Allergen and Bacterial Exposure During the First Year of Life Is Inversely Associated with Recurrent Wheeze

Growing up in an agricultural setting with livestock and accompanying bacteria is thought to protect against allergic disease, while exposure to allergens such as dust mites, cockroaches, and rodents might increase risk. In a longitudinal birth cohort study, investigators examined the relation between early exposures to allergens and bacteria and recurrent wheeze and atopy in 506 children with atopic family histories in four U.S. urban areas.

From birth to age 3 years, specific IgE levels, skin tests, and questionnaires were collected annually, and participants' homes were examined for allergen content. Overall, 44% of children were sensitized to at least one aeroallergen, 36% had recurrent wheeze, and 9% had eczema. Recurrent wheeze was ass…