Reduced gut microbial diversity in early life is associated with later development of eczema but not atopy in high‐risk infants

Background: Alterations in intestinal microflora have been linked to the development of allergic disease. Recent studies suggest that healthy infant immune development may depend on the establishment of a diverse gut microbiota rather than the presence or absence of specific microbial strains. Objectives: We investigated the relationship between diversity of gut microbiota in the early postnatal period and subsequent development of eczema and atopy in the first year of life. Methods: Fecal samples were collected 1 wk after birth from 98 infants at high risk of allergic disease, who were followed prospectively to age 12 months. Fecal microbial diversity was assessed by terminal restriction fragment length polymorphism (T‐RFLP) using restriction enzymes Sau96I and AluI, with a greater number of peaks representing greater diversity of bacterial communities. Results: Microbial diversity at day 7 was significantly lower in infants with eczema at age 12 months as compared to infants without eczema (AluI mean number of peaks 13.1 vs. 15.5, p = 0.003, 95% CI for difference in means ?3.9, ?0.8; Sau96I 14.7 vs. 17.2, p = 0.03, 95% CI ?4.9, ?0.3). No differences were observed for atopic compared to non‐atopic infants, or infants with two allergic parents compared to those with one or no allergic parent. Conclusions: A more diverse intestinal microbiota in the first week of life is associated with a reduced risk of subsequent eczema in infants at increased risk of allergic disease. Interventions that enhance microbial diversity in early life may provide an effective means for the prevention of eczema in high‐risk infants.     

Early childhood infections and immunisation and the development of allergic disease in particular asthma in a high‐risk cohort: A prospective study of allergy‐prone children from birth to six years

Thomson JA, Widjaja C, Darmaputra AAP, Lowe A, Matheson MC, Bennett CM, Allen K, Abramson MJ, Hosking C, Hill D, Dharmage SC. Early childhood infections and immunisation and the development of allergic disease in particular asthma in a high‐risk cohort: a prospective study of allergy‐prone children from birth to six years.
Pediatr Allergy Immunol 2010: 21: 1076–1085.
© 2010 John Wiley & Sons A/S The role of early childhood infections and immunisation in the development of allergic diseases remains controversial. To examine these associations, six hundred and twenty infants with first‐degree relatives with allergic diseases were recruited into the Melbourne Atopy Cohort Study. Information on risk factors and outcomes was collected by interviewer administered questionnaire and was based on parental report and/or a physician’s diagnosis. Risk factors examined included early childhood infections (including gastroenteritis, otitis media and lower respiratory tract infections) and immunisations in the first 2 yr of life. Outcomes were current asthma, allergic rhinitis and eczema at 6 yr of age. Univariate and multivariate regression analysis were used to estimate relative risk (RR) and assess confounding. By 6 yr, 79% of the original cohort remained in the study. Those with at least three episodes of gastroenteritis showed an increased risk (crude RR 2.36, 95%CI 1.41 3.95; adjusted RR 2.03 95%CI 1.50 2.75) for the later development of asthma at age 6. Of the scheduled immunisations, Sabin immunisation in the second year had a reduced risk of asthma at 6 yr (crude RR 0.60, 95%CI 0.37 0.98; adjusted RR 0.63 95%CI 0.39 1.02). Combined diphtheria and tetanus (CDT) immunisation in the first year had an increased risk of asthma at 6 yr (RR 1.76, 95%CI 1.11 2.78; adjusted RR 1.88 95%CI 1.28 2.77). Recurrent gastroenteritis in early childhood is associated with a later risk of asthma. This may reflect a cause and effect relationship, or exposure to common risk factors. In contrast, Sabin immunisation in the second year is associated with a decreased risk of asthma in later childhood. CDT immunisation in the first year may be a risk factor for asthma, but the need for CDT immunisation may also be a marker of increased risk of asthma in later childhood.