A group of 1,041 children, aged 5 to 12 years with mild to moderate persistent asthma, were tested with annual spirometry tests with methacholine to work out their airway responsiveness.
Over nine years, the team from Brigham and Women’s Hospital and Harvard Medical School and colleagues, identified a clear pattern.
As the girls grew older, their reactivity to methacholine remained unchanged while the boys needed bigger doses to prompt a response. This suggests a possible decrease in disease severity, noted lead researchers Dr Kelan Tantisira in the American Journal of Respiratory and Critical Care Medicine. By age 16, the boys required twice as much methacholine to provoke a 20% constriction in their airways on average as girls did.
By 18, 27% of the boys were not responding to the methacholine challenges but only 14% of girls did not respond.
‘Our results 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,’ said Dr Tantisira.