Age-Related Differences in Sleep-Wake Symptoms of Adults Undergoing Polysomnography

Abstract

Objectives: To evaluate age-related differences in sleep-wake symptoms.

Design: Cross-sectional.

Setting: Technologist-attended, laboratory-based polysomnography (PSG).

Participants: Community-dwelling adults aged 20 to 89 (N = 201): 52 aged 18 to 39, 72 aged 40 to 59, and 77 aged 60 and older.

Measurements: Medical burden (Charlson Comorbidity Index, medications, health status), PSG-defined sleep disorders (sleep-disordered breathing (SDB), sleep-associated hypoxemia, periodic limb movements in sleep (PLMS)), sleep-wake symptoms (Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), fatigue (Facit-F Scale)).

Results: Medical burden increased significantly with age (Charlson Comorbidity Index and number of medications, P < .001; health status, P = .005). Severity of sleep disorders also increased significantly with age (SDB and hypoxemia, P < .001; PLMS, P = .008). Conversely, sleep-wake symptoms decreased with age (daytime drowsiness (ESS ≥ 10), P = .02; insomnia (ISI ≥ 8), P = .04; fatigue, P < .001). In adjusted models, a 1-year increase in age was significantly associated with a 4% decrease in the odds of having daytime drowsiness (odds ratio (OR) = 0.96, 95% confidence interval (CI) = 0.93-0.98). Similarly, but only in those with mild SDB, a 1-year increase in age was significantly associated with a 5% decrease in the odds of having insomnia (OR = 0.95, 95% CI = 0.92-0.99).

Conclusion: Older age was characterized by less-severe sleep-wake symptoms (daytime drowsiness, insomnia, fatigue), despite an age-related increase in disease severity (medical burden, sleep disorders). Because the increase in disease severity included well-established risk factors for having sleep-wake symptoms, the age-related decrease in sleep-wake symptoms may reflect a decrease in symptom awareness.

Keywords: driving capacity; periodic limb movements; sleep-disordered breathing; sleep-wake symptoms.