Breast-feeding duration and infant atopic manifestations, by maternal allergic status, in the first 2 years of life (KOALA study).

Objective: To investigate the potential effect of modification by maternal allergic status on the relationship between breast-feeding duration and infant atopic manifestations in the first 2 years of life.
Study Design: Data from 2705 infants of the KOALA Birth Cohort Study (The Netherlands) were analyzed. The data were collected by repeated questionnaires at 34 weeks of gestation and 3, 7, 12, and 24 months postpartum. Total and specific immunoglobulin E measurements were performed on venous blood samples collected during home visits at age 2 years. Relationships were analyzed using logistic regression analyses.
Results: Longer duration of breast-feeding was associated with a lower risk for eczema in infants of mothers without allergy or asthma (P(trend) = .01) and slightly lower risk in those of mothers with allergy but no asthma (P(trend) = .14). There was no such association for asthmatic mothers (P(trend) = .87). Longer breast-feeding duration decreased the risk of recurrent wheeze independent of maternal allergy (P(trend) = .02) or asthma status (P(trend) = .06).
Conclusions: Our findings show that the relationship between breast-feeding and infant eczema in the first 2 years of life is modified by maternal allergic status. The protective effect of breast-feeding on recurrent wheeze may be associated with protection against respiratory infections.