title: The role of frailty in the association between depression and somatic comorbidity: results from baseline data of an ongoing prospective cohort study.
abstract: BACKGROUND
  Depression and physical frailty in older persons are both associated with somatic diseases, but are hardly examined in concert.
  
  
  OBJECTIVE
  To examine whether depression and physical frailty act independently and/or synergistically in their association with somatic diseases.
  
  
  METHODS
  Baseline data of an ongoing observational cohort study including depressed cases and non-depressed comparison subjects.
  
  
  METHODS
  Netherlands Study of Depression in Older persons (NESDO).
  
  
  METHODS
  378 depressed older persons confirmed by the Composite International Diagnostic Interview (CIDI), version 2.1, and 132 non-depressed comparison subjects.
  
  
  METHODS
  Multiple linear regression analyses adjusted for socio-demographic and life-style characteristics were conducted with the number of somatic diseases as the dependent variable and depression and physical frailty as independent variables. Physical frailty was defined as ≥3 of the following characteristics, slowness, low physical activity, weight loss, exhaustion, and weakness.
  
  
  RESULTS
  Depression and physical frailty did not interact in explaining variance in the number of somatic diseases (p=.57). Physical frailty, however, partly mediated the association between depression and somatic diseases, as the strength of this association decreased by over 10% when frailty was added to the model (B=0.47, p=.003, versus B=0.41, p=.01). The mediation effect was primarily driven by the frailty criterion exhaustion. Of the remaining frailty components, only slowness was associated with the number of somatic diseases; but this association was fully independent of depression.
  
  
  CONCLUSIONS
  Our results suggest that depression and physical frailty have common pathways towards somatic diseases, as well as unique pathways. As no high-risk group was identified (no significant interaction), mental health nurses should regularly monitor for physical frailty within their caseload of depressed patients.
authors.affiliation: Department of Psychiatry, University Medical Centre St. Radboud, Nijmegen, The Netherlands; Pro Persona, Nijmegen Mental Health Centre, The Netherlands. Electronic address: rose.collard@radboudumc.nl.
authors.forename: Rose M
authors.initials: RM
authors.lastname: Collard
authors.affiliation: University Center for Psychiatry and Interdisciplinary Center for Psychopathology of Emotion regulation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Matheus
authors.initials: M
authors.lastname: Arts
authors.affiliation: Department of Psychiatry, VU University Medical Center, Amsterdam, The Netherlands; EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, The Netherlands; GGZinGeest, Amsterdam, The Netherlands.
authors.forename: Hannie C
authors.initials: HC
authors.lastname: Comijs
authors.affiliation: Department of Psychiatry, University Medical Centre St. Radboud, Nijmegen, The Netherlands; GGNet, Department of Old-age Psychiatry, Apeldoorn/Zutphen, The Netherlands.
authors.forename: Paul
authors.initials: P
authors.lastname: Naarding
authors.affiliation: Department General Practice, University Medical Center Groningen, University of Groningen, The Netherlands; NIVEL, Netherlands Institute for Health Services Research, Utrecht, The Netherlands.
authors.forename: Peter F M
authors.initials: PF
authors.lastname: Verhaak
authors.affiliation: Department of Public Health and Primary Care, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: Margot W
authors.initials: MW
authors.lastname: de Waal
authors.affiliation: Department of Psychiatry, University Medical Centre St. Radboud, Nijmegen, The Netherlands; University Center for Psychiatry and Interdisciplinary Center for Psychopathology of Emotion regulation, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.
authors.forename: Richard C
authors.initials: RC
authors.lastname: Oude Voshaar
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D003866:Depressive Disorder / Q000150:complications*; D006801:Humans; D011446:Prospective Studies
keywords: Aged; Depression; Frailty; Netherlands Study of Depression in Older persons (NESDO); Somatic diseases