title: Depressive symptoms, physical inactivity and risk of cardiovascular mortality in older adults: the Cardiovascular Health Study.
abstract: BACKGROUND
  Depressed older individuals have a higher mortality than older persons without depression. Depression is associated with physical inactivity, and low levels of physical activity have been shown in some cohorts to be a partial mediator of the relationship between depression and cardiovascular events and mortality.
  
  
  METHODS
  A cohort of 5888 individuals (mean 72.8 ± 5.6 years, 58% female, 16% African-American) from four US communities was followed for an average of 10.3 years. Self-reported depressive symptoms (10-item Center for Epidemiological Studies Depression Scale) were assessed annually and self-reported physical activity was assessed at baseline and at 3 and 7 years. To estimate how much of the increased risk of cardiovascular mortality associated with depressive symptoms was due to physical inactivity, Cox regression with time-varying covariates was used to determine the percentage change in the log HR of depressive symptoms for cardiovascular mortality after adding physical activity variables.
  
  
  RESULTS
  At baseline, 20% of participants scored above the cut-off for depressive symptoms. There were 2915 deaths (49.8%), of which 1176 (20.1%) were from cardiovascular causes. Depressive symptoms and physical inactivity each independently increased the risk of cardiovascular mortality and were strongly associated with each other (all p < 0.001). Individuals with both depressive symptoms and physical inactivity had greater cardiovascular mortality than those with either individually (p < 0.001, log rank test). Physical inactivity reduced the log HR of depressive symptoms for cardiovascular mortality by 26% after adjustment. This was similar for persons with (25%) and without (23%) established coronary heart disease.
  
  
  CONCLUSIONS
  Physical inactivity accounted for a significant proportion of the risk of cardiovascular mortality due to depressive symptoms in older adults, regardless of coronary heart disease status.
authors.affiliation: Johns Hopkins University School of Medicine, Department of Medicine, B-1-North, Johns Hopkins Bayview Medical Center, Baltimore, MD 21224-2780, USA.
authors.forename: Sithu
authors.initials: S
authors.lastname: Win
authors.forename: Kapil
authors.initials: K
authors.lastname: Parakh
authors.forename: Chete M
authors.initials: CM
authors.lastname: Eze-Nliam
authors.forename: John S
authors.initials: JS
authors.lastname: Gottdiener
authors.forename: Willem J
authors.initials: WJ
authors.lastname: Kop
authors.forename: Roy C
authors.initials: RC
authors.lastname: Ziegelstein
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D002318:Cardiovascular Diseases / Q000209:etiology* / Q000401:mortality; D003863:Depression / Q000150:complications* / Q000401:mortality / Q000503:physiopathology; D004812:Epidemiologic Methods; D005260:Female; D006801:Humans; D008297:Male; D009043:Motor Activity; D011569:Psychiatric Status Rating Scales; D014481:United States / Q000453:epidemiology