Background: The results of numerous studies on the influence of breastfeeding in the prevention of atopic disorders are often contradictory. One of the most important problems is confounding by other lifestyle factors.

Objective: The aim of the present study was to analyse the effect of any breastfeeding duration on the prevalence of atopic eczema in the first seven years of life taking into account other risk factors.

Methods: In an observational birth cohort study 1314 infants born in 1990 were followed-up for seven years. At 3, 6, 12, 18, 24 months and every year thereafter, parents were interviewed and filled in questionnaires, children were examined and blood was taken for in vitro allergy tests. Generalized Estimation Equations (GEE)-models were used to model risk factors for the prevalence of atopic eczema and for confounder adjustment

Results: Breastfeeding was carried out for longer if at least one parent had eczema, the mother was older, did not smoke in pregnancy, and the family had a high social status. The prevalence of atopic eczema in the first seven years increased with each year of age (OR 1.05; 95% CI 1.01-1.09 for each year), with each additional month of breastfeeding (1.03; 1.00-1.06 for each additional month), with a history of parental atopic eczema (2.06; 1.38-3.08), and if other atopic signs and symptoms appeared, especially specific sensitization (1.53; 1.25-1.88), and asthma (1.41; 1.07-1.85). Although breastfeeding should be recommended for all infants, it does not prevent eczema in children with a genetic risk.

Conclusion: Parental eczema is the major risk factor for eczema. But in this study, each month of breastfeeding also increased the risk.