A study looking at the differences in the disease in both sexes revealed that boys are more likely than girls to beat asthma by adolescence.

Despite the fact that boys are more predisposed to childhood asthma, the study showed that more boys than girls grew out of the condition during puberty.

“We want to investigate what was behind the observed sex differences in asthma rates and AR. This is the first study to prospectively examine the natural history of sex differences in asthma in this manner,” Lead researcher, Kelan G. Tantisira, M.D., M.P.H., of Brigham and Women’s Hospital and Harvard Medical School, said.

The study was based on data from the ongoing Childhood Asthma Management Program (CAMP) that involved 1041 children from 5 to 12 years of age with mild to moderate persistent asthma. The children performed annual spirometric testing with methacholine challenges to quantify their airway responsiveness (AR).

After almost 9 years, boys became increasingly tolerant over time to larger and larger doses of methacholine, which is known to provoke airway constriction. This suggested a possible decrease in disease severity.

The study found that at age 16, it took more than double the dose to provoke a 20 percent constriction in the boys’ airways as it did in girls. By the age of 18, only 14 percent of the girls did not react to the drug compared with 27 percent of boys.

“While our results were not unexpected, they do point to intriguing potential mechanisms to explain the gender differences in asthma incidence and severity. Especially intriguing is that the differences in gender begin at the time of transition into early puberty,” Dr. Tantisira said.

The children will be followed into adulthood.

The findings of the study appeared in the second issue for August of the American Journal of Respiratory and Critical Care Medicine published by the American Thoracic Society.