Infants and toddlers in low-income, rural areas may be at higher risk for second- and third-hand smoke than previously reported, according to a study supported by the National Institutes of Health. Approximately 15 percent of children in the study tested positive for cotinine, a byproduct formed when the body breaks down nicotine, at levels comparable to those of adult smokers. About 63 percent of children in the study had detectable levels of cotinine, suggesting widespread exposure to smoke. [...]