Antibiotic use linked to asthma

An infant’s risk for developing asthma increases slightly with each new course of antibiotics prescribed during the first year of life, data from a recently published trial indicated.

“This study provides evidence that the use of antibiotics in the first year of life is associated with a small risk for developing asthma, and that this risk increases with the number of courses of antibiotics prescribed,” the researchers wrote.

Administrative data from a birth cohort of 251,817 children gathered between 1997 and 2003 were evaluated to determine antibiotic exposure and incidence of asthma among all children.

Seven percent (n=18,864) of the 108,958 children who received at least one antibiotic during the first year of life went on to develop asthma during the study follow-up period. Data also indicated that the risk for asthma increased with the number of courses of antibiotics prescribed, with children prescribed greater than four courses at highest risk (adjusted HR for > 4 courses: 1.30, 95% CI: 1.20 to 1.41).

Using Cox proportional hazard models the researchers adjusted for a wide scope of potential confounders including gender; socioeconomic status; urban or rural address; birth weight; gestational age; delivery method; frequency of physician visits; hospital visit involving surgery; visits to an allergist, respirologist or immunologist; congenital anomalies; and presence of otitis media, acute or chronic bronchitis, and upper and lower respiratory tract infections.

Increased risk was associated with all classes of antibiotics except sulfonamides.

Marra F. Pediatrics. 2009;123:1003-1010.