In 1995 cardiovascular diseases accounted for nearly 15 million deaths, approximately 30% of deaths worldwide. Smokers are becoming increasingly aware of the links between smoking and heart disease as warnings such as "smoking causes heart disease" are emblazoned across cigarette packaging across the world. The effects of second hand smoke or passive smoking is less clear because it is difficult to measure the exposure of non-smokers to cigarette smoke. Researchers at the University of Athens in Greece have carried out an extensive survey of approximately 2000 non-smoking patients. The patients were volunteers from two different groups, the first contained patients who had attended hospital suffering from a heart attack or acute angina that was not a result of a pre-existing condition. The second control group consisted of patients being treated as outpatients for routine examinations or minor surgical procedures who had no history of cardiovascular problems.
Both groups completed a questionnaire, which asked a variety of questions to identify factors that may put them at risk of developing heart problems. These factors included age, hypertension, high cholesterol, diabetes, a family history of heart disease, physical inactivity, obesity, poor education, depression and low income.
In addition, their exposure to second hand cigarette smoke was gauged by asking two questions: "Are you currently exposed to cigarette smoke to more than 30mins/day?" and "As an adult how many years have you been exposed to second hand smoke?"
The researchers analysed the odds of developing heart disease for non-smokers who were exposed to cigarette smoke whilst excluding the effects of other factors.
The results showed that even people who were exposed to cigarette smoke less than 3 times a week (for more than 30 minutes on each occasion) had a 26% increased risk of developing acute heart disorders. These results led the researchers to conclude that "The only safe way to protect non-smokers from exposure to cigarette smoke is to eliminate this health hazard from public places through legislation"
Indeed they go further to suggest that "the consistency of these findings ... increases the belief that the observed association (between passive smoking and heart disease) may represent cause and effect."
The full text of this research is freely available in the open access journal BMC Public Health: http://www.biomedcentral.com/1471-2458/2/9/
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BMC Public Health