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Childhood asthma afflicts millions of children within the United States, with 9.5 percent of the children population dealing with this respiratory complication according to the Centers for Disease Control and Prevention. The role of genetics has always played a factor with children from a history of respiratory problems having a higher risk in developing asthma. In a new study, researchers linked the presence of a genetic variation and childhood wheezing to being markers for a child's risk in getting asthma by six-years-old.

The researchers, headed by Carole Ober, Ph.D. from the University of Chicago, evaluated two groups of children. The first group was composed of 200 American children who were considered to be high risk for asthma because they had one parent who had respiratory allergies, asthma, or both, and the researchers followed their health from birth to six-years-old. The second group had 297 Danish children with mothers that had asthma. They were monitored from birth to the age of seven. In the first group of participants, the researchers looked at the relationship between genes, wheezing from viral infections, and asthma.

The researchers found that when the children carried two at-risk alleles, their chances of developing asthma rose to 50 percent. The children with one at-risk allele had a 40 percent risk and the children who did not have either had a slightly lower than 30 percent risk. The researchers also noted that children with two copies of the genetic variation experienced more wheezing due to the human rhinovirus infection (HRV). They found that children who had both alleles and HRV related wheezing for the first three years of life had a 90 percent chance of developing asthma. The percentage went down to 60 for children with one allele and to 40 for children with no genetic risk factors. The researchers found similar statistics with the Danish group of children, with the percentages being slightly lower.

Based from these findings, the researchers attempted to see if any of the risk factors, particularly the HRV-related wheezing could be prevented. However, the researchers could not find any direct link between the development of HRV-wheezing and parents' actions. Ober stated that although parents might be able to prevent their children from getting colds, "perhaps they could work with their pediatricians to find proactive ways to prevent wheezing in young children with the asthma genotype."

The study was published in the New England Journal of Medicine.