A study published in The British Medical Journal finds that exposure to secondhand smoke is even more dangerous than previously thought and increases the risk of heart disease among non-smokers by as much as 60 percent.
This study provides the most compelling evidence yet that secondhand smoke causes heart disease. It is the first study to show a direct physical link between secondhand smoke exposure and an increased risk of heart disease. This study underscores the need for states and communities across the country to enact comprehensive clean indoor air laws that require all workplaces and public places to be smoke-free.
The evidence is irrefutable that secondhand smoke isn't just annoying; it is a scientifically proven cause of serious health problems, including heart disease, lung cancer and chronic lung ailments such as bronchitis and asthma. As the evidence grows of the health harms from secondhand smoke, it is absolutely unacceptable for anyone to be exposed to these hazards in the workplace. Elected officials must protect everyone's right to breathe clean air.
The new study, conducted over 20 years by researchers at St. George's Hospital Medical School in London, is particularly important because it measured exposure to secondhand smoke from all sources - including in bars, restaurants, and other workplaces, as well as in the home - based on blood levels of a nicotine byproduct called cotinine. They found that high blood cotinine levels were associated with a 50 to 60 percent higher risk of coronary heart disease. Previous studies had estimated increased risk at 25 to 30 percent. The new study is one of the few that has sought to account for all sources of exposure to secondhand smoke, not just home exposure.
These findings add to already strong evidence that exposure to secondhand smoke increases the risk of heart disease in non- smokers. A study published in The British Medical Journal in April found that the number of heart attacks reported in Helena, Montana, fell by 40 percent during a six-month period in 2002 when the city's comprehensive smoke-free law was in effect (the law is on hold due to a legal challenge). Because of this and other evidence that even short-term exposure to secondhand smoke can trigger heart attacks, experts at the U.S. Centers for Disease Control and Prevention published a commentary in the same issue of The British Medical Journal that advised persons with heart disease to avoid indoor settings where smoking is allowed. The CDC estimates that secondhand smoke causes 35,000 heart disease deaths a year in the United States and expects to revise that estimate upward as a result of the Helena study.