Twenty-eight percent of American adults, and nine percent of teens, use tobacco products, according to a new survey. Researchers found 40 percent of people who use tobacco say they use more than one product. Cigarettes and e-cigarettes are the most common combination. Cigarette smoking continues to be the most common form of tobacco use, researchers at the Roswell Park Cancer Institute in Buffalo, New York, reported in the New England Journal of Medicine. HealthDay reports among adults, 23 percent smoke cigarettes and 7 percent of those smokers also use e-cigarettes. Among teens, 13 percent smoke regular cigarettes, and 11 percent also use e-cigarettes.