title: Prospective study of physical activity and depressive symptoms in middle-aged women.
abstract: BACKGROUND
  Although many studies support an inverse association between physical activity (PA) and depressive symptoms, prospective relationships between these variables have been confounded by pre-existing psychological and physical health problems.
  
  
  METHODS
  This study examined the dose-response relationships between self-reported PA and depressive symptoms, using cross-sectional and prospective data from a population-based cohort of middle-aged women who participated in the Australian Longitudinal Study on Women's Health (ALSWH) between 1996 and 2001. Participants completed three mailed surveys (S1, 1996; S2, 1998; S3, 2001), which included questions about time spent in walking, moderate- and vigorous-intensity PA, and measures of psychological health (Center for Epidemiologic Studies Depression scale [CESD-10], and Mental health [MH] subscale of the Short Form 36 survey). Relationships between previous (S1, S2), current (S3), and habitual (S1, S2, S3) PA and "depressive symptoms" were examined, adjusting for sociodemographic and health-related variables (n=9207).
  
  
  RESULTS
  Mean CESD-10 scores decreased, and MH scores increased with increasing levels of previous, current, and habitual activity. Odds ratios for CESD-10 scores > or =10 or MH scores < or =52 at S3 were 30% to 40% lower among women who reported the equivalent of > or =60 minutes of moderate-intensity PA per week, compared with those who reported less PA than this. Women who were in the lowest PA category at S1, but who subsequently reported > or =240 metabolic equivalent minutes (MET.mins) per week had lower odds of CESD-10 scores of > or =10 or MH scores < or =52 at S3 than those who remained in the very low PA category.
  
  
  CONCLUSIONS
  These data suggest that there is a clear relationship between increasing PA and decreasing depressive symptoms in middle-aged women, independent of pre-existing physical and psychological health.
authors.affiliation: School of Human Movement Studies, The University of Queensland, Brisbane, Queensland, Australia. wbrown@hms.uq.edu.au
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Brown
authors.forename: Jessica H
authors.initials: JH
authors.lastname: Ford
authors.forename: Nicola W
authors.initials: NW
authors.lastname: Burton
authors.forename: Alison L
authors.initials: AL
authors.lastname: Marshall
authors.forename: Annette J
authors.initials: AJ
authors.lastname: Dobson
mesh_terms: D001315:Australia / Q000453:epidemiology; D016001:Confidence Intervals; D003430:Cross-Sectional Studies; D003863:Depression / Q000453:epidemiology*; D015444:Exercise / Q000523:psychology*; D005260:Female; D006304:Health Status; D006801:Humans; D008875:Middle Aged; D016017:Odds Ratio; D011446:Prospective Studies; D012959:Socioeconomic Factors