THURSDAY, Oct. 2, 2008 (HealthDay News) -- Young children who wheeze when they have rhinovirus infection -- the most common cause of colds -- are at much greater risk of developing asthma later during childhood, a new study says.
Previous research had shown that infants who experience viral respiratory illnesses with wheezing are more likely to develop asthma. But, until now, it has not been clear whether all types of respiratory viruses that produce wheezing are associated with this increased risk.
A new study published in the first issue for October of the American Journal of Respiratory and Critical Care Medicine found that it is rhinovirus-produced wheezing that parents should be most worried about.
"We have found that rhinovirus, the most common cause of colds, contributes a disproportionate amount toward future asthma development in comparison to other viruses that also cause childhood wheezing," principle investigator Dr. Robert F. Lemanske Jr., head of the Division of Pediatric Allergy, Immunology, and Rheumatology at the University of Wisconsin School of Medicine and Public Health, said in an American Thoracic Society news release.
The researchers followed a group of nearly 300 newborns with one or both parents who have allergies or asthma, making the newborns at increased risk for asthma. The children were followed until they were 6 years old, while the researchers evaluated them for the presence of respiratory viruses and the development of asthma.
At age 6, 28 percent of the kids had asthma, with a disproportionate amount of them having wheezed from rhinovirus.
The children who wheezed with rhinovirus during the first year of life were nearly three times as likely to have asthma when they were 6 years old, compared with children who wheezed with respiratory syncytial virus (RSV, another common respiratory ailment) who did not have increased asthma risk.
The older the children were when the rhinovirus-associated wheezing occurred, the greater the effect, the study found.
Children who wheezed with rhinovirus in their second year of life were more than six times as likely to have asthma, and rhinovirus-associated wheezing at age 3 was associated with a more than 30-fold increased risk.
While these findings provide important information about the type of wheezing-inducing virus that is associated with an increased risk of asthma, the researchers said they can't say whether rhinovirus causes asthma to develop or simply reveals children who will develop the disease.
"In genetically susceptible children, [rhinovirus] wheezing illnesses could cause airway damage as well as subsequent asthma (virus-related factors)," Dr. Daniel L. Jackson, Allergy and Immunology Fellow at the University of Wisconsin, said in the news release. But Jackson pointed out that additional research is needed to determine whether rhinovirus leads to asthma development.
The American Lung Association has more about childhood asthma.