Helicobacter pylori infection increases the risk of adult-onset asthma: a nationwide cohort study.

Helicobacter pylori infection (HPI) appears to reduce risk of childhood-onset asthma, but the relationship between HPI and adult-onset asthma is inconclusive. This study explored the potential association between HPI and risk of adult-onset asthma. We conducted a national insurance retrospective cohort study using the longitudinal health insurance database (LHID 2000) in Taiwan. We enrolled the HPI group consisting of 1664 patients with HPI diagnosis between 2000 and 2007, and the non-HPI group consisting of 6,656 age- and sex-matched subjects without HPI. All study participants had been followed up from index date to the diagnostic date of asthma, withdrawal from the National Health Insurance program, or the end of 2011, which came first. We analyzed risk of adult-onset asthma with respect to sex, age, and comorbidities by using Cox models. Cigarette smoking status, which could not be obtained from the program, was adjusted indirectly by considering chronic obstructive pulmonary diseases in our statistical models because the disease is related to heavy smoking. After adjustment for sex, age, and comorbidities, HPI was significantly associated with an increased 1.38-fold risk of adult-onset asthma. Moreover, among people without comorbidities, the 1.85-fold risk of adult-onset asthma remained higher for the HPI population compared with the non-HPI population. In this study, patients with HPI exhibited a significantly higher risk of adult-onset asthma than did the subjects without HPI.