Hormonal contraceptives and onset of asthma in reproductive-age women: population-based cohort study

Bright Nwaru, Rebecca Pillinger, Holly Tibble, Syed Ahmar Shah, Dermot Ryan, Hilary Critchley, David Price, Catherine M Hawrylowicz, Colin Simpson, Ireneous Soyiri, Francis Appiagyei, Aziz Sheikh

Research output: Contribution to journalArticlepeer-review


Background: Despite well-described sex differences in asthma incidence, there remains uncertainty about the role of female sex hormones in the development of asthma.

Objective: To investigate whether hormonal contraceptive use, its subtypes, and duration of use were associated with new-onset asthma in reproductive-age women.

Methods: Using the Optimum Patient Care Research Database, a UK national primary care database, we constructed an open cohort of 16-45-year-old women (N=564,896) followed for up to 17 years (i.e. 1/1/2000–31/12/2016). We fitted multilevel Cox regression models to analyze the data.

Results: At baseline, 26% of women were using any hormonal contraceptives. During follow-up (3,597,146-person-years), 25,288 women developed asthma, an incidence rate of 7.0 (95%CI 6.9-7.1) per-1,000-person-years. Compared to non-use, previous use of any hormonal contraceptives (hazard ratio [HR] 0.70; 95%CI 0.68-0.72), combined (HR 0.70; 95%CI 0.68-0.72), and progestogen-only therapy (HR 0.70; 95%CI 0.67-0.74) were associated with reduced risk of new-onset asthma. For current use, the estimates were: any (HR 0.63; 95%CI 0.61-0.65), combined (HR 0.65; 95%CI 0.62-0.67), and progestogen-only therapy (HR 0.59; 95%CI 0.56-0.62). Longer duration of use (1-2 years: HR 0.83; 95%CI 0.81-0.86; 3-4 years: HR 0.64; 95%CI 0.61-0.67; 5+ years: HR 0.46; 95%CI 0.44-0.49) was associated with lower risk of asthma onset than non-use.

Conclusion: Hormonal contraceptive use was associated with reduced risk of new-onset asthma in women of reproductive age. Mechanistic investigations to uncover the biological processes for these observations are required. Clinical trials investigating the safety and effectiveness of hormonal contraceptives for primary prevention of asthma will be helpful to confirm these results.

Clinical Implication: Although there are so far no randomized clinical trial directly testing the hypothesis, the current study shows that hormonal contraceptives may serve as a primary prevention strategy for asthma in reproductive-age women.
Original languageEnglish
JournalJournal of Allergy and Clinical Immunology
Early online date15 Apr 2020
Publication statusE-pub ahead of print - 15 Apr 2020


Dive into the research topics of 'Hormonal contraceptives and onset of asthma in reproductive-age women: population-based cohort study'. Together they form a unique fingerprint.

Cite this