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Air pollution can cause lung cancer and seems to worsen heart failure, researchers reported in two studies released Tuesday.
Both show the more pollution, the more disease. One study looked at lung cancer cases across Europe; the other looked at hospitalization for heart failure in several countries, including the United States.
Dr. Ole Raaschou-Nielsen of the Danish Cancer Society Research Center said they couldn’t find a “safe” level of air pollution. The more pollution, the higher the risk, even at legally accepted limits. “The association between particulate matter air pollution and the risk for lung cancer persisted also at concentrations below the existing European Union air quality limit values,” they wrote.
“At this stage, we might have to add air pollution, even at current concentrations, to the list of causes of lung cancer and recognize that air pollution has large effects on public health,” Takashi Yorifuji of the Okayama University Graduate School of Environmental and Life Science in Japan and Saori Kashima of Hiroshima University wrote in comments on the study, published in the Lancet medical journal.
The European team looked at data from 17 different studies involving more than 300,000 people in nine European countries. Over 13 years, 2,095 people developed lung cancer.
They took into account whether people smoked, what they ate and their occupations. Many of the studies directly measured air pollution. “We also collected information on two indicators of traffic at the residence: traffic intensity (vehicles per day) on the nearest street and total traffic load (vehicle-km driven per day) on all major roads within 100 meters (about 100 yards),” the researchers wrote.
A person’s risk of developing lung cancer rose 18 percent for every extra five micrograms of soot per cubic meter of air, they found. While people who smoke may also live in more polluted areas, the large scope of the studies showed that even so, pollution can raise even a non-smoker’s risk of cancer.
The second study looked at 12 countries, including the United States. Nicholas Mills of the University of Edinburgh in Britain and colleagues combined data from 35 studies that assessed carbon monoxide, sulfur dioxide, nitrogen dioxide, and ozone pollution, as well as particulate matter (often simply called soot).
They compared this to rates of being hospitalized for heart failure, a chronic condition in which the heart loses its ability to pump blood effectively. It often grows larger as it struggles, and patients develop fluid buildup around the lungs and limbs and have trouble breathing and walking. About half of people with heart failure die withing five years, according to the American Heart Association.
But patients can also cope with daily living. Mills found one of the things that can throw a heart failure patients into the hospital, or kill them, is breathing polluted air.
An increase of just 1 part per million of carbon monoxide, a clear odorless gas, raised the risk by 3.5 percent; an increase of 10 micrograms per cubic meter of particulate matter raised the risk 2 percent. The biggest risk was on the day the patient actually breathed in the polluted air. The only pollutant that didn’t affect this risk was ozone, they reported in the Lancet.
“While the role of air pollution is well recognized as a risk factor for heart attacks, it has been less clear whether exposure increases the risk of adverse events in patients with other cardiovascular conditions like heart failure,” Mills said in a statement. “Since the entire population is exposed to air pollution, even modest reductions in air pollution could have major cardiovascular health benefits and substantial healthcare cost savings. ”