Environmental tobacco smoke causes about 46,000 heart disease deaths and 3,400 lung cancer deaths. Studies show that the risk of developing heart disease is about 25-30 percent higher among people exposed to environmental tobacco smoke at home or work. Secondhand smoke promotes illness, too. Children of smokers have many more respiratory infections than do children of nonsmokers. Nonsmoking women exposed to tobacco smoke are also more likely to have low-birthweight babies. Excerpted and adapted from "When Risk Factors Unite," appearing in the Stroke Connection Magazine January/February 2005 (Science update May 2008)