Israelis who have suffered a heart attack are far more at risk of a repeat attack if they live in an area with high levels of air pollution, new research has found.
The study, by Tel Aviv University and the Technion - Israel Institute of Technology in Haifa, found that cardiac patients living in polluted areas were 43 percent more likely to have another heart attack than those who lived in areas with cleaner air. It also found they were 43 percent more likely to suffer congestive heart failure, and 46 percent more likely to have a stroke.
"Given that heart patients are already at least three times more likely than the general public to have another heart problem, they must be especially careful about air pollution," said chief researcher Dr. Yariv Gerber, of the School of Public Health in Tel Aviv University's medical department.
The researchers followed 1,120 heart patients aged up to 65 who had suffered heart attacks between 1992 and 1993 and were treated at eight hospitals in the central region. The research protocol neutralized the impact of age, sex and socioeconomic status. The patients were monitored through 2005.
Air quality was measured at 21 monitoring stations near the communities where the patients lived. The level of pollution exposure was determined by the number of pollutant particles up to 2.5 microns in size - small enough to penetrate a person's airways - as well as by exposure to nitric oxide. Heavy vehicles and factories are primarily responsible for this type of pollution, making those who live in the center of the country particularly vulnerable.
A follow-up study conducted in 2011 found that the cardiac patients who were exposed to air pollution were 39 percent more likely to have died during the 19 years following their heart attack than those not so exposed.
"Arteriosclerosis is today considered to be a disease linked to inflammation, and air-polluting particles that irritate the cells lead to inflammation, in the same way smoking cigarettes does," said Gerber, who noted that the findings supported the results of similar studies carried out in the United States and Europe.
The researchers were surprised by one result, however. In contrast to findings in the rest of the world, which link living in high-pollution areas to lower socioeconomic status, the dynamic in Israel's central region means the opposite is true - that wealthier people were more likely to be living in areas with high levels of air pollution.
While the link between smoking and illness has been studied for decades, research on the relationship between air pollution and illness is relatively new. The first report of a link between air pollution and heart problems appeared in the New England Journal of Medicine in 1993.
In 2010, scientists in the north of Israel found a link between air pollution in the Haifa Bay area and the rate of lung cancer among men who lived there. This new study provides further evidence of the cumulative damage that pollution can cause.