The association of asthma, atopy and lung function with hormone replacement therapy and surgical cessation of menstruation in a population-based sample of English women

Sex Plays a Multifaceted Role in Asthma Pathogenesis

Sex is considered an important risk factor for asthma onset and exacerbation. The prevalence of asthma is higher in boys than in girls during childhood, which shows a reverse trend after puberty—it becomes higher in adult females than in adult males. In addition, asthma severity, characterized by the rate of hospitalization and relapse after discharge from the emergency department, is higher in female patients. Basic research indicates that female sex hormones enhance type 2 adaptive immune responses, and male sex hormones negatively regulate type 2 innate immune responses. However, whether hormone replacement therapy in postmenopausal women increases the risk of current asthma and asthma onset remains controversial in clinical settings. Recently, sex has also been shown to influence the pathophysiology of asthma in its relationship with genetic or other environmental factors, which modulate asthmatic immune responses in the airway mucosa. In this narrative review, we highlight the role of sex in the continuity of the asthmatic immune response from sensing allergens to Th2 cell activation based on our own data. In addition, we elucidate the interactive role of sex with genetic or environmental factors in asthma exacerbation in women.

Population-based study of the association between asthma and exogenous female sex hormone use

OBJECTIVES

Several studies have suggested the influence of exogenous hormones on asthma, but the results are still conflicting. Moreover, there has been little associated research on Asian population. This study aimed to assess the association between use of exogenous female sex hormones and asthma in Korean women.

DESIGN

Korea National Health and Nutrition Examination Survey (KNHANES) is a nationwide programme to assess national health and nutritional status in Korea. A population-based study was conducted to analyse the relationship between self-reported asthma and exogenous hormones using the KNHANES between 2007 and 2012.

PARTICIPANTS

The study sample included 6874 premenopausal and 4912 postmenopausal women aged 30-65.

OUTCOME MEASURES

KNHANES data comprised health interviews and physical examinations. Questionnaires regarding asthma, reproductive factors and exogenous hormones were included.

RESULTS

Among postmenopausal women, 3.4% reported doctor-diagnosed asthma. Hormone replacement therapy (HRT) was associated with increased odds of doctor-diagnosed asthma (OR 1.56; 95% CI 1.04 to 2.35), while the association between HRT and wheeze in the last 1 year was not significant (OR 1.37; 95% CI 0.95 to 1.96). In premenopausal women, the prevalence of asthma was 2.3%. Use of oral contraceptives (OCs) was associated with an increased odds of doctor-diagnosed asthma (OR 1.67; 95% CI 1.01 to 2.76) and wheeze in the last 1 year (OR 1.88; 95% CI 1.31 to 2.69). These associations were dominant among non-obese women (body mass index <25 kg/m²; OR 2.36; 95% CI 1.34 to 4.17 for asthma and OR 2.15; 95% CI 1.43 to 3.23 for wheeze).

CONCLUSIONS

HRT and OCs were associated with increased asthma in postmenopausal and premenopausal women, respectively. The association between OC use and asthma was strong in non-obese premenopausal women.

Association between reproductive lifespan and lung function among postmenopausal women

Correspondence to: Hye Yun Park, MD, PhD. Division of Pulmonary and Critical Care Medicine, Department of Medicine, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, South Korea. Email: hyeyunpark@skku.edu; Juhee Cho, PhD. Department of Clinical Research Design and Evaluation, SAIHST, Sungkyunkwan University, 81 Irwon-ro, Gangnam-gu, Seoul, 06351, South Korea. Email: Jcho@skku.edu.

Exogenous sex steroid hormones and asthma in females: protocol for a population-based retrospective cohort study using a UK primary care database

INTRODUCTION

Female sex steroid hormones have been implicated in sex-related differences in the development and clinical outcomes of asthma. The role of exogenous sex steroids, however, remains unclear. Our recent systematic review highlighted the lack of high-quality population-based studies investigating this subject. We aim to investigate whether the use of hormonal contraception and hormone replacement therapy (HRT), subtypes and route of administration are associated with asthma onset and clinical outcomes in reproductive age and perimenopausal/postmenopausal females.

METHODS AND ANALYSIS

Using the Optimum Patient Care Research Database (OPCRD), a national primary care database in the UK, we will construct a retrospective longitudinal cohort of reproductive age (16-45 years) and perimenopausal/postmenopausal (46-70 years) females. We will estimate the risk of new-onset asthma using Cox regression and multilevel modelling for repeated asthma outcomes, such as asthma attacks. We will adjust for confounding factors in all analyses. We will evaluate interactions between the use of exogenous sex hormones and body mass index and smoking by calculating the relative excess risk due to interaction and the attributable proportion due to interaction. With 90% power, we need 23 700 reproductive age females to detect a 20% reduction (risk ratio 0.8) in asthma attacks for use of any hormonal contraception and 6000 perimenopausal/postmenopausal females to detect a 40% (risk ratio 1.40) increased risk of asthma attacks for use of any HRT.

ETHICS AND DISSEMINATION

We have obtained approval (ADEPT1317) from the Anonymised Data Ethics and Protocol Transparency Committee which grants project-specific ethics approvals for the use of OPCRD data. Optimum Patient Care has an existing NHS Health Research Authority ethics approval for the use of OPCRD data for research (15/EM/150). We will present our findings at national and international scientific meetings and publish the results in international peer-reviewed journals.

