More links between air pollution and stroke risk

Chengdu, China, 2006

This isn't the first posting here about the link between air pollution and stroke risk.

Of course, air pollution generates many, many other problems. I remember visiting London several years ago and, when blowing my nose, found a tissue full of dirt. In visiting Chengdu, China, later, the city was covered with smog.

I ran in both cities, but couldn't help but notice the affect on my breathing.

Here's one more piece of evidence that air pollution is linked to increased stroke risk:

Air pollution and strokes

This isn't the first blog posting about the potential link between air pollution and strokes, but  ran across yet another article about research on air pollution - including indoor smoking - and how air pollution, heart disease and stroke:

Pollution can come from traffic, factories, power generation, wildfires or even cooking with a wood stove. One of the most common indoor sources is smoking — a danger to the person lighting up and to those nearby.

 “There are a wide variety of things in the air. Some are natural, some are manmade,” said Russell Luepker, M.D., a cardiologist and the Mayo professor in the School of Health at the University of Minnesota. “We are all exposed, to a certain degree.”

Acute short-term effects of air pollution tend to strike people who are elderly or already struggling with heart disease, said Dr. Luepker, who is also an epidemiologist.

For instance, someone with atherosclerosis, or build up of fatty deposits on the inner lining of the arteries, experiences immediate trouble when pollutants play a role in causing plaque in a blood vessel to rupture, triggering a heart attack.

“This kind of pushes them over the cliff,” Dr. Luepker said.

More links between stroke risk, air pollution

Researchers have found more links between stroke risk and air pollution:

After reviewing the medical records of more than 1,700 stroke patients in the Boston area over 10 years, the researchers found a 34 percent increase in the risk of ischemic strokes on days with moderate air quality compared with days when the air was rated good by the U.S. Environmental Protection Agency. Ischemic strokes occur when a clot blocks blood flow to part of the brain.

On days with moderate air quality, levels of fine particulate matter is higher but within allowable limits.

“This is a significant study because we have documentation that the risk of stroke can be elevated when the air quality is still within the guidelines set by the current EPA regulations,” said Dr. Murray A. Mittleman, an author of the study who teaches at Harvard Medical School and works in the CardioVascular Institute at Beth Israel Deaconess. “This implies that the current regulations can be strengthened further to prevent these catastrophic health events.”

Another reason to clear the air

A British study found a connection between pollution and stroke death, as Reuters news service:

Of 3,320 men and women who lived in a specific south London region and had a first stroke between 1995 and 2005, Dr. Ravi Maheswaran, at the University of Sheffield, and colleagues found more deaths among those exposed to higher estimated traffic-related pollution over more than a decade.

Maheswaran's team used 2002 estimates of two common traffic pollutants -- nitrogen dioxide and small, inhalable particles called particulate matter -- linked to breathing difficulties and other health problems.

Their report, in the journal Stroke, shows risk of dying increased 28 percent when nitrogen dioxide levels rose by just 10 micrograms per 3 square meters of air. A likewise increase in particulate matter increased death risk by 52 percent, they report.

Air pollution may pose stroke risk

Food for thought, from a University of Michigan study, about stroke risk and the air you breathe.

A link about how air pollution may pose stroke risk, from the university's Web site. The item reports:

Short-term exposure to low levels of particulate air pollution may increase the risk of stroke or mini-stroke, according to findings that suggest current exposure standards could be insufficient to protect the public.

The vast majority of the public is exposed to ambient air pollution at the levels observed in this community or greater every day, suggesting a potentially large public health impact,' said Lynda Lisabeth, lead author and assistant professor in the University of Michigan School of Public Health.