Women In Polluted Areas At Higher Risk Of Cardiovascular

Discussion on health consequences of air particulates

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Women In Polluted Areas At Higher Risk Of Cardiovascular

Postby pm2.5mary » Fri Feb 02, 2007 7:52 pm

Web address: http://www.sciencedaily.com/releases/20 ... 204115.htm

Source: University of Washington
Date: February 1, 2007

Women In Polluted Areas At Higher Risk Of Cardiovascular Disease

Science Daily — Women living in areas with higher levels of air pollution have a greater risk of developing cardiovascular disease and subsequently dying from cardiovascular causes, according to a University of Washington study appearing in the Feb. 1 issue of The New England Journal of Medicine. The study is one of the largest of its kind, involving more than 65,000 Women's Health Initiative Observational Study participants, age 50 to 79, living in 36 cities across the United States.

UW researchers studied women who did not initially have cardiovascular disease, following them for up to nine years to see who went on to have a heart attack, stroke, or coronary bypass surgery, or died from cardiovascular causes. They linked this health information with the average outdoor air pollution levels near each woman's home, and found that higher pollution levels posed a significant hazard -- much higher than previously thought -- for development of cardiovascular disease.

The researchers studied levels of fine particulate matter, which are tiny airborne particles of soot or dust, and can come from a variety of sources, like vehicle exhaust, coal-fired power plants, industrial sources, and wood-burning fireplaces. These particles are less than 2.5 microns in diameter -- about 30 to 40 of them would equal the diameter of a human hair. Particulate matter levels are monitored and regulated by the U.S. Environmental Protection Agency (EPA). They're typically invisible to the human eye once they're in the atmosphere, though they may be visible in dense clouds as they come out of a tailpipe, smokestack or chimney, and are responsible for urban haze.

"These soot particles, which are typically created by fossil-fuel combustion in vehicles and power plants, can contain a complex mix of chemicals," explained Dr. Joel Kaufman, professor of environmental & occupational health sciences, epidemiology, and medicine at the UW, and leader of the study. "The tiny particles -- and the pollutant gases that travel along with them -- cause harmful effects once they are breathed in."

Fine particulate matter is measured in micrograms (or millionths of a gram) per cubic meter; cities in the study had average levels of fine particulate matter ranging from about 4 to nearly 20 micrograms per cubic meter. The researchers found that each 10-unit increase in fine particulate matter level was linked to a 76 percent increase in the risk of death from cardiovascular disease, after taking into account known risk factors such as blood pressure, cholesterol, and smoking. Higher long-term average levels of fine particulate matter also led to a higher overall risk of cardiovascular disease events, including stroke and heart attack.

They also found that local differences in particulate matter levels within a city, as well as exposure differences between cities, translate to a higher or lower risk of cardiovascular disease and related death.

"Our findings show that both what city a woman lived in, and where she lived in that city, affected her exposure level and her disease risk," said Kristin Miller, first author of the study and a doctoral student in epidemiology at the UW.

Previous studies have found apparent links between airborne particulate matter and cardiovascular disease, but this study was the first to look specifically at new cases of cardiovascular disease in previously healthy subjects and local air pollution levels within metropolitan areas. Researchers used data from the multi-site Women's Health Initiative Observational Study, which is funded by the National Heart Lung and Blood Institute of the National Institutes of Health (NIH), and coordinated through a center based at the Fred Hutchinson Cancer Research Center in Seattle. The EPA and the National Institute of Environmental Health Sciences provided funding for the study of the effects of air pollution.

Scientists don't understand exactly how fine particulate matter may be leading to cardiovascular disease, but some believe that the soot particles are accelerating atherosclerosis, or hardening of the arteries, which is the major precursor of heart disease.

"This could be a cellular and biochemical process that starts in the lung and then proceeds from there into the cardiovascular system," Kaufman explained. "Or it could be that these very small particles actually enter the blood stream through vessels in the lung, and then begin affecting blood vessels throughout the body." Kaufman is leading a major new EPA-funded study to uncover these mechanisms -- an air-pollution study based on the NIH's Multi-Ethnic Study of Atherosclerosis, or MESA. The MESA Air Pollution Study tackles two key areas for understanding this problem, Kaufman said: investigating the mechanisms through which particulate matter leads to cardiovascular disease, and identifying the sources of pollution that cause the problem. "Preventing these effects requires reducing the pollution at the source," Kaufman said.

The implications of this connection could be very significant.

