Air Pollution May Speed Up Atherosclerosis

[Guest guest]

[file under environmental contamination]

 

Air Pollution May Speed Up Atherosclerosis

http://www.mercola.com/blog/2004/nov/15/air_pollution_may_speed_up_atheroscleros\

is

 

Air pollution may not only be hazardous to your lungs, it may trigger and

accelerate the narrowing of your carotid arteries, according to a new

study. In fact, researchers found an association between long-term air

pollution exposure and the early stages of atherosclerosis (hardening of

the arteries).

 

Even worse, air pollution may contribute to cardiovascular problems at a

very early stage of the disease, similar to smoking, and enhances

atherosclerosis, which is the underlying disease process of cardiovascular

diseases, one scientist said.

 

Researchers reviewed data from two clinical trials on some 800 people over

39 who live in the metro Los Angeles area, including baseline measurements

of the thickness of the inner lining of the patients' neck arteries

(carotid artery intima-media thickness or CIMT). CIMT is measured by

ultrasound and used to determine the level of subclinical atherosclerosis.

 

Researchers then assigned a PM2.5 particle level -- pollutants emitted from

burning fossil fuels or processing metals with a diameter of no more than

2.5 micrometers -- to the study subjects' home ZIP codes. These pollutants

are tiny enough to be inhaled into the smallest airways.

 

Air pollution causes the body to produce oxidants (unstable molecules) that

cause inflammatory reactions in both the respiratory tract and blood

vessels, triggering artery damage. Some air particles find their way into

the blood or even the brain, according to scientists.

 

The association between air pollution and CIMT was especially strong among

these groups:

 

* People over age 60

* Women (especially those over age 60)

* Those who take cholesterol-lowering medication

 

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Air Pollution May Cause And Speed Up Artery Disease

Source: American Heart Association

2004-11-15

 

NEW ORLEANS, Nov. 7 – Air pollution may trigger and accelerate narrowing of

carotid arteries, according to a study presented at the American Heart

Association's Scientific Sessions 2004.

 

http://www.sciencedaily.com/releases/2004/11/041108013341.htm

 

Researchers found an association between long-term air pollution exposure

and the early stages of atherosclerosis (hardening of the arteries).

 

" We knew that people in more polluted areas die earlier from cardiovascular

disease, but it was not clear how early in the disease process air

pollution contributes. Our study found that air pollution may contribute to

cardiovascular problems at a very early stage of the disease, similar to

smoking, and enhances atherosclerosis, which is the underlying disease

process of cardiovascular diseases, " said study author Nino Kuenzli, M.D.,

Ph.D., associate professor, division of environmental health, Keck School

of Medicine at the University of Southern California in Los Angeles.

 

Researchers reviewed data from two clinical trials on 798 people age 40 and

older who lived in the Los Angeles area. The data included baseline

measurements of the thickness of the inner lining of participants' neck

arteries (carotid artery intima-media thickness or CIMT). CIMT is measured

by ultrasound and used to determine the level of subclinical atherosclerosis.

 

Researchers then assigned a PM2.5 particle level to the study subjects'

home ZIP codes. PM2.5 particles are pollutants with a diameter of 2.5

micrometers or less. They are commonly produced by burning fossil fuels

such as driving cars, and smelting and processing metals. They are tiny

enough to be inhaled into the smallest airways.

 

PM2.5 levels are measured in micrograms per meter cubed (ug/m3). In this

study, readings ranged from 5.2 to 26.9 ug/m3.

 

For every 10 ug/m3 increase of PM2.5, CIMT increased by 5.9 percent. After

adjusting for age, socio-demographic, lifestyle (including active and

passive smoking) and physiological factors, researchers determined that

CIMT rose by 3.9 percent to 4.3 percent for every 10 ug/m3 increase in

PM2.5. The association between air pollution and CIMT was even greater

among people over age 60, women and people taking cholesterol-lowering

medication.

 

Overall, the strongest association was seen in women age 60 or older, with

a 15.7 percent increase in CIMT for every 10 ug/m3 increase of PM2.5.

 

Kuenzli said that the air pollution causes the body to produce oxidants

(unstable molecules) that cause inflammatory reactions in both the

respiratory tract and blood vessels, triggering artery damage. Some air

particles find their way into the blood or even the brain, he said. Other

constituents of air pollution may be neutralized locally, but secondary

reaction products may still cause systemic responses. " The responses may

involve both the autonomic nervous system (which controls breathing and

blood pressure) and inflammation in the blood. Both pathways together can

lead to a state of subclinical chronic inflammation, causing adverse

consequences in the blood vessels where oxidized lipids damage the artery

walls. This can lead to thickening of the artery wall, calcification and

plaques – and ultimately ruptures, " Kuenzli said.

 

" It is interesting that the effects of air pollution were particularly

strong in older women. Also, those with increased cardiovascular risk

profiles appeared to be at higher risk of an association between air

pollution and narrowing of the arteries, " he said.

