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.