Impaired respiratory function in women with PCOS compared to matched controls from a population-based study

CONTEXT: Increased prevalence of asthma has been reported from epidemiological studies in women with polycystic ovary syndrome (PCOS). OBJECTIVE: To investigate respiratory function in women with PCOS compared with controls in a clinical setting. DESIGN: An 8-year clinical follow-up study including self-reported asthma diagnoses and spirometry of women with PCOS randomized to metformin or placebo during pregnancy in the original studies (the Pilot and the PregMet-study), compared with matched controls from a population-based cohort study (The HUNT Study). SETTING: Secondary and tertiary care centers. PARTICIPANTS: A total of 145 women with PCOS (54% of original cohort) were matched 1:3 to controls, on gender, age, and smoking-status. MAIN OUTCOMES AND MEASURES: Self-reported doctor-diagnosed asthma (DDA), percentage of predicted forced expiratory volume in the first second of expiration (FEV1 % predicted), percentage of predicted forced vital capacity (FVC % predicted). RESULTS: Women with PCOS reported more DDA compared with controls (19% vs 9%; P < 0.01). Spirometry indicated a combined obstructive (FEV1 % predicted, 93.7 vs 102.0; P < 0.01) and restrictive (FVC % predicted, 94.5 vs 103.7; P < 0.01) respiratory impairment in PCOS compared with controls. Metformin in pregnancy did not affect respiratory function at follow-up. CONCLUSION: Women with PCOS reported higher prevalence of DDA compared with controls matched for age and smoking status. In addition, respiratory function was decreased, with both obstructive and restrictive components. Further insight to the underlying pathogenesis of these observations is needed. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov: The PregMet study: NCT00159536. The Pilot study: NCT03259919.