Antibiotic Use in Infants May Up Asthma Risk

The drugs might kill off bad and good bacteria, study suggests.

By Serena Gordon
HealthDay Reporter
Monday, June 11, 2007; 12:00 AM

Copyright © 2007 ScoutNews, LLC. All rights reserved.

MONDAY, June 11 (HealthDay News) -- Giving antibiotics for a non-respiratory tract infection to an infant younger than 1 greatly increases the odds that the child will develop asthma, according to new research.

The study found that the risk was highest for those infants who received multiple courses of antibiotics and those who received prescriptions for broad-spectrum antibiotics. Broad-spectrum antibiotics tend to kill a wide range of bacteria -- both good and bad.

"Asthma is a multi-factorial disease, and we've found evidence of an association with first-year-of-life antibiotic use and asthma," said the study's lead author, Anita Kozyrskyj, an associate professor at the University of Manitoba in Winnipeg, Canada.

One hypothesis, Kozyrskyj added, is that broad-spectrum antibiotics are killing off too many good bacteria.

"It may be that you need the presence of good bacteria during the first year of life for the immune system to develop normally, and the antibiotics are killing off some of the natural microflora in the gut," she said.

The study findings are published in the June issue of the journal Chest.

Each year, about 4 million American children have active asthma, resulting in about 14 million missed school days, according to the American Lung Association. Because asthma can't currently be cured, only controlled, researchers are focusing on factors that may play a role in the initial development of the lung disease.

For the new study, Kozyrskyj and her colleagues followed almost 14,000 children from birth in 1995 until 2003, when all of the children had reached 7 years of age. Data came from the Manitoba Health Services Insurance Program and included information on physician visits, prescriptions, hospitalizations and health diagnoses.

Additionally, the researchers linked this data to data on the mothers of these children to see if there was a maternal history of asthma. Parents also completed surveys on home and environmental exposures.

All of the children were from Manitoba. Half were male, and 57 percent lived in urban areas. One-quarter of the children were from low-income families; 90 percent had siblings; 5 percent had a maternal history of asthma, and 6 percent developed asthma by age 7, the researchers found.