Duration and exclusiveness of breastfeeding and risk of childhood atopic diseases.

This study among 5828 children was performed in a population-based prospective cohort from fetal life onwards. The authors collected information on duration (<2 months, 2-4 months, 4-6 months, and Ã¢â€°Â¥6 months) and exclusiveness (nonexclusive vs exclusive for 4 months) of breastfeeding in infancy by postal questionnaires. At age 10 years, inhalant allergic sensitization and food-allergic sensitization were measured by skin prick tests, and physician-diagnosed inhalant and food allergy by a postal questionnaire. Data on parental-reported eczema were available from birth until age 10 years. Shorter breastfeeding duration was associated with an overall increased risk of eczema (P-value for trend <.05). Nonexclusively breastfed children had an overall increased risk of eczema (adjusted odds ratio [95% confidence interval]: 1.11 [1.01, 1.23]), compared with children exclusively breastfed for 4 months. Risk period-specific sensitivity analyses, additional adjustment for ointment use for eczema at age 2 months, and cross-lagged modeling showed no consistent results for disease-related modification of the exposure. Results were not modified by maternal history of allergy, eczema, or asthma (lowest P-value for interaction=.13). CONCLUSION: Shorter duration or nonexclusiveness of breastfeeding is associated with a weak overall increased risk of eczema but not allergic sensitization or physician-diagnosed allergy at age 10 years.