Pollution causes blood clots

More bad news for those living in polluted areas. Particles of carbon, nitrates and metals from cars and factories may also increase the risk of deep vein thrombosis - blood clots in the legs.

A study at the Harvard School of Public Health in Boston found that for every 10 microgram increase in 'particulate matter' per square metre, there was a 70% increase in the risk of DVT - sometimes also called "economy class syndrome" because travellers who sit still for too long in a cramped plane often suffer from it. On top of that, the blood of those with higher levels of exposure to particulate matter was quicker to clot when tested at a clinic, they reported in the Archives of Internal Medicine.

Air pollution has already been linked to lung diseases and later to heart disease and stroke. The findings Ð the result of a study of 2000 people in Italy between 1995 and 2005 - introduce a new and common risk for DVT. The researchers called for Ôtighter standards and continued efforts aimed at reducing the impact of urban air pollutants on human health.'

In a commentary, Dr. Robert Brook of the of the University of Michigan in Ann Arbor said if the findings are proven by additional research it may turn out that 'the actual totality of the health burden posed by air pollution, already known to be tremendous, may be even greater than ever anticipated.'