Researchers at the University of Manchester in England studied 771 children at age 3 and again at age 5, and found children who developed wheezy symptoms after 3 years of age were more likely to have significant behavior problems before they started wheezing, compared with children who had never wheezed.
"There is now a substantial body of evidence indicating that children with asthma have higher levels of behavior problems compared to non-asthmatic children," said lead researcher Rachel Calam, Ph.D. "However, it is unclear whether behavior problems are a contributing factor for asthma development, or a consequence of the disease."
In a previous study, Dr. Calam and colleagues found that at age 3 the risk of recurrent wheeze increased significantly with elevated behavior problems ratings. However, the researchers were not able to determine whether behavior problems brought on wheezing, or whether wheezing caused the behavior problems.
When the children were 3, the children's parents had answered a questionnaire about 36 common behavioral problems (such as whether their child had temper tantrums, constantly sought attention, or was easily distractible). They also rated how often the specific behaviors occurred. In the new study, the researchers looked at asthma symptoms at age 5, comparing these to the behavior ratings from age 3.
"Our findings do not necessarily mean that behavior problems cause wheeze," Dr. Calam noted. She said there may be some common factor that accounts for the presence of wheezing and behavior problems, such as a genetic link, or parental smoking, which is associated with both problem behavior and risk of wheeze in children.
"Our findings are consistent with another major study recently which showed that behavioral disturbance was reported before the development of wheeze and was not a secondary psychological reaction to disease," Dr. Calam said. "We need to understand potential relationships much better, so that we can identify the right sorts of interventions to help families."