Exhaust fumes contain small
particulates
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Breathing in air
pollution from traffic fumes can raise the
risk of potentially deadly blood clots, a US
study says.
Exposure to small particulates - tiny
chemicals caused by burning fossil fuels -
is known to increase the chances of heart
disease and stroke.
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 the
blood more sticky and likely to clot.
The team looked at people living in Italy
- nearly 900 of whom developed DVT.
Blood clots which form in the legs can
travel to the lungs, where they can become
lodged, triggering a potentially fatal
pulmonary embolism.
The risk of DVT is known to be increased
by long periods of immobility. In
particular, passengers on long-haul flights
have been shown to be vulnerable, but so are
people who spend long periods of time
sitting at their office desk without
exercising, or walking around.
Researchers obtained pollution readings
from the areas they lived and found those
exposed to higher levels of small
particulates in the year before diagnosis
were more likely to develop blood clots.
The Archives of Internal Medicine report
said for every 10 microgrammes per square
metre increase in small particulates, the
risk of developing a DVT went up by 70%.
Air quality guidelines generally state
that small particulate concentrations should
not exceed 50 microgrammes.
 
Risk factor
Lead researcher Dr Andrea Baccarelli
said: "Given the magnitude of the effects,
our findings introduce a novel and common
risk factor into the development of DVT.
"And, at the same time, they give further
substance to the call for tighter standards
and continued efforts aimed at reducing the
impact of urban air pollutants on human
health."
Dr Beverley Hunt, medical director of the
DVT charity Lifeblood, said: "We have known
for some time that air pollution has been
associated with increased risk of heart
attack and stroke.
"This study shows for the very first time
that air pollution also increases the risk
of clots in the veins and tells us why.
"It's an exciting finding because air
quality is something we can improve on
through tightening air quality legislation." |