Children in poor families are more likely to live with multiple adult smokers and therefore are at greater risk of exposure to indoor tobacco smoke, according to a new study.

HealthDay News reported April 3 that researcher Michael Weitzman of New York University and colleagues found that 49 percent of children from lower-income households lived with one or more smokers, compared to 21 percent of kids from higher-income families. Moreover, kids from poor families were more likely to live with multiple smokers.

Among children living with smokers, 59 percent had mothers who smoked, and 57 percent lived with two smokers. However, few children -- just 17 percent -- lived with smokers if their mothers did not smoke.

Among children who lived with smokers but did not live with their parents, 53 percent lived with grandparents who smoked.

The study appears in the April 2009 issue of the journal Pediatrics.