Luchtvervuiling verhoogt kans op hartaanval en beroerte*
Het is inmiddels genoegzaam bekend dat veel bewegen en gezonde voeding goed is tegen
hoge bloeddruk maar Amerikaanse wetenschappers waarschuwen voor een onzichtbaar risico dat de kans op een hartaanval of beroerte duidelijk doet verhogen te weten luchtvervuiling. In een kleine studie met 83 personen blijkt dat 2 uur blootstelling aan lucht zoals die langs een doorgaande stadsweg gevonden wordt meteen leidt tot een duidelijk hogere bloed(onder)druk. Tot 24 uur na de blootstelling zijn verschillende functies van de bloedvaten in heel het lichaam verstoord. Hierdoor ontstaat voor gezonde mensen slechts een kleine kans op hartproblemen doch voor mensen met al hartproblemen doen deze veranderingen de kans op een hartaanval of beroerte flink
toenemen. Bij nadere bestudering bleek niet alleen ozon maar vooral fijnstof in de vervuilde lucht verantwoordelijk te zijn voor de veranderingen in de bloedvaten.
Exposure to air pollution can cause heart attack
It's well known that measures such as exercise, a healthy diet and not smoking can help reduce high blood pressure, but researchers at the University of Michigan Health System have determined the very air we breathe can be an invisible catalyst to heart disease.
Inhaling air pollution over just two hours caused a significant increase in diastolic blood pressure, the lower number on blood pressure readings, according to new U-M research.
The study findings appear in Hypertension, a publication of the American Heart Association.
Nearly one in three Americans suffer from hypertension, a significant health problem that can lead to heart attack, heart failure, stroke, and other life-threatening problems.
"Although this increase in diastolic blood pressure may pose little health risk to healthy people, in people with underlying coronary artery disease this small increase may actually be able to a trigger heart attack or stroke," says Robert D. Brook, M.D., lead author and vascular medicine physician at the U-M Cardiovascular Center.
In the study, researchers hoped to identify which air pollutants are harmful and how the pollutants work to damage the cardiovascular system.
Eighty-three people in Ann Arbor and Toronto were involved in testing and breathed air pollution, concentrated by a mobile air quality research facility, that was similar to what would be found in an urban environment near a roadway.
"We looked at their blood vessels and then their responses before and after breathing high levels of air pollution," explains Robert Bard, M.S., overall research project manager.
Ozone gases, a well-known component of air pollution, were not the biggest culprit. Rather, small microscopic particles about a 10th of the diameter of a human hair caused the rise in blood pressure and impaired blood vessel function, tests showed. The blood pressure increase was rapid and occurred within two hours, while the impairment in blood vessel function occurred later but lasted as long as 24 hours.
It's believed these fine particles deposit deep into the lungs and certain components may gain entrance to the blood stream, or cause an inflammatory response throughout the body. There is also evidence that functions in the body's nervous system are also disrupted.
The research is the latest in the relatively new field of Environmental Cardiology which looks at the association between air pollution and heart disease. Brook says that at the very least the findings support efforts to maintain current ambient air quality standards set by the Environmental Protection Agency.
"It really bolsters and strengthens the importance of maintaining air quality for human health," says Brook.
There are practical ways to avoid exposure to high levels of air pollution, such as avoiding unnecessary travel or commutes and not exercising during rush hour, or near busy roadways, Brook says. In modern society, the burning of fossil fuels is the primary source for air pollution.
"If air pollution levels are forecasted to be high, those with heart disease, diabetes or lung disease should avoid unnecessary outdoor activity," he
says.
Source: http://www.med.umich.edu (Oktober
2009)
