Duration of breastfeeding, daycare, and physician visits among infants 6 months and younger.

PURPOSE To describe the association between duration of breastfeeding and an illness requiring a visit to a health care provider within the past 30 days (IRHP) among infants </= 6 months. METHODS Participants were breastfeeding women who delivered at a birthing center in suburban Detroit, Michigan and women employed by a company in Omaha, Nebraska. Subjects were interviewed by telephone at 3,6,9, and 12 weeks postpartum and by mailed questionnaire at 6 months postpartum. RESULTS Of the 674 breastfeeding women, 233 (34.5%) reported an IRHP. An IRHP was more likely among infants attending daycare (RR = 1.60; 95% CI 1.30, 1.96). There was an interaction between duration of breastfeeding, the number of children in the household, and IRHP (p < 0.0001). For firstborn children, each additional week of breastfeeding decreased the likelihood of an IRHP by 4%. An increased duration of breastfeeding was not significantly protective against an IRHP for infants living with additional children in the household. CONCLUSIONS Breastfeeding offers protection against an IRHP among firstborn children. Having additional children in the household or attending daycare outside of the home may diminish these benefits.