0348 Menopause, Hormone Replacement Therapy and Insomnia Phenotypes based on Objective Sleep Duration: The Penn State Adult Cohort

Abstract

Introduction: Previous studies showed a higher prevalence of sleep disordered breathing (SDB) in postmenopausal women, particularly those not taking hormone replacement therapy (HRT). This association has not been examined in insomnia using polysomnography (PSG) to identify insomnia phenotypes based on objective sleep duration and control for SDB. Methods: Data from the Penn State Adult Cohort (N=1741) was used in this study (52.2% women, 48.8 ± 13.6 years). Women were classified as premenopausal or postmenopausal taking or not taking HRT. We defined the presence of chronic insomnia as a complaint of insomnia lasting at least 1 year and objective short sleep duration as < 6-h based on a 1-night, 8-hours, in-lab PSG. SDB was defined as an apnea hypopnea index ≥ 5. Results: The prevalence of chronic insomnia with short sleep duration was significantly higher in postmenopausal women taking HRT (12.9%) as compared to premenopausal (3.2%, p<0.001) or postmenopausal women not taking HRT (6.1%, p=0.020), while the prevalence of chronic insomnia with normal sleep duration was not significantly different across groups (2.5%, 5.7% and 5.0%, respectively). Differences in the prevalence of chronic insomnia with normal or short sleep duration across middle-aged and older men were marginal to non-significant (p>;0.06). These associations did not change when subjects with SDB were excluded from the analyses. Conclusion: The novel data in this study indicate that postmenopausal women taking HRT are more likely to have insomnia with objective short sleep duration, a more biological severe phenotype of the disorder associated with increased cardiovascular risk. These data also suggest that this insomnia subtype may be associated with more severe postmenopausal symptoms that may have required administration of HRT. Future studies should examine the potential contribution of hot flashes/vasomotor symptoms as well as the potential role for this insomnia phenotype in the association of HRT with adverse cardiovascular outcomes.