The introduction of allergenic foods and the development of reported wheezing and eczema in childhood: the Generation R study.

OBJECTIVE To examine whether the timing of introduction of the allergenic foods cow's milk, hen's egg, peanuts, tree nuts, soy, and gluten is associated with eczema and wheezing in children 4 years of age or younger. DESIGN Population-based prospective cohort study from fetal life until young adulthood. SETTING Rotterdam, the Netherlands, from April 2002 through January 2006. PARTICIPANTS A total of 6905 preschool children participating in the Generation R study. MAIN EXPOSURE Timing of introduction of cow's milk, hen's egg, peanuts, tree nuts, soy, and gluten collected by questionnaires at 6 and 12 months of age. MAIN OUTCOME MEASURES Information on the outcomes eczema and wheezing were obtained by questions from the age-adapted version of the "International Study of Asthma and Allergies in Childhood" core questionnaire and questionnaire data on parentally reported physician diagnosis for eczema. RESULTS Of 6905 children, wheezing was reported in 31% at age 2 years and in 14% at ages 3 and 4 years. Eczema was reported in 38%, 20%, and 18% of children at the ages of 2, 3, and 4 years, respectively. The introduction of cow's milk, hen's egg, peanuts, tree nuts, soy, and gluten before the age of 6 months was not significantly associated with eczema or wheezing at any age after adjustment for potential confounders (P > .10 for all comparisons). The results did not alter after stratification according to the child's history of cow's milk allergy and parental history of atopy. CONCLUSION This study does not support the recommendation for delayed introduction of allergenic foods after age 6 months for the prevention of eczema and wheezing.