SAN DIEGO – Antibiotic use prior to 6 months of age was associated with recurrent wheeze but not with allergic sensitization or other clinical allergic outcomes, results from a large birth cohort study demonstrated.
"In the medical literature, some but not all studies suggest that antibiotic use early in life is related to later childhood asthma and allergic disease," Kyra Jones, M.Ed., said at the annual meeting of the American Academy of Allergy, Asthma, and Immunology.
"It is well known that antibiotics affect the gut microbiome," she added. "What may not be as clear is the impact of the effect and its relationship to allergic outcomes. Since antibiotics affect the gut microbiome, we hypothesized that early antibiotic use would be associated with allergic outcomes."
Krya Jones, M.Ed.
In an effort to determine whether antibiotic use in the first 6 months of life is associated with allergic sensitization or clinical allergic outcomes at age 2-3 years, Ms. Jones, an epidemiologist in the department of public health sciences at Henry Ford Hospital, Detroit, and her associates obtained data from 1,258 pregnant women who participated in the WHEALS (Wayne County Health, Environment, Allergy, and Asthma Longitudinal Study) prospective birth cohort.
The women, who ranged in age from 21 to 49 years, were recruited between 2003 and 2007 at one of five Henry Ford Health System obstetric clinics in the western Wayne County suburbs or the city of Detroit. They were interviewed at 1, 6, 12, and 24 months following the birth of their child. Next, their children were brought into the clinic at 2-3 years of age and assessed for atopic dermatitis. The researchers analyzed the children’s blood for total IgE and specific IgE to milk, egg, peanut, dog, cat, dust mite, timothy grass, and cockroach and performed skin prick tests for the same allergens.
The primary exposure was defined as the mother reporting that her child had taken one or more of the following antibiotics within the first 6 months of life: cephalosporins, macrolides, penicillin, sulfonamides, and topical antibiotics. Outcomes of interest included total IgE, specific IgE, skin prick test positivity, history of physician diagnosis of atopic dermatitis, and parental report of wheezing at least twice in the first 2-3 years of life – including at least once in the preceding year. The researchers used logistic and linear regression models to assess associations between antibiotic exposure and outcomes.
Ms. Jones reported data from 680 children. More than half (58%) were African American and 51% were male. Slightly more than half (51.2%) had a positive specific IgE, 24.5% had a positive skin prick test, 22.7% had atopic dermatitis, and 15.6% had recurrent wheezing.
At 2 years, most outcomes were similar between children who used antibiotics and those who did not, but 22% of children who took antibiotics had recurrent wheeze, compared with 14% of those who did not, a difference that reached statistical significance (P = 0.03). Multivariate models revealed similar findings (odds ratio of 1.85 for recurrent wheeze in children who received antibiotics vs. those who did not; P = 0.019).
Strengths of the study, Ms. Jones said, include a geographically based, diverse population, while a key limitation was the fact that the children were examined at 2-3 years of age. "This is a little early to diagnose asthma," she noted. "These children have not fully developed their asthmatic and atopic characteristics, so we have to look at them when they’re a little older. Another limitation is the possibility that some of the antibiotics were given for respiratory conditions that were actually early symptoms of asthma."
Ms. Jones said that she had no relevant financial disclosures.