Autumn Babies More Prone to Asthma
Nov. 22 -- FRIDAY, Nov. 21 (HealthDay News) -- The season of a baby's birth may help predict that child's risk of asthma, new research suggests.
Babies born in autumn -- about four months before the peak of winter virus season -- have almost a 30 percent increased risk of asthma compared to babies born at other times of the year, reports a study in the first December issue of the American Journal of Respiratory and Critical Care Medicine.
"Children in the Northern hemisphere born in the fall months have the highest rates of asthma, which suggests that winter viruses, like RSV, cause asthma," said study senior author Dr. Tina Hartert, director of the Center for Asthma Research and Environmental Health at Vanderbilt University School of Medicine, in Nashville, Tenn.
"What we need to prove now is that preventing these viruses could prevent asthma," she added.
Respiratory syncytial virus (RSV) is a very common infection. In fact, Hartert said that about 70 percent of U.S. infants will have an RSV infection before their first birthday. Not all children who have an RSV infection will develop asthma, but those with more severe infections appear to have a higher risk. More than 40 percent of infants hospitalized for a respiratory virus develop asthma by their teen years, according to background information in the study.
The author of an accompanying editorial in the same issue of the journal said genetic factors play a role as well. "Asthma, like many other complex diseases, has a genetic background that is importantly affected by the surrounding environment. Different factors, like allergies or maternal/paternal history of asthma, when in combination with early life infections by respiratory viruses, seem to increase substantially the risk for asthma, or at least, persistent wheeze," said Dr. Renato Stein, head of the pediatric pulmonary service at Pontificia Catholic University in Porto Alegre, Brazil.
What hasn't been clear in the past is whether RSV and other viruses actually cause asthma, or whether children who are predisposed to asthma are the ones most likely to get such viruses, according to Dr. Jennifer Appleyard, chief of allergy and immunology at St. John Hospital in Detroit.
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