WEDNESDAY, Oct. 15, 2003 (HealthDayNews) -- While boys account for nearly two of three children with severe asthma, more than two of three adults with severe asthma are women.
The reasons for that gender shift between childhood and adulthood aren't clear, says a study in the October issue of Chest.
Researchers from National Jewish Medical and Research Center also found children with severe asthma had surprisingly good airflow in and out of their lungs. That indicates that even children seriously ill with asthma could be misdiagnosed and under-treated, the study says.
"Our findings highlight many of the significant differences between severe asthma in children and adults. We hope they will spur further research that can lead to a better understanding and better treatment of this disease," lead researcher Dr. Joseph Spahn says in a prepared statement.
He and his team examined data on 275 people with severe asthma who had been referred to National Jewish. Males accounted for 62 percent of the patients under age 18, while women accounted for 68 percent of those over 18 with severe asthma.
Similar ratios have been noted in people with mild and moderate asthma. This is the first study to document the situation in people with severe asthma.
"There has been speculation that a woman's hormones or possibly differences in the size of male and female lungs play a role in this changing pattern of asthma prevalence, but no one really knows for sure why it occurs," Spahn says.
"If we could learn why, we might gain valuable insight that could help us better treat all our asthma patients," he says.
Spahn and his colleagues also found that children with severe asthma had deceptively good lung function.
One of the primary measures used to diagnose and categorize asthma is forced expiratory volume in one second (FEV1). It measures the amount of air a person can exhale in a second. People are deemed to have severe asthma when their FEV1 is less than 60 percent of the value for healthy people of the same size and age.
In this study, adults with severe asthma had an average FEV1 that was 57 percent of the healthy average. But the children with severe asthma averaged an FEV1 of 74 percent and many exceeded 90 percent.
"The good news is that children have significantly less impaired lung function than do adults with asthma. The bad news is that existing guidelines do not reflect this fact, and physicians may be mistakenly reassured by normal or near normal lung function readings in their pediatric patients," Spahn says.
"As a result, they may fail to appreciate the severity of their patients' asthma and under-treat them," he adds.
Here's where you can learn more about asthma.