Secondhand smoke is in the news again, and as legislators decide whether to place even more restrictions on smokers, it might be worthwhile to take a look at some of the objective evidence on this controversial issue.
In a study published in Circulation on May 23, 2005, investigators report that the cardiovascular system of nonsmokers is extremely sensitive to tobacco toxins inhaled during passive smoking. They reached this conclusion by analyzing 29 studies that measured the risk of heart disease in people who never smoked tobacco, but who were exposed to secondhand smoke.
While secondhand smokers only inhale about 1/100th the dose of smoke inhaled by the smokers themselves, the effect of that secondhand smoke is large. Secondhand smokers have a risk of coronary heart disease that is 30% higher than for nonsmokers who are not exposed to secondhand smoke. In contrast, the risk for actual smokers is increased by 80%. So, while the dose of smoke inhaled by passive smoking is 100 times smaller than for smokers, the increase in risk to the nonsmokers is much, much greater than that. Indeed, their excess risk is almost 40% as high as the excess risk to the smokers themselves.
The investigators further listed the effects that secondhand smoke have been shown to have on the cardiovascular system that can lead to an increase in cardiac disease. These include: making platelets stickier, causing inflammation, reducing HDL cholesterol levels, increasing LDL cholesterol levels, and increasing insulin resistance. Some of these effects can be measured after just a few minutes of exposure to secondhand smoke.
The accumulating and disturbing evidence against secondhand smoke is enough to make even DrRich, an ardent supporter of individual freedoms, hope for even more restrictions on smoking in public places.