Early Bacterial Infection May Boost Asthma Risk

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Once these children reached 5 years old, the prevalence of asthma was 33 percent for those who had earlier bacterial infections, compared to 10 percent for those who hadn't been infected.

"There are two possible interpretations: either this finding suggests that the initiating events of asthma and allergy are caused by bacterial colonization -- in analogy with the discovery that ulcer was caused by the Helicobacter pylori infection -- or this association between bacterial colonization in neonates and later development of asthma is [the result of underlying asthma and a deficient immune response to the bacteria]," Bisgaard said.

Dr. Erika von Mutius is a professor of pediatrics at University Children's Hospital in Munich, Germany, who wrote an accompanying editorial in the journal. She said it is hard to tell from this study "whether [bacteria] really are a causal factor or merely an indicator that the disease is developing."

In her editorial, von Mutius wrote, "In my opinion, the data presented by Bisgaard and colleagues may be interpreted to suggest that bacterial colonization of the [throat] in the first four weeks of life indicates a defective innate immune response very early in life, which promotes the development of asthma."

Whether bacterial infections in the first month of life are a cause of asthma or simply a sign of an already susceptible immune system, Bisgaard said early colonization with bacteria could be an early warning of a child who's at risk of developing asthma. He and his colleagues are planning to conduct a randomized, controlled trial to see if using probiotics (dietary supplements or foods containing beneficial bacteria normally found in the body) to prevent these bacterial infections could reduce the risk of asthma.

More information

To learn more about the potential causes of asthma, visit the U.S. National Heart, Lung, and Blood Institute.