Background: To examine the social determinants of infant smoke exposure and whether these associations vary by mothers' smoking status and number of children in the household.
Methods: There were 135 278 mothers from 28 states who participated in the Pregnancy Risk Assessment Monitoring System from 2000 to 2003.
Results: Overall 9.9% of mothers reported that her infant was in the same room as someone smoking for 1 or more hours per day. Among smoking households, infants with 1 or 2+ siblings were 25% and 59% more likely to be exposed to 1+ hours of second-hand smoke daily, respectively, than infants with no siblings.
Conclusion: Infants only a few months old are being exposed to second-hand smoke, particularly infants whose mother smokes and infants with siblings, indicating the importance of surveillance even for this young age group.
Keywords: infant; second-hand smoke.
© 2013 John Wiley & Sons Ltd.