14 May 2008

Pollution ups blood clot risk

Air pollution may cause blood clots in the legs, the same condition air travellers call 'economy class syndrome' caused by immobility during flight.

Air pollution that is heavy in small particles may cause blood clots in the legs, the same condition air travellers call 'economy class syndrome' caused by immobility during flight, researchers claimed.

Dr Andrea Baccarelli of the Harvard School of Public Health in Boston and colleagues said they found the link after looking at 870 people in Italy who had developed deep vein thrombosis between 1995 and 2005.

When compared with 1 210 others living in the same region who did not have the problem, they found that for every increase in particulate matter of 10 micrograms per square meter the previous year, the risk of deep vein thrombosis increased by 70 percent.

On top of that, the blood of those with higher levels of exposure to particulate matter, when tested at a clinic, was quicker to clot, they reported in the Archives of Internal Medicine.

Lung disease not only problem caused
Air pollution from automobiles and industry can contain tiny particles of carbon, nitrates, metals and other materials that have been linked over the years to a variety of health problems.

While lung diseases were an initial concern, later research has indicated it may cause heart disease and stroke, possibly because it increases the rate at which blood can coagulate, Baccarelli and colleagues said.

Until now particulate pollution had not been linked to blood clots in the veins. The mechanism that causes problems for some air travellers is related not to the blood itself, but to impaired circulation when sitting in one place without exercise for long periods of time.

The findings introduce a new and common risk for deep vein thrombosis, the researchers said and "give further substance to the call for tighter 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." – (Reuters Health)

Air pollution in South Africa
“This is yet more evidence from a recent trend in international research indicating that air pollution contributes to cardiovascular disease as well as lung disease," says Olivia Rose-Innes, Health24's Environmental Expert.

"These findings are highly relevant to South Africa: some of our urban areas – South Durban is perhaps the most notorious example – rank among the most polluted in the world. The poorest city-dwellers have the worst exposure, because they’re the ones who end up living in the most polluted areas, like the edges of highways – but all urbanites are affected.”

According to Siziwe Khanyile from Groundwork, a Durban-based environmental justice organization the air pollution hot spots, as recognized by government, include: the Vaal Triangle, south Durban, the Highveld (especially Secunda, Witbank and Standardton) and certain regions in Cape Town.

"In South Africa, air pollution is responsible for a lot of respiratory disease, particularly asthma… depending on the industry, air pollution also causes cancer, leukemia, nausea, headache, eye irritation, and more," Khanyile points out.

The most common chemicals found in South African air pollution are oxides of sulphur and nitrogen, volatile organic compounds, particulate matter and in some regions even mercury, according to Khanyile.

“We’re starting to get stricter with air pollution legislation and monitoring, but we've got a lot of work to do to get our air pollution to ‘acceptable’ levels (though some would argue there is no acceptable level!). To quote the Department of Environmental Affairs and Tourism: ‘Existing ambient air quality guidelines do not protect people’s health and well-being. …South Africa’s limits for particulates… are more lenient than internationally accepted international health thresholds’,” says Rose-Innes.

(Health24/Reuters Health)

Read more:
Air pollution may lower IQ
Air pollution hurts sperm


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