Washington: Exposure to secondhand tobacco smoke may be more dangerous than previously thought, a new research has warned.
The more you are exposed to secondhand smoke-whether it was during your childhood or as an adult, at work or at home-the more likely you are to develop early signs of heart disease, the research said.
Researchers found that 26 percent of people exposed to varying levels of secondhand smoke had signs of coronary artery calcification (CAC), compared to 18.5 percent in the general population.
The new data also revealed that people who report higher levels of secondhand tobacco smoke exposure also have the greatest evidence of coronary artery calcification, a build-up of calcium in the artery walls as seen on a low-dose computed tomography scan.
While previous studies have shown a marked increase in cardiac events related to secondhand tobacco smoke, the researchers said this study is the first to demonstrate a clear dose-response relationship between secondhand smoke exposure and the earliest detectable signs of heart disease.
"We actually found the risk of secondhand smoke exposure to be an equivalent or stronger risk factor [for CAC] than other well-established ones such as high cholesterol, hypertension and diabetes. Passive exposure to smoke seems to independently predict both the likelihood and extent of CAC," said Harvey Hecht, MD, associate director of cardiac imaging and professor of medicine at Mount Sinai Medical Center and study author.
After adjusting for other cardiovascular risk factors, people classified as having low, moderate or high secondhand smoke exposure were 50, 60 and 90 percent more likely to have evidence of coronary artery calcification than those who reported minimal exposure.
The apparent health effects of secondhand smoke on CAC remained regardless of whether the exposure was during childhood or adulthood.
Dr. Hecht said these results further underscore the need for enforceable public smoking bans and other measures to reduce passive inhalation of cigarette smoke.
This study included 3,098 healthy people between 40 and 80 years old who had never smoked (defined as having smoked fewer than 100 cigarettes in their lifetime) and who were already enrolled in the Flight Attendant Medical Research Institute (FAMRI)-International Early Lung Cancer Action Program CT screening program from 2005-2012.
Compared to those who had minimal exposure to secondhand smoke, people with higher levels of exposure tended to be older, were more often women and more likely to have diabetes, high cholesterol and high blood pressure.
Although his team did not use the standard Agatston score to assess CAC, Dr. Hecht said this study further validates the utility of low-dose non-gated CT scans to measure the amount of plaque in the coronary arteries in nonsmokers exposed to secondhand tobacco smoke.
The study results were presented at the American College of Cardiology`s 62nd Annual Scientific Session.