"More than one out of three deaths in the United States are due to cardiovascular disease -- it's the leading cause of death," Miller said. "If the annual average concentration of fine particulate air pollution can be reduced, it would potentially translate on a national scale to the prevention or delay of thousands and thousands of heart attacks, strokes, and bypass surgeries, not to mention fewer early deaths."

An editorial from researchers at the Harvard School of Public Health and Brigham and Women's Hospital will accompany the study in the Feb. 1 issue of the journal. In that editorial, the authors suggest public health interventions to address this problem, as well as a tightening of the EPA standards regulating fine particulate matter pollution.

In addition to Kaufman and Miller, the study included researchers from the UW School of Medicine and the School of Public Health and Community Medicine, the Fred Hutchinson Cancer Research Center, and Harborview Medical Center, all in Seattle.

NOTE: To determine the average annual concentration of fine particulate matter for a particular city or county, visit the EPA's Air Trends Web site and look for "PM 2.5 Wtd AM" in the tables provided. The most recent data available from the EPA is from 2005. http://www.epa.gov/airtrends/factbook.html

Note: This story has been adapted from a news release issued by University of Washington.


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"Particulate pollution is the most important contaminant in our air. ...we know that when particle levels go up, people die. " (Joel Schwartz, Ph.D., Harvard School of Public Health, E Magazine, Sept./Oct. 2002)
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Study finds grit in polluted air raises heart risks for wome

Postby pm2.5mary » Fri Feb 02, 2007 8:37 pm

Same study...more coverage.
Study finds grit in polluted air raises heart risks for women
By Jeff Donn, Associated Press | February 1, 2007

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 US environmental standards are strict enough.

The Environmental Protection Agency tightened its daily limit for these 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.

"There was a lot of evidence previously suggesting that the long-term standard should be lower, and this is adding one more study to that evidence," said Douglas Dockery, a pollution specialist at the Harvard School of Public Health.

He wrote an accompanying editorial for the study, which was published in today's New England Journal of Medicine. The University of Washington-based researchers worked from data collected for the Women's Health Initiative, a respected research project that previously showed the heart dangers of hormone supplements.

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 the particles in different neighborhoods within the same city.


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"Particulate pollution is the most important contaminant in our air. ...we know that when particle levels go up, people die. " (Joel Schwartz, Ph.D., Harvard School of Public Health, E Magazine, Sept./Oct. 2002)
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Air Pollution Linked To Heart Disease

Postby pm2.5mary » Fri Feb 02, 2007 8:53 pm

Air Pollution Linked To Heart Disease – Smog Causes Heart Disease Stroke And Death – New Study Shows Particulates More Dangerous
Submitted by Marsha Quinn on February 1, 2007 - 2:15am. Health | Heart and Lung
Air Pollution Linked To Heart Disease – Smog Causes Heart Disease Stroke And Death – New Study Shows Particulates More Dangerous

Dr. Joel Kaufman

Scientists have found a link between air pollution and heart disease, and the results suggest the link is much more profound than previously thought. Although the Environmental Protection Agency (EPA) lowered the daily limit of “fine” particulates in September, some wonder if they went far enough. The EPA did not change the annual limit which allows for 15 millionths of a gram for every cubic meter of air.

The study involved 65,893 women enrolled in the Women's Health Initiative and was publicly funded. Douglas Dockery, a pollution specialist at the Harvard School of Public Health wrote in the editorial "There was a lot of evidence previously suggesting that the long-term standard should be lower, and this is adding one more study to that evidence.”

Women could be more susceptible than men because of smaller blood vessels. According to Associated Press reporter Jeff Donn, unlike earlier studies that looked at just deaths, this research evaluated heart attacks, coronary disease, strokes and clogged arteries. These problems were 24 percent more likely with every 10-unit rise in particles.

The risk can vary depending on the neighborhood of a city. The senior researcher, Dr. Joel Kaufman of the University of Washington said, “I think the major contribution is answering the critics of the prior studies. The effect seems large and important and should be taken seriously."

Donn says the EPA is planning to take another look at its standards for particulate matter. "It's too soon to say how much weight any single study will have, but this study will be considered as part of this continuous process," said EPA spokesman John Millett.

By Marsha Quinn
Best Syndication Health Writer
"Particulate pollution is the most important contaminant in our air. ...we know that when particle levels go up, people die. " (Joel Schwartz, Ph.D., Harvard School of Public Health, E Magazine, Sept./Oct. 2002)
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