TRIAL REGISTRATION NUMBER

EUPAS22967.

Asthma is Different in Women

Gender differences in asthma incidence, prevalence and severity have been reported worldwide. After puberty, asthma becomes more prevalent and severe in women, and is highest in women with early menarche or with multiple gestations, suggesting a role for sex hormones in asthma genesis. However, the impact of sex hormones on the pathophysiology of asthma is confounded by and difficult to differentiate from age, obesity, atopy, and other gender associated environmental exposures. There are also gender discrepancies in the perception of asthma symptoms. Understanding gender differences in asthma is important to provide effective education and personalized management plans for asthmatics across the lifecourse.

Hormonal contraceptives and asthma in women of reproductive age: analysis of data from serial national Scottish Health Surveys

OBJECTIVES

Sex steroid hormones may explain known gender-related variations in asthma prevalence and clinical manifestation. We investigated the relationship between use of hormonal contraceptives and asthma in women, and assessed evidence of biological interaction between use of hormonal contraceptives and body mass index in this relationship.

DESIGN

Population-based analysis using data from serial (i.e. 2003, 2008 and 2010) Scottish Health Surveys.

SETTING

Random samples of the Scottish general population.

PARTICIPANTS

A total of 3257 non-pregnant, 16-45-year-old women.

EXPOSURE

Current use of hormonal contraceptives.

MAIN OUTCOME MEASURES

Self-reported current physician-diagnosed asthma, current wheezing symptoms, wheezing attacks and treatment for asthma or wheeze.

RESULTS

Women comprising 30.9% (95% confidence interval 29.3-32.5) were currently using any hormonal contraceptive and current physician-diagnosed asthma was present in 6.5% (95% confidence interval 5.7-7.4). Use of any hormonal contraceptive was associated with reduced risk of current physician-diagnosed asthma (odds ratio 0.68; 95% confidence interval 0.47-0.98) and receiving ≥3 asthma care episodes (odds ratio 0.45; 95% confidence interval 0.25-0.82), but the evidence was equivocal for wheezing attacks. Use of hormonal contraceptives among overweight or obese women was non-statistically significantly associated with asthma, but there was 42-135% increased risk in overweight and obese non-contraceptive using women.

CONCLUSIONS

Use of hormonal contraceptives may reduce asthma exacerbations and number of care episodes. Overweight and obese non-contraceptive-using women may be at increased risk of asthma. Prospective studies are now needed to confirm these findings. Both oestrogen and progesterone may stimulate smooth airway muscle function and inhibit the activities of TH2 responses. Future studies should investigate these underlying mechanisms.

Parity, age at first birth, and risk of death from asthma: evidence from a cohort in taiwan

This study was undertaken to examine whether there is an association between age at first birth and parity and risk of asthma death. The study cohort consisted of 1,292,462 women in Taiwan who had a first live birth between 1 January 1978 and 31 December 1987. We tracked each woman from the date of their first childbirth to 31 December 2009, and their vital status was ascertained by linking records with the computerized mortality database. Cox proportional hazard regression models were used to estimate hazard ratios of death from asthma associated with parity and age at first birth. A trend of increasing risk of asthma death was seen with increasing age at first birth. The adjusted hazard ratio was 0.75 (95% confidence interval (CI) = 0.53–1.08) among women with two live births and 0.53 (95% CI = 0.36–0.78) among those with three or more births, compared with women who had one live birth. There was a significant decreasing trend in adjusted hazard ratios of asthma death with increasing parity. This study is the first to provide evidences to support an association between reproductive factors (parity and early age at first birth) and the risk of asthma death.

Postmenopausal hormone therapy and asthma onset in the E3N cohort

BACKGROUND

Epidemiological studies have suggested that female hormones might play a role in asthma and that menopausal hormone therapy (MHT or hormone replacement therapy (HRT)) might increase the risk of asthma in postmenopausal women. The only prospective study addressing this issue reports an increase in the risk of developing asthma which was similar for oestrogen alone and oestrogen/progestagen treatment.

METHODS

The association between the use of different types of MHT and the risk of asthma onset in postmenopausal women was investigated prospectively from 1990 to 2002 by biennial questionnaires as part of the French E3N cohort study. Asthma onset was considered to be the time of medical diagnosis of asthma cases occurring during the follow-up of women who were asthma free at baseline. Cox proportional hazards models were used, adjusting for potential confounding factors.

RESULTS

Among 57 664 women free of asthma at menopause, 569 incident cases of asthma were identified during 495 448 years of follow-up. MHT was related to an increased risk of asthma onset (HR=1.20, 95% CI 0.98 to 1.46) among recent users. The increase in risk of asthma onset was only significant among women reporting the use of oestrogen alone (HR=1.54, 95% CI 1.13 to 2.09) particularly in never smokers (HR=1.80, 95% CI 1.15 to 2.80) and women reporting allergic disease prior to asthma onset (HR=1.86, 95% CI 1.18 to 2.93). A small increase in the risk of asthma onset associated with the use of oestrogen/progestagen was also observed in these subgroups.

CONCLUSION

Postmenopausal use of oestrogen alone was associated with an increased rate of newly diagnosed asthma in menopausal women.