PURPOSE OF THE STUDY.
To evaluate the association between duration of breastfeeding (BF) and introduction of complementary foods on the development of asthma and other allergic conditions by the age of 5 years.
The study population consisted of 3781 Finnish children already enrolled in the Finnish Type 1 Diabetes Prediction and Prevention study, a multicenter, prospective, population-based cohort study that recruited children with HLA-conferred susceptibility to type 1 diabetes mellitus. Those who were still actively participating in the dietary study at age 5 years were invited to participate in the allergy study.
Parents were asked to complete age-specific dietary questionnaires that assessed pattern of BF, use of infant formula, cow’s milk, dietary supplements, and other complementary foods consumed at ages 3, 6, and 12 months, respectively. Additionally, an “age at introduction of new foods form” was kept by parents and recorded dietary history up to age 2 years. Then at age 5 years, children were assessed for asthma or other allergic diseases using a modified form of the International Study of Asthma and Allergies in Childhood questionnaire, as well as clinical history of physician-diagnosed asthma, allergic rhinitis (AR), and/or atopic dermatitis (AD). Additionally, specific immunoglobulin E testing (via ImmunoCAP analysis) was performed to a select number of food and inhalant allergens with atopic sensitization defined as a serum level >0.35 kU/L to each allergen tested.
Of 3781 children in the study, 6.2% had asthma, 37.0% had AD, and 14.0% had AR, with 38.0% sensitized to any allergen. The median duration of exclusive BF was 1.4 months (0.2–3.5 months), with total duration of BF of 7 months (4–11 months). A total time of BF of ≤9.5 months showed an increased risk of nonatopic asthma. The introduction of cow’s milk (median age 1.8 months), as well as cereals, including maize, rice, millet, and buckwheat, by 4 months of age, was associated with the development of AD. Introduction of wheat, rye, oat, and barley cereals by 5.0 to 5.5 months was inversely associated with atopic disease, including asthma, AR, and atopic sensitization. Introduction of egg (<11 months) was inversely associated with asthma, AR, and atopic sensitization, whereas introduction of fish (<9 months) was inversely associated with AR and atopic sensitization.
Results indicate that a longer duration of BF appears to be protective against the development of nonatopic asthma. Overall, early introduction of certain cereals (wheat, rye, oat, barley), fish, and egg appears to infer protection from asthma and atopic disease by age 5 years.
This study confirms the importance of BF in reducing risks of atopy, and it also shows a new finding that total BF rather than exclusive BF may be most important. The results also underscore the value of continued study of mucosal immunity in infants and the role of early dietary introduction of specific foods.
- Copyright © 2013 by the American Academy of Pediatrics