PURPOSE OF THE STUDY.
To assess diversity and characterize stool bacteria during the first year of life in relation to the prevalence of allergic disease in school-age children.
The children in the current study are a subset of a larger study of infants with a family history of allergic disease conducted in Sweden between 2001 and 2005. Study participants received either Lactobacillus reuteri ATCC 55730 or placebo daily from day 1 to 3 of life until 12 months of age. Stool samples were collected at ages 5 to 7 days, 1 month, and 12 months. At 2 years of age, 20 children with immunoglobulin E (IgE)-associated eczema and stool samples available from all 3 sampling occasions, as well as 28 randomly selected children without allergic manifestations, were identified for 7-year follow-up. Forty-seven of the planned 48 children completed 7-year follow-up. Seventeen children belonged to the probiotic group, and 30 belonged to the placebo group. The patient who dropped out did not have allergic manifestations at 2 years. All children were breastfed for at least 1 month, and no children received antibiotics before 1 month of age. Data on gender, birth order, method of delivery, family history of allergic disease, breastfeeding, pets in the home, antibiotic use, probiotic supplementation, and infection history during the first 2 years of life were gathered for each patient.
Stool microbial diversity and composition was analyzed with 16S rDNA 454 pyrosequencing. Clinical evaluation at 7 years of age included structured interviews related to allergic disease, physical examination, spirometry, measurement of fractional exhaled nitric oxide, and skin prick testing with egg white, milk, cat, dog, Birch, peanut, mite, and timothy extracts.
Children who developed asthma (n = 8) had lower diversity of the total stool microbiota than nonasthmatic children at 1 week (P = .04) and 1 month (P = .003) of age. Asthma was not associated with total stool microbiota diversity at 12 months. There was not a consistent association between asthma at 7 years and the diversity of different stool bacterial phyla at any age. Allergic rhinoconjunctivitis, skin prick test reactivity, eczema, and IgE-associated eczema at 7 years were not associated with stool microbiota diversity during the first year of life.
Low intestinal microbial diversity during the first month of life is associated with increased risk of asthma, but not allergic rhinoconjunctivitis, skin prick test reactivity, or eczema in children at 7 years of age. Factors that affect gut microbial colonization in infancy may also affect asthma development in childhood.
Low gut microbiota diversity in infancy has previously been associated with IgE-associated eczema at age 2 in the same patient cohort. The longitudinal nature of the current study is interesting because similar previous studies have primarily performed clinical follow-up only in young children. Although the authors acknowledge limitations regarding the number of patients in the current investigation, they raise intriguing questions about long-term impact of early gut microbial diversity, mucosal barrier function, and immune system maturation.
- Copyright © 2015 by the American Academy of Pediatrics