Zanobetti; Paolo Grillo; Li-Fang Hou; = Pier A.=20 Bertazzi; Pier Mannuccio Mannucci; Joel Schwartz
Arch = Intern=20 Med. 2008;168(9):920-927.
Vol. 168 No. 9, May 12,=20 2008

Click here for=20 Article.

Sources: Journal abstract and = JAMA=20 press release.

Written by: Catharine Paddock, = PhD=20
Copyright: Medical News Today
Not to be reproduced = without=20 permission of Medical News Today

Article URL:=20 http://www.medicalnewstoday.com/articles/107178.php

Main News Category: Water - Air Quality / = Agriculture

Also Appears In: Blood / Hematology,=20 Vascular,

=20

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