The age of onset of adult-onset asthma is increasing in Japanese women]

Although the age of onset of childhood bronchial asthma is known to be decreasing, the age of onset of adult-onset asthma has yet to be comprehensively investigated.We examined the records of 5067 asthma patients (2047 males) aged 16 years or older who visited our clinic during a recent 9-year period (1997 through 2005). The definition of adult-onset asthma (ie, new-onset persistent asthma developing at 20 years or older) was based on the Akiyama classification. We analyzed the associations between a number of putative risk factors and age of onset.Although the age of onset of adult-onset asthma did not change significantly in males (43.0+/-13.8 [mean+/-SD] years in 1997 vs 44.5+/-15.2 years in 2005), a significant increase was observed in females (40.6+/-15.3 years in 1997 vs 43.5+/-16.1 years in 2005, p<0.001).Our data indicate that, during a recent 9-year period, the age of onset of adult-onset asthma appears to be increasing in females, most likely because the numbers of female asthmatics who smoke, have a high total serum IgE level (IgE >or=300 IU/ml), have a high mite-specific IgE antibody score (RAST score >or=2), and have complications from or a past history of allergic rhinitis have declined.