Medications commonly prescribed for people with high blood pressure may protect them from the potentially deadly effects of air pollution, according to a new study that examined hundreds of older men.
Numerous studies have shown that people die more often from heart attacks, strokes and other cardiovascular problems on smoggy and sooty days. But Harvard University researchers have found that two types of drugs, calcium channel blockers and beta blockers, apparently can shield the effects of the pollutants.
The scientists reported that calcium channel blockers "had the most profound effect" on preventing air pollution from disrupting heart rates, according to the study published in this week's online journal Environmental Health Perspectives. Widely used for two decades, the medications, such as Procardia and Cardizem, are prescribed for high blood pressure and some cardiac problems. Beta blockers, prescribed for the same conditions, also were protective but less so.
Epidemiologists believe that fine particles of soot, mostly from diesel exhaust and factories, and ozone, the main ingredient of smog, can interfere with the nervous system's control over variations in heart rates. People with low heart rate variability are considered prone to heart attacks.
The team at Harvard's School of Public Health, led by Dr. Sung Kyun Park, examined 497 men -- average age 72 -- from the Boston area, comparing their heart functions to air pollution levels recorded nearby. The scientists reported that on days when ozone and fine particle pollution increased, the men had lower readings for heart rate variability; there was less of an effect on those taking the medications.
Dr. Henry Gong, a USC professor of medicine who specializes in the health effects of air pollutants, said it was plausible that the medications could shield people from all causes of heart rate problems, including air pollution. But scientists would have to compare people taking the drugs who were breathing purified air with those breathing polluted air to offer more substantial evidence, he said.
Because the lungs and heart work together, experts theorize that when tiny particles are inhaled, they inflame the lungs, triggering a neurological response in the heart. The calcium blocker medications, designed to stop calcium from reaching heart cells and allow blood to flow more freely to the heart, also may block that unwanted neurological response.
