Objective: Circadian rest-activity rhythms (CARs) have been cross-sectionally associated with depressive symptoms, although no longitudinal research has examined whether CARs are a risk factor for developing depressive symptoms.
Methods: We examined associations of CARs (measured with actigraphy over a mean of 4.8 days) with depressive symptoms (measured with the Geriatric Depression Scale) among 2,892 community-dwelling older men (mean age: 76.2 ± 5.5 years) from the MrOS Sleep Study who were without cognitive impairment. Among 2,124 men with minimal (0-2) symptoms at baseline, we assessed associations between CAR parameters and increases to mild (3-5) or clinically significant (≥6) symptoms after an average of 1.2 (±0.32) years.
Results: Cross-sectional associations between rhythm height parameters were independent of chronic diseases, lifestyle, sleep, and self-reported physical activity covariates. For example, men in the lowest mesor quartile had twice the adjusted odds (adjusted odds ratio [AOR]: 2.04, 95% confidence interval [CI]: 1.36-3.04, p = 0.0005) of having prevalent clinically significant symptoms (compared to minimal). Longitudinally, low CAR robustness (being in the lowest quartile of the pseudo-F statistic) was independently associated with increasing odds of developing symptoms (i.e., AOR for having clinically significant depressive symptoms at follow-up = 2.58, 95% CI: 1.11-5.99, p = 0.03).
Conclusion: CAR disturbances are indicative of depressive symptomology. Low CAR robustness may independently contribute to the risk of worsening depression symptomology.
Keywords: Aging; circadian rest-activity rhythm (CAR); depression; epidemiology.
Copyright © 2015 American Association for Geriatric Psychiatry. Published by Elsevier Inc. All rights reserved.