Previous research indicated that the use of exogenous female sex hormones is linked with the development of asthma; however, the question of whether the influence is protective or harmful remains uncertain.
In a recent publication in the Journal of Allergy and Clinical Immunology: In Practice, researchers employed a register-based, exposure-matched cohort study to explore the correlation between the initiation of hormonal contraceptive (HC) treatment and the development of asthma.
The study was reported according to the STrengthening the Reporting of OBservational studies in Epidemiology (STROBE) guidelines. The study population was comprised of women without asthma who initiated HC treatment of any type between age 10 and 40 years. Women exposed to HCs were subsequently matched with five women without asthma who had not yet initiated HC treatment.
The researchers defined new asthma “as two redeemed prescriptions of inhaled corticosteroids (ICS) within 2 years without previous filled prescriptions, or by registration of an ICD-10 code of J45 from an admission or a visit to an outpatient clinic without previous filled prescriptions.”
For women diagnosed by filled prescriptions, the date for asthma onset was the date of filling the second prescription, and women with prescriptions of ICS prior to the index date or an ICD-10 code indicating asthma were excluded from the study.
A total of 184,046 women with an average age of 15.5 years were included, of which 30,669 initiated HC treatment and 153,377 did not. The researchers discovered that the initiation of HCs was associated with an increased hazard ratio (HR) of developing new asthma by 1.78 (95% CI, 1.58-2.00, P <.001). Among users of HCs, the cumulative risk of new asthma was 2.7% after 3 years compared with 1.5% in nonusers. In the different subtypes of HCs, second- and third-generation contraceptives were linked with significant associations (second-generation HR 1.76; 95% CI, 1.52-2.03; P <.001; third-generation HR 1.62; 95% CI, 1.23-2.12; P <.001). The authors noted that the correlation with augmented incidence was only observed in women aged younger than 18 years.
Based on their findings, the authors wrote, “In this large, population-based study, we found that initiation of exogenous female sex hormones was associated with an increased hazard of initiating asthma among women younger than 18 years. Further, the cumulative risk of initiating asthma treatment was significantly increased within the first three years. Second- and third-generation HC pills carried the most statistically significant association with new-onset asthma, which were also the most used types of HC. Lastly, we also found that progestin-only oral pills were significantly associated with the development of new asthma.”
The authors concluded, “In this study, first-time users of HCs had an increased incidence of asthma compared with non-users. Reports of any airway symptoms following the initiation of HCs should lead to a clinical evaluation of whether the perceived symptoms could be the onset of asthma or a manifestation of asthma symptoms.”
Lastly, the authors noted that further studies are necessary to clinically and prospectively assess whether HCs generate harmful reactions in the airways.
The content contained in this article is for informational purposes only. The content is not intended to be a substitute for professional advice. Reliance on any information provided in this article is solely at your own risk.