Study objectives: To examine the association between SDB and subjective measures of daytime sleepiness, sleep quality, and sleep related quality of life in a large cohort of primarily community-dwelling older women, specifically considering the relative importance of sleep duration in mediating these associations.
Design: Cross-sectional. The functional outcome measures of interest were daytime sleepiness (using the Epworth Sleepiness Scale, ESS), sleep-related symptoms (Pittsburgh Sleep Quality Index, PSQI), and sleep related quality of life (Functional Outcomes of Sleep Questionnaire, FOSQ). ANOVA and regression analyses examined the association between SDB severity (measured by indices of breathing disturbances and overnight oxygen saturation) and sleep time (by actigraphy) and these outcome measures. Regression models were adjusted for age, body mass index (BMI), and a medical comorbidity index. We specifically explored whether associations with indices of SDB were mediated by sleep deprivation by adjusting models for actigraphy-determined average total sleep time (TST) during the night.
Setting: Community-based sample examined in home and outpatient settings.
Participants: 461 surviving older women from the multicenter Study of Osteoporotic Fractures were examined during Visit 8 from 2002-03. All participants underwent in-home overnight polysomnography for one night and wrist actigraphy for a minimum of 3 24-h periods and completed the above functional outcomes questionnaires.
Measurements and results: Participants were aged 82.9 +/- 3.5 (mean +/- SD) years, had BMI of 27.9 +/- 5.1 kg/m2, and had an apnea-hypopnea index (AHI) of 15.7 +/- 15.1. AHI and TST demonstrated a weak correlation (r = -0.15). ESS score individually demonstrated a modest association with AHI, oxygen desaturation, and TST. The association of ESS score and AHI--but not oxygen desaturation-was attenuated to some extent by adjustment for TST. PSQI and FOSQ scores were not associated with measures of SDB severity or TST.
Conclusions: After adjustment for TST, SDB severity in community-dwelling older women was not independently associated with self-reported daytime sleepiness, although there may be a modest association that is mediated through reduced TST. In older women, SDB severity was not associated with indices of sleep related symptoms or sleep related quality of life.