Li, S.

Abstract RATIONALE: Significant sex differences exist in the prevalence and severity of asthma across the lifespan. Asthma is more prevalent and severe in pubescent boys compared to girls but worse in girls and women after puberty. The transition to menopause brings significant reductions in estrogen and progesterone levels. In this study, we test the hypothesis that the effect of menopause on asthma prevalence and outcomes is modified by the use of female sex hormones. METHODS: We used data from nine two-year cycles (1999-2000 to 2015-2016) from NHANES to determine the association between menopause and asthma outcomes. We defined severe asthma based on GINA treatment classes 4&5. We used analytic sample weights to compute national estimates according to NHANES guidelines. Adult (age >18 years) women were considered to be menopaused if (1) they reported to be menopaused during the NHANES survey, (2) they had bilateral oophorectomy, or (3) they were ≥52 years. Weighted logistic regression analyses were used to adjust for age, race, body mass index (BMI), smoking, blood eosinophil count, female hormone therapy, and oral contraceptives. Analyses were performed using the SURVEY package in R. RESULTS: The cohorts’ clinical characteristics are listed in table 1. Compared to pre-menopause (weighted n=60,394,897), menopause (weighted n=52,364,594) was associated with higher rates of active asthma (9.2 vs. 8.9%, p=0.004) and severe asthma (5% vs. 1.8%, p<0.001), but not lifetime asthma (15.1 vs. 16.3%, p=0.063). Notably, postmenopausal women had higher BMIs (weighted median [IQR]: 28.1 [24.2-33.1] vs. 26.1 [22.6-32.1], p<0.001), longer asthma durations (weighted median [IQR]: 20.0 [7.0-41.0] vs. 15.0 [8.0-24.0], p<0.001), and lower lung functions (p<0.001) (table 1). Adjusted analysis did not show significant associations between menopause and lifetime asthma (adjusted OR, 1.074; 95% CI, 0.901-1.280), active asthma (adjusted OR, 1.072; 95% CI, 0.865-1.328), or severe asthma (adjusted OR, 1.369; 95% CI, 0.958-1.954). Interestingly, a history of female hormone therapy and oral contraceptives use was associated with a higher risk of lifetime asthma (adjusted OR, 1.191; 95% CI, 1.031-1.375 and adjusted OR, 1.287; 95% CI, 1.169-1.417 respectively). Among women with active asthma, menopause was not associated with non-severe exacerbations (adjusted OR, 1.335; 95% CI, 0.883-2.021) or with severe exacerbations requiring ER visits (adjusted OR, 1.416; 95% CI, 0.818-2.451). Conclusion: The increased prevalence of active asthma and severe asthma among menopausal women can largely be attributed to age-related changes, comorbidities, and hormone therapy use rather than menopause alone.