Air Pollution - Cancer Risk Documented

NEW YORK Mar 05, 2002 (Reuters Health) - Breathing polluted air over the long term can increase a person"s risk of dying from lung cancer or heart and lung disease, according to the results of a new study.

Specifically, exposure to high levels of particulate air pollution--tiny particles that can be inhaled deep into the lungs--and sulfur oxide-related pollution were linked to a higher risk of death from these illnesses, as well as death from any cause. Both types of pollution are produced by combustion, such as burning of gas by automobile engines and fuel burning at power plants.

High day-to-day levels of particulate air pollution have been linked to increased risk of death and illness, but the effect of long-term exposure to such pollution has been less clear. No one knows exactly why pollution is toxic to humans, though many experts suspect that pollutants cause inflammation in the lungs or prompt the body to release chemicals that can affect heart function.

To investigate, lead author Dr. C. Arden Pope III of Brigham Young University in Provo, Utah and colleagues evaluated data from a long-term study of 1.2 million people. Data for about 500,000 of these individuals was linked to information on air pollution, vital status and cause of death through 1998.

Pope"s team found that as levels of fine particulates and sulfur oxide-related pollution in the environment rose, so did the death rate from lung cancer and cardiopulmonary diseases, which include heart attack, stroke, asthma, pneumonia and chronic obstructive pulmonary diseases like emphysema and bronchitis.

The death rate from any cause also rose with pollution levels, the authors report in the March 6th issue of The Journal of the American Medical Association.

Specifically, every time the level of particulate matter smaller than 10 micrometers in diameter increased by 10 micrograms per cubic meter, there was approximately a 4%, 6% and 8% increased risk of death from all causes, cardiopulmonary disease, and lung cancer, respectively.

"The findings of this study provide the strongest evidence to date that long-term exposure to fine particulate air pollution common to many metropolitan areas is an important risk factor for cardiopulmonary mortality," the authors write.

"In addition, the large (study group) and extended follow-up have provided an unprecedented opportunity to evaluate associations between air pollution and lung cancer mortality," they add.

Although the potential effects of other factors cannot be excluded with certainty, the associations between fine particulate air pollution and cardiopulmonary and lung cancer deaths remained even after controlling for cigarette smoking, obesity, diet, occupation and other factors that can increase the risk of death from these disorders, Pope and colleagues conclude.

SOURCE:

• The Journal of the American Medical Association 2002;287