Background: The association between breastfeeding and the risk of atopic diseases in children is controversial. While some studies support the theory of a decreased risk of asthma and allergic diseases due to breastfeeding, others have failed to confirm such a protective effect, and even suggest increased risk. The aim of this longitudinal study was to investigate the association between breastfeeding and the prevalence of atopic diseases in 2-year-old children.

Methods: Data on 1685 children from a birth cohort were collected from questionnaires completed by parents at birth and at 6, 12, and 24 months. By means of logistic regression and considering confounders such as family history and socioeconomic status, we analyzed the association between exclusive breastfeeding and the development of allergic reactions in 2-year-old children.

Results: Exclusive breastfeeding for >4 months was associated with an increased risk of asthma and atopic dermatitis in children without a parental history of allergic diseases (odds ratio [OR]=1.62; 95% confidence interval [CI], 1.02-2.56). Children whose fathers only had a history of allergic disease strongly benefited from exclusive breastfeeding for >4 months (OR=0.39; 95%-CI: 0.18-0.83) whereas those whose mothers only had such a history had an increased risk of asthma and atopic dermatitis (OR: 2.31; 95%-CI: 1.16-4.60).

Conclusion: In children with a family history of allergy, it seems to be important to distinguish between maternal and paternal predisposition as children whose fathers have a history of atopic disease seem to benefit most from breastfeeding for >4 months.

Key words: Breastfeeding. Parental history. Allergy. Children.