title: Circadian rest-activity rhythms predict future increases in depressive symptoms among community-dwelling older men.
abstract: 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).
  
  
  CONCLUSIONS
  CAR disturbances are indicative of depressive symptomology. Low CAR robustness may independently contribute to the risk of worsening depression symptomology.
authors: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA.
authors: Stephen F
authors: SF
authors: Smagula
authors: Departments of Psychiatry and Medicine, University of California San Diego, San Diego, CA; VA Center of Excellence for Stress and Mental Health (CESAMH), San Diego, CA.
authors: Sonia
authors: S
authors: Ancoli-Israel
authors: Research Institute, California Pacific Medical Center, San Francisco, CA.
authors: Terri
authors: T
authors: Blackwell
authors: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA.
authors: Robert
authors: R
authors: Boudreau
authors: Department of Medicine, Stanford Prevention Research Center, Stanford, CA.
authors: Marcia L
authors: ML
authors: Stefanick
authors: Division of Epidemiology & Community Health, University of Minnesota, Minneapolis, MN.
authors: Misti L
authors: ML
authors: Paudel
authors: Research Institute, California Pacific Medical Center, San Francisco, CA.
authors: Katie L
authors: KL
authors: Stone
authors: Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA. Electronic address: jcauley@edc.pitt.edu.
authors: Jane A
authors: JA
authors: Cauley
mesh_terms: D056044:Actigraphy / Q000379:methods; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology / Q000523:psychology; D021081:Chronobiology Disorders / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology / Q000523:psychology; D015897:Comorbidity; D003863:Depression / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology; D005500:Follow-Up Studies; D015577:Geriatric Assessment / Q000379:methods; D006801:Humans; D057187:Independent Living / Q000523:psychology; D008019:Life Style; D008297:Male; D009043:Motor Activity; D011569:Psychiatric Status Rating Scales; D012307:Risk Factors; D012890:Sleep; D014481:United States / Q000453:epidemiology
keywords: Aging; circadian rest-activity rhythm (CAR); depression; epidemiology