Breast-feeding is inversely associated with asthma and IgE sensitization up to young adulthood

Few studies have investigated the association between breast-feeding and asthma and allergy up to adulthood.

We examined the development of asthma and IgE sensitization up to young adulthood in relation to duration of exclusive breast-feeding in a longitudinal cohort.

The 3,919 participants in the study population were from a Swedish birth cohort with questionnaire data on breast-feeding at age 1 year. Asthma was based on questionnaire data up to age 24 years. Blood sampling for IgE analyses was performed at 4, 8, 16, and 24 years. Longitudinal analyses were performed with generalized estimating equations.

Exclusive breast-feeding for ≥4 months was associated with overall reduced odds of prevalent asthma up to age 24 years (adjusted odds ratio [OR_adj] = 0.75; 95% confidence interval [CI], 0.64-0.87). Age-specific analyses showed a statistically significant inverse association with asthma up to age 12 years, but not thereafter. Analyzing asthma phenotypes over time resulted in a borderline significant inverse association with early transient asthma and a significant inverse association with persistent asthma (OR_adj = 0.64; 95% CI, 0.48-0.84). However, there was no association with late-onset asthma. Breast-feeding was overall also inversely associated with IgE sensitization (OR_adj = 0.82; 95% CI, 0.70-0.96). Exclusion of children with early symptoms of wheeze and/or eczema during breast-feeding (n = 486) strengthened the associations for both asthma and sensitization.

Exclusive breast-feeding for ≥4 months was inversely associated with asthma, in particular with disease onset during the first 12 years of life, as well as IgE sensitization up to young adulthood.