Elevated Testosterone Is Associated with Decreased Likelihood of Current Asthma Regardless of Sex

BACKGROUND: Asthma prevalence decreases postpuberty in males. Testosterone inhibits airway smooth muscle contraction and attenuates type 2 inflammation. OBJECTIVE: To investigate the relationship between serum testosterone and current asthma prevalence and lung function in a nationally representative data set. METHODS: Serum testosterone and self-reported physician-diagnosed current asthma data were obtained from 7584 participants aged 6 to 80 years from the cross-sectional 2011-2012 National Health and Nutrition Examination Survey. We used logistic regression to test associations between testosterone and current asthma, adjusting for demographic characteristics and stratifying by sex and age; linear regression to evaluate correlations between testosterone and lung function among patients with asthma; and interaction terms to test for effect modification by blood eosinophils and fractional exhaled nitric oxide. RESULTS: Serum testosterone inversely associated with odds of current asthma in both men and women, but this association was nonlinear. Similar protective effect sizes were observed for both sexes after log(2)-transformation of serum testosterone. For every 1-unit increase in log(2) testosterone, the odds of current asthma decreased by 11% in men and 10% in women, although the association was statistically significant in women only among those 12 years or older after multiple imputation. Serum testosterone did not associate with current asthma prevalence among those younger than 12 years. Testosterone associated with increases in FEV1 in participants with asthma of both sexes. Neither blood eosinophils nor fractional exhaled nitric oxide modified the association between testosterone and current asthma. CONCLUSIONS: Serum testosterone inversely associates with current asthma prevalence regardless of sex and correlates with better lung function in a nationally representative database. Androgen therapy for asthma should be further investigated. (C) 2020 American Academy of Allergy, Asthma & Immunology.