title: Depressive symptoms and circadian activity rhythm disturbances in community-dwelling older women.
abstract: OBJECTIVE
  Aging is associated with changes in circadian rhythms. Current evidence supports a role for circadian rhythms in the pathophysiology of depression. However, little is known about the relationship between depressive symptoms and circadian activity rhythms in older adults. We examined this association in community-dwelling older women.
  
  
  METHODS
  We performed a cross-sectional analysis of 3,020 women (mean age: 83.55 ± 3.79 years) enrolled in the Study of Osteoporotic Fractures. Depressive symptoms were assessed with the Geriatric Depression Scale categorizing participants as "normal" (0-2; referent group, N = 1,961), "some depressive symptoms" (3-5, N = 704), or "depressed" (≥6, N = 355). Circadian activity rhythm variables were measured using wrist actigraphy.
  
  
  RESULTS
  In age-adjusted and Study of Osteoporotic Fractures site-adjusted models, greater levels of depressive symptoms were associated with decreased amplitude (height; df = 3,014, t = -11.31, p for linear trend <0.001), pseudo F-statistic (robustness; df = 3,014, t = -8.07, p for linear trend <0.001), and mesor (mean modeled activity; df = 3014, t = -10.36, p for linear trend <0.001) of circadian activity rhythms. Greater levels of depressive symptoms were also associated with increased odds of being in the lowest quartile for amplitude (df = 1, χ(2) = 9240, p for linear trend <0.001), pseudo F-statistic (df = 1, χ(2) = 49.73, p for linear trend <0.001), and mesor (df = 1, χ(2) = 81.12, p for linear trend <0.001). These associations remained significant in multivariate models. Post-hoc analyses comparing mean amplitude, mesor, and pseudo F-statistic values pair-wise between depression-level groups revealed significant differences between women with "some depressive symptoms" and the "normal" group.
  
  
  CONCLUSIONS
  These data suggest a graded association between greater levels of depressive symptoms and more desynchronization of circadian activity rhythms in community-dwelling older women. This association was observed even for women endorsing subthreshold levels of depressive symptoms.
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA.
authors.forename: Jeanne E
authors.initials: JE
authors.lastname: Maglione
authors.affiliation: Department of Psychiatry, University of California, San Diego, La Jolla, CA; Department of Medicine, University of California, San Diego, La Jolla, CA.
authors.forename: Sonia
authors.initials: S
authors.lastname: Ancoli-Israel
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco, CA.
authors.forename: Katherine W
authors.initials: KW
authors.lastname: Peters
authors.affiliation: Division of Epidemiology & Community Health, University of Minnesota, Minneapolis, MN.
authors.forename: Misti L
authors.initials: ML
authors.lastname: Paudel
authors.affiliation: Departments of Psychiatry, Neurology, and Epidemiology, University of California, San Francisco, CA.
authors.forename: Kristine
authors.initials: K
authors.lastname: Yaffe
authors.affiliation: Division of Epidemiology & Community Health, University of Minnesota, Minneapolis, MN; Department of Medicine, University of Minnesota, Minneapolis, MN; Center for Chronic Disease Outcomes Research, Veterans Affairs Medical Center, Minneapolis, MN.
authors.forename: Kristine E
authors.initials: KE
authors.lastname: Ensrud
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco, CA.
authors.forename: Greg J
authors.initials: GJ
authors.lastname: Tranah
authors.affiliation: California Pacific Medical Center Research Institute, San Francisco, CA. Electronic address: kstone@sfcc-cpmc.net.
authors.forename: Katie L
authors.initials: KL
authors.lastname: Stone
mesh_terms: D056044:Actigraphy; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology / Q000523:psychology*; D021081:Chronobiology Disorders / Q000453:epidemiology* / Q000523:psychology; D002940:Circadian Rhythm; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology* / Q000523:psychology; D005260:Female; D006801:Humans; D016014:Linear Models; D015999:Multivariate Analysis; D012307:Risk Factors
keywords: Depression; actigraphy; activity rhythms; circadian rhythms; older women; subthreshold depression