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BOSTON - The fine grit in polluted air boosts the risk of heart disease in older women much more powerfully than scientists realized, a big federally funded study has found, raising questions of whether U.S. environmental standards are strict enough.
The Environmental Protection Agency tightened its daily limit for these tiny specks, known as fine particulates, in September. But it left the average annual limit untouched, allowing a concentration of 15 millionths of a gram for every cubic meter of air.
In this study of 65,893 women, the average exposure was 13 units, with two-thirds of the subjects falling under the national standard. But every increase of 10 units, starting at 0, lifted the risk of fatal cardiovascular disease by about 75 percent. That is several times higher than in a study by the American Cancer Society.
Women more susceptible
It has long been known that particulates can contribute to lung and heart disease, with women perhaps more susceptible than men to heart problems, perhaps because of their smaller blood vessels and other biological differences.
But the degree of risk for older women was less clear. This study started with women who had gone through menopause and were 50 to 79 years old.
Unlike earlier studies, it looked not just at deaths, but also at heart attacks, coronary disease, strokes and clogged arteries. These problems were 24 percent more likely with every 10-unit rise in particles. Almost 3 percent of the women suffered some kind of cardiovascular problem.
The risk varied along with the varying levels of these particles in different neighborhoods within the same city.
In their calculations, the researchers tried to adjust for lower income and other health problems that have been blamed for the higher rates of disease in past studies.
“I think the major contribution is answering the critics of the prior studies,” said the paper’s senior researcher, Dr. Joel Kaufman of the University of Washington. “The effect seems large and important and should be taken seriously.”
The Environmental Protection Agency tightened its daily limit for these tiny specks, known as fine particulates, in September. But it left the average annual limit untouched, allowing a concentration of 15 millionths of a gram for every cubic meter of air.
In this study of 65,893 women, the average exposure was 13 units, with two-thirds of the subjects falling under the national standard. But every increase of 10 units, starting at 0, lifted the risk of fatal cardiovascular disease by about 75 percent. That is several times higher than in a study by the American Cancer Society.
Women more susceptible
It has long been known that particulates can contribute to lung and heart disease, with women perhaps more susceptible than men to heart problems, perhaps because of their smaller blood vessels and other biological differences.
But the degree of risk for older women was less clear. This study started with women who had gone through menopause and were 50 to 79 years old.
Unlike earlier studies, it looked not just at deaths, but also at heart attacks, coronary disease, strokes and clogged arteries. These problems were 24 percent more likely with every 10-unit rise in particles. Almost 3 percent of the women suffered some kind of cardiovascular problem.
The risk varied along with the varying levels of these particles in different neighborhoods within the same city.
In their calculations, the researchers tried to adjust for lower income and other health problems that have been blamed for the higher rates of disease in past studies.
“I think the major contribution is answering the critics of the prior studies,” said the paper’s senior researcher, Dr. Joel Kaufman of the University of Washington. “The effect seems large and important and should be taken seriously.”
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