Breathing in air pollution from traffic fumes can raise the
risk of potentially deadly blood clots, a US study says.
small particulates - tiny chemicals caused by burning fossil
fuels - is known to increase the chances of heart disease and
But the Harvard School of Public Health found it
also affected development of deep vein thrombosis - blood
clots in the legs - in a study of 2,000 people.
Researchers said the pollution made theblood more sticky and
likely to clot.
The team looked at people living in
Italy- nearly 900 of whom developed DVT.
which form in the legs cantravel to the lungs, where they
can becomelodged, triggering a potentially fatalpulmonary
The risk of DVT is known to be increasedby
long periods of immobility. Inparticular, passengers on
long-haul flightshave been shown to be vulnerable, but so
arepeople who spend long periods of timesitting at their
office desk withoutexercising, or walking around.
Researchers obtained pollution readingsfrom the areas they
lived and found thoseexposed to higher levels of
smallparticulates in the year before diagnosiswere more
likely to develop blood clots.
The Archives of
Internal Medicine reportsaid for every 10 microgrammes per
squaremetre increase in small particulates, therisk of
developing a DVT went up by 70%.
guidelines generally statethat small particulate
concentrations shouldnot exceed 50 microgrammes.
Lead researcher Dr Andrea
Baccarellisaid: "Given the magnitude of the effects,our
findings introduce a novel and commonrisk factor into the
development of DVT.
"And, at the same time, they give
furthersubstance to the call for tighter standardsand
continued efforts aimed at reducing theimpact of urban air
pollutants on humanhealth."
Dr Beverley Hunt, medical
director of theDVT charity Lifeblood, said: "We have
knownfor some time that air pollution has beenassociated
with increased risk of heartattack and stroke.
study shows for the very first timethat air pollution also
increases the riskof clots in the veins and tells us why.
"It's an exciting finding because airquality is something we
can improve onthrough tightening air quality legislation."