 

" However, the study is too small and not designed to clarify whether

effects are truly different in men and women, old and young, or whether

part of the differences are caused by uncertainties such as in how exposure

was assessed, " Kuenzli said.

 

" Given that cardiovascular disease is the leading cause of death, and that

large populations are exposed to ambient PM2.5 at the levels observed in

this study, these findings need to be corroborated. The public health

implications could be immense, " he said.

 

Co-authors are Wendy J. Mack, Ph.D.; Howard N. Hodis, M.D.; Michael

Jerrett, Ph.D.; Laurie LaBree, M.S.; Frank Gilliland, M.D., Ph.D.; Duncan

Thomas, Ph.D.; John Peters, M.D., Sc.D.; and doctoral student Bernardo

Beckermann.

 

 

================================================================================\

===

ORIGINAL NEWS RELEASE

http://www.newsisfree.com/iclick/i,60613870,192,f/

 

Meeting Report

11/07/2004

 

Air pollution may cause and speed up artery disease

 

NEW ORLEANS, Nov. 7 – Air pollution may trigger and accelerate narrowing of

carotid arteries, according to a study presented at the American Heart

Association’s Scientific Sessions 2004.

 

Researchers found an association between long-term air pollution exposure

and the early stages of atherosclerosis (hardening of the arteries).

 

“We knew that people in more polluted areas die earlier from cardiovascular

disease, but it was not clear how early in the disease process air

pollution contributes. Our study found that air pollution may contribute

to cardiovascular problems at a very early stage of the disease, similar to

smoking, and enhances atherosclerosis, which is the underlying disease

process of cardiovascular diseases,” said study author Nino Kuenzli, M.D.,

Ph.D., associate professor, division of environmental health, Keck School

of Medicine at the University of Southern California in Los Angeles.

 

Researchers reviewed data from two clinical trials on 798 people age 40 and

older who lived in the Los Angeles area. The data included baseline

measurements of the thickness of the inner lining of participants’ neck

arteries (carotid artery intima-media thickness or CIMT). CIMT is measured

by ultrasound and used to determine the level of subclinical atherosclerosis.

 

Researchers then assigned a PM2.5 particle level to the study subjects’

home ZIP codes. PM2.5 particles are pollutants with a diameter of 2.5

micrometers or less. They are commonly produced by burning fossil fuels

such as driving cars, and smelting and processing metals. They are tiny

enough to be inhaled into the smallest airways.

 

PM2.5 levels are measured in micrograms per meter cubed (ug/m3). In this

study, readings ranged from 5.2 to 26.9 ug/m3.

 

For every 10 ug/m3 increase of PM2.5, CIMT increased by 5.9 percent. After

adjusting for age, socio-demographic, lifestyle (including active and

passive smoking) and physiological factors, researchers determined that

CIMT rose by 3.9 percent to 4.3 percent for every 10 ug/m3 increase in

PM2.5. The association between air pollution and CIMT was even greater

among people over age 60, women and people taking cholesterol-lowering

medication.

 

Overall, the strongest association was seen in women age 60 or older, with

a 15.7 percent increase in CIMT for every 10 ug/m3 increase of PM2.5.

 

Kuenzli said that the air pollution causes the body to produce oxidants

(unstable molecules) that cause inflammatory reactions in both the

respiratory tract and blood vessels, triggering artery damage. Some air

particles find their way into the blood or even the brain, he said. Other

constituents of air pollution may be neutralized locally, but secondary

reaction products may still cause systemic responses.

 

“The responses may involve both the autonomic nervous system (which

controls breathing and blood pressure) and inflammation in the

blood. Both pathways together can lead to a state of subclinical chronic

inflammation, causing adverse consequences in the blood vessels where

oxidized lipids damage the artery walls. This can lead to thickening of

the artery wall, calcification and plaques – and ultimately ruptures,”

Kuenzli said.

 

“It is interesting that the effects of air pollution were particularly

strong in older women. Also, those with increased cardiovascular risk

profiles appeared to be at higher risk of an association between air

pollution and narrowing of the arteries,” he said.

 

“However, the study is too small and not designed to clarify whether

effects are truly different in men and women, old and young, or whether

part of the differences are caused by uncertainties such as in how exposure

was assessed,” Kuenzli said.

 

“Given that cardiovascular disease is the leading cause of death, and that

large populations are exposed to ambient PM2.5 at the levels observed in

this study, these findings need to be corroborated. The public health

implications could be immense,” he said.

 

Co-authors are Wendy J. Mack, Ph.D.; Howard N. Hodis, M.D.; Michael

Jerrett, Ph.D.; Laurie LaBree, M.S.; Frank Gilliland, M.D., Ph.D.; Duncan

Thomas, Ph.D.; John Peters, M.D., Sc.D.; and doctoral student Bernardo

Beckermann.

 

Statements and conclusions of study authors that are published in the

American Heart Association scientific journals are solely those of the

study authors and do not necessarily reflect association policy or

position. The American Heart Association makes no representation or

warranty as to their accuracy or reliability.

 

 

 

NR04 - 1319 (SS04-Mack-Kuenzli)

 

 

 

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