Asthma, menopause and HRT
30 January, 2017:
Asthma is basically an inflammatory disease, sometimes associated with allergy. Several publications have addressed recently the potential association between menopause and asthma. The latest study examined the possibility that there is a link between menopause and new-onset asthma [1]: the Respiratory Health in Northern Europe study provided questionnaire data pertaining to respiratory and reproductive health at baseline (1999–2001) and follow-up (2010–2012). The study cohort included women aged 45–65 years at follow-up, without asthma at baseline, and not using exogenous hormones (n = 2322). Menopausal status was defined as non-menopausal, transitional, early postmenopausal, and late postmenopausal. Associations with asthma (defined by the use of asthma medication, having asthma attacks, or both) and respiratory symptoms scores were analyzed by using logistic (asthma) and negative binomial (respiratory symptoms) regressions, adjusting for age, body mass index, physical activity, smoking, education, and study center. The odds (OR) of new-onset asthma were increased in women who were transitional (OR 2.4; 95% CI 1.09–5.30), early postmenopausal (OR 2.1; 95% CI 1.06–4.20), and late postmenopausal (OR 3.4; 95% CI 1.31–9.05) at follow-up compared with non-menopausal women. The risk of respiratory symptoms increased in early postmenopausal and late postmenopausal women as well.
Comment
Epidemiological data show that asthma prevalence, severity, exacerbation rate, hospitalizations and mortality are higher among women than men overall [2]. The transition from childhood to adulthood is characterized by a higher odds ratio of persistence of wheezing and asthma worsening in females. A growing body of clinical and experimental evidence indicates that female sex hormones, particularly estrogen, have significant effects on normal airway function. These effects are very complex and are exerted at several levels, directly on airway reactivity or indirectly through regulation of the immune and inflammatory responses in the lung. Asthma presents as a heterogeneous disease: in typical Th2-type allergic asthma, interleukin (IL)-4 and IL-13 predominate, driving IgE production and recruitment of eosinophils into the lungs. Chronic Th2-inflammation in the lung results in structural changes and activation of multiple immune cell types, leading to a deterioration of lung function over time. Most immune cells express estrogen receptors (ER alpha and beta, or the membrane-bound G-protein-coupled ER) to varying degrees and can respond to the hormone. Together these receptors have demonstrated the capacity to regulate a spectrum of immune functions. Kesselman and Heller reviewed the current understanding of estrogen signaling in allergic inflammation and discussed how this signaling may contribute to sex differences in asthma and allergy [3].