Are antibiotics fueling an increase in asthma?

Antibiotic use during the first year of life can be associated with up to double the likelihood of childhood asthma, according to a retrospective, population-based study.

Researchers recently found that the more antibiotics prescribed during the first year of life, the greater the risk of asthma became. Children prescribed 5 or more courses had double the odds of persistent asthma (ie, beginning before age 3 years and persisting through age 4 to 7 years) compared with children who took no antibiotics during their first 12 months of life.

Any antibiotic use during the first year was associated with double the risk of transient wheezing and a 60% increase in the risk of persistent asthma. The investigators found no association with late-onset asthma (ie, beginning after age 3 years).

The researchers looked at more than 62,000 children continuously enrolled in a nationwide employer-provided health insurance plan from birth until at least age 5 years. The population was largely urban, and the study did not control for family smoking or birth route (ie, vaginal or cesarean delivery). A full 43% of the study population had at least 1 course of antibiotics before their first birthday.

The investigators were careful not to conclude cause and effect, commenting that it may be that young children who are susceptible to problems requiring antibiotics may be more prone to asthma. They also noted that their findings are consistent with the “hygiene hypothesis,” which basically states that as young children are exposed to fewer microbes, they will develop more atopic disease in childhood.

The researchers emphasize that antibiotics should only be prescribed for infants if absolutely necessary.

According to the National Institute of Allergy and Infectious Diseases, asthma affects about 7 million children. May is Asthma Awareness Month.

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