Passive smoking may up heart disease risk

Exposure to secondhand tobacco smoke, as a child or in adulthood, can increase the risk of developing heart disease, a new research has warned.
In the research presented at the American College of Cardiology's 62nd Annual Scientific Session, scientists found that 26 per cent of people exposed to varying levels of secondhand smoke had signs of coronary artery calcification (CAC), compared to 18.5 per cent in the general population.
The new data also showed 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, 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.
"This research provides additional evidence that secondhand smoke is harmful and may be even more dangerous than we previously thought," said study author Harvey Hecht.
"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," Hecht said.

After adjusting for other cardiovascular risk factors, people classified as having low, moderate or high secondhand smoke exposure were 50, 60 and 90 per cent 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.
"Tobacco smoke can damage the coronary arteries of nonsmokers through many different ways, which can lead to plaque formation and then to heart attacks, so this lends more [credence] to enforcing smoking bans," Hecht said in a statement.
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 programme from 2005-2012.