title: Mediators of the resistance and aerobic exercise intervention effect on physical and general health in men undergoing androgen deprivation therapy for prostate cancer.
abstract: BACKGROUND
  The objective of the current study was to identify mediators of the effects of a combined resistance and aerobic exercise program on perceived physical and general health in men undergoing androgen deprivation therapy for prostate cancer.
  
  
  METHODS
  In total, 57 patients with prostate cancer undergoing androgen deprivation therapy were randomly assigned to 12 weeks of resistance and aerobic exercise or usual care. The outcome measures of physical and general health were assessed by standardized questionnaires. Linear regression analyses were conducted on the residual change scores of the variables. The mediating effects of fatigue, muscle strength, and functional performance on the intervention's effect on physical and general health were examined using the product of coefficients method. Bootstrapping was used to calculate the 95% confidence intervals (95% CIs).
  
  
  RESULTS
  The exercise intervention was found to significantly improve physical (beta, 5.03; 95% CI, 1.01-9.04) and general health (beta, 12.89; 95% CI, 2.24-23.54). Upper body muscle strength and walking speed significantly mediated the intervention effect on physical health (beta, 2.65; 95% CI, 0.64-5.54), accounting for 53% of the total effect. Walking speed and fatigue were found to be mediators in the intervention effect on general health (beta, 7.52; 95% CI, 2.16-16.92), accounting for 51% of the total effect.
  
  
  CONCLUSIONS
  The intervention effects on physical and general health were explained by different mediating mechanisms. Walking speed mediated the intervention effect on both physical and general health. The intervention effect on physical health was further mediated by upper body strength, whereas the effect on general health was mediated by fatigue.
authors.affiliation: EMGO Institute for Health and Care Research, Department of Epidemiology and Biostatistics, Vrije University Medical Center, Amsterdam, The Netherlands.
authors.forename: Laurien M
authors.initials: LM
authors.lastname: Buffart
authors.forename: Daniel A
authors.initials: DA
authors.lastname: Galvão
authors.forename: Mai J
authors.initials: MJ
authors.lastname: Chinapaw
authors.forename: Johannes
authors.initials: J
authors.lastname: Brug
authors.forename: Dennis R
authors.initials: DR
authors.lastname: Taaffe
authors.forename: Nigel
authors.initials: N
authors.lastname: Spry
authors.forename: David
authors.initials: D
authors.lastname: Joseph
authors.forename: Robert U
authors.initials: RU
authors.lastname: Newton
mesh_terms: D000368:Aged; D000726:Androgen Antagonists / Q000627:therapeutic use; D001835:Body Weight; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods; D005221:Fatigue / Q000139:chemically induced; D006801:Humans; D008297:Male; D053580:Muscle Strength / Q000502:physiology; D010809:Physical Fitness; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000503:physiopathology / Q000628:therapy*; D011788:Quality of Life; D011795:Surveys and Questionnaires; D016896:Treatment Outcome; D016138:Walking
chemical_list: D000726:Androgen Antagonists
keywords: exercise; health-related quality of life; mediation analysis; neoplasms