RESUMEN
Breast feeding (BF) provides many advantages to the offspring; however, at present there is an ongoing debate as to whether or not it prevents allergic diseases. The aim of the current study was to investigate the effect of duration of BF on eczema in the first year of life. A birth cohort of 1128 infants was followed prospectively from 5 months of pregnancy. Data were collected using questionnaires, a medical examination and blood tests for allergy at the age of 1 yr. Breast feeding was not statistically significant associated with eczema in the first year of life [adj ORs with 95% CIs: 0.8 (0.4-1.3), 0.8 (0.5-1.3) and 1.0 (0.6-1.5) for BF duration of 1-6 wk, 7-12 wk and > or = 13 wk, respectively]. Eczema was positively associated with atopy and educational level of the mother, use of antibiotics in pregnancy and passive smoking by the child during the first 12 months. Regular postnatal contact of the infants with dogs was inversely associated with eczema. Breast feeding was positively associated with eczema among children with non-atopic parents [adj ORs with 95% CIs: 2.1 (0.4-10.6), 2.2 (0.4-11.3) and 1.9 (0.4-8.5) for BF duration of 1-6 wk, 7-12 wk and > or = 13 wk, respectively], whereas an inverse association was found among children with atopic parents [adj ORs with 95% CIs: 0.6 (0.3-1.3), 0.7 (0.3-1.4) and 0.9 (0.5-1.7) for the same BF durations]. However, these associations were not statistically significant. Breast feeding has no significant effect on the prevalence of eczema in the first year of life. The effect of BF on eczema in children depends on parental atopy.