title: Sitting-time, physical activity, and depressive symptoms in mid-aged women.
abstract: BACKGROUND
  Associations of sitting-time and physical activity with depression are unclear.
  
  
  OBJECTIVE
  To examine concurrent and prospective associations between both sitting-time and physical activity with prevalent depressive symptoms in mid-aged Australian women.
  
  
  METHODS
  Data were from 8950 women, aged 50-55 years in 2001, who completed mail surveys in 2001, 2004, 2007, and 2010. Depressive symptoms were assessed using the Center for Epidemiological Studies Depression questionnaire. Associations between sitting-time (≤ 4 hours/day, >4-7 hours/day, >7 hours/day) and physical activity (none, some, meeting guidelines) with depressive symptoms (symptoms/no symptoms) were examined in 2011 in concurrent and lagged mixed-effect logistic modeling. Both main effects and interaction models were developed.
  
  
  RESULTS
  In main effects modeling, women who sat >7 hours/day (OR=1.47, 95% CI=1.29, 1.67) and women who did no physical activity (OR=1.99, 95% CI=1.75, 2.27) were more likely to have depressive symptoms than women who sat ≤ 4 hours/day and who met physical activity guidelines, respectively. In interaction modeling, the likelihood of depressive symptoms in women who sat >7 hours/day and did no physical activity was triple that of women who sat ≤ 4 hours/day and met physical activity guidelines (OR 2.96, 95% CI=2.37, 3.69). In prospective main effects and interaction modeling, sitting-time was not associated with depressive symptoms, but women who did no physical activity were more likely than those who met physical activity guidelines to have future depressive symptoms (OR=1.26, 95% CI=1.08, 1.47).
  
  
  CONCLUSIONS
  Increasing physical activity to a level commensurate with guidelines can alleviate current depression symptoms and prevent future symptoms in mid-aged women. Reducing sitting-time may ameliorate current symptoms.
authors: Institute of Sport, Exercise and Active Living, Victoria University, Melbourne, Victoria, Australia. jannique.vanuffelen@vu.edu.au
authors: Jannique G Z
authors: JG
authors: van Uffelen
authors: Yolanda R
authors: YR
authors: van Gellecum
authors: Nicola W
authors: NW
authors: Burton
authors: Geeske
authors: G
authors: Peeters
authors: Kristiann C
authors: KC
authors: Heesch
authors: Wendy J
authors: WJ
authors: Brown
mesh_terms: D001315:Australia / Q000453:epidemiology; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology* / Q000517:prevention & control; D005260:Female; D017408:Guidelines as Topic; D006801:Humans; D016015:Logistic Models; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D011795:Surveys and Questionnaires; D013997:Time Factors