Early Antibiotic Use May be Linked to Asthma - Treatments May Lead to Childhood Asthma

March 14th 2006

Early Antibiotic Use May be Linked to Asthma - Ear Infections Bronchitis and Upper Respiratory Infection Treatments May Lead to Childhood Asthma

Asthma Patient X-ray

Researchers warn that antibiotic use may double the risk of childhood asthma. According to a study by the University of British Columbia, “children under age 1 who are treated with an antibiotic are twice as likely to develop asthma in childhood.”

Current guidelines recommend antibiotics for children under the age of 2 who contract ear infections. The study’s coauthor, Fawziah Marra, M.D, said “In children, antibiotics are commonly used to treat ear infections, upper respiratory tract infections, and bronchitis, but not every childhood infection requires an antibiotic.” Since most upper respiratory tract infections and bronchitis are viral, antibiotics are ineffective.

Previous studies involving several hundred to several thousand youngsters have suggested a link between antibiotic use and asthma. These earlier studies have been criticized for being too small, for relying on imprecise records on past antibiotic use. This new analysis combines studies to create a larger pool for extrapolating the data.

The researchers reviewed seven studies that included 12,082 children, and compared childhood asthma rates among children that received antibiotics in the first year and those that did not. They found that in retrospective studies the odds ratio was 2.82. In prospective studies the odds ratio was 1.12. Interestingly they found that infants already at high risk for asthma that took antibiotics had a lower risk of developing the condition, but the results were not significant.

A prospective study is where one or more groups (cohorts) of individuals who have not yet had the outcome event in question are monitored for the number of such events which occur over time. The retrospective study looks backwards in time.

The researchers then looked at data from five studies that included 22,167 children. They found that for “each additional prescription of antibiotics taken during the first year of life a significant overall ratio of 1.16.” This suggests that each additional course of antibiotics may increase the risk of asthma even more.

Doctor W. Michael Alberts said “By identifying potential risk factors for asthma and educating patients and families about risk factors, we may begin to see a reduction in the overall incidence of asthma." He is the President of the American College of Chest Physicians. According to the Mayo Clinic, “Antibiotics are the first line of defense against many infections, but overusing or misusing antibiotics can cause more harm than good.”