Breastfeeding and the prevalence of symptoms of allergic disorders in Japanese adolescents.

BACKGROUND: Environmental factors acting early in life are key determinants of the incidence of allergic disease. Whether breastfeeding is protective against allergic disorders remains controversial.

OBJECTIVE: The present cross-sectional study examined the relationship between feeding patterns in the first 3 months of life and the prevalence of symptoms of wheeze, atopic eczema, and rhinoconjunctivitis during the past 12 months in Japanese adolescents.

METHODS: The subjects were 5614 of 9008 students (62%) aged 12-15 years from all public junior high schools in Suita, Japan in 2001. This study used the diagnostic criteria of the International Study of Asthma and Allergies in Childhood. Adjustment was made for gender, grade, number of older siblings, and parental history of allergy.

RESULTS: Feeding pattern was unrelated to the prevalence of wheeze or rhinoconjunctivitis. The prevalence of atopic eczema was significantly higher in children who had been breastfed than in artificial milk feeders (adjusted odds ratios = 1.40 and 1.56, 95% confidence intervals: 1.01-1.98 and 1.13-2.22 for mixed milk intake and breastfeeding only vs. artificial milk consumption, respectively; P = 0.01 for linear trend). When children were divided according to a positive or negative allergic history in at least one parent, an increased prevalence of atopic eczema associated with breastfeeding was found in children with a negative parental allergic history compared with those with a positive parental allergic history.

CONCLUSION: The findings suggest that breastfeeding may be associated with an increased prevalence of atopic eczema, especially among children without a parental history of allergy.