Infants and toddlers in low-income communities may be even more at risk from second- and third-hand smoke exposure than has been believed, according to new federally supported research. In testing that included more than 1,200 children, researchers found that up to 15 percent of them had levels of cotinine, a byproduct of the body's breakdown of nicotine, comparable with what would be found in an adult smoker.

Overall, about 63 percent of the babies and young children in the study had discernible levels of cotinine, [...]