title: Demographic, clinical, psychosocial, and environmental correlates of objectively assessed physical activity among breast cancer survivors.
abstract: The aim of this study was to identify demographic, clinical, psychosocial, and environmental correlates of objectively assessed physical activity among breast cancer survivors.
  
  
  
  Baseline data were utilized from 574 female breast cancer survivors who participated in three different intervention studies: Resistance and Endurance exercise After ChemoTherapy (REACT), Exercise and Nutrition Routine Improving Cancer Health (ENRICH), and Move More for Life (MM4L). Participants were eligible if they were aged ≥18 years and had completed primary cancer treatment. Physical activity was objectively assessed by accelerometers or pedometers. Participants completed self-reported questionnaires on demographic, psychosocial, and environmental factors. Information regarding clinical factors was obtained from medical records or patient self-report. Multivariable linear regression analyses were applied on the pooled dataset to identify factors that were significantly correlated with physical activity. In addition, the explained variance of the model was calculated.
  
  
  
  The multivariable regression model revealed that older age, (β = -0.01, 95 %CI = -0.02; -0.003), higher body mass index (β = -0.05, 95 %CI = -0.06; -0.03), lower self-efficacy (β = 0.2, 95 %CI = 0.08; 0.2), and less social support (β = 0.1, 95 %CI = 0.05; 0.2) were significantly correlated with lower physical activity. This model explained 15 % of the variance in physical activity.
  
  
  
  Age, body mass index, self-efficacy, and social support were significantly correlated with objectively assessed physical activity in breast cancer survivors. It may therefore be recommended that physical activity intervention studies in these women target those who are older, and have a higher body mass index, and should operationalize behavior change strategies designed to enhance self-efficacy and social support.
  
  
  
  The REACT study is registered at the Netherlands Trial Register [NTR2153]. The ENRICH study is registered at Australian New Zealand Clinical Trials Register [ANZCTRN12609001086257]. And the MM4L study is registered at Australian New Zealand Clinical Trials Register [ACTRN12611001061921].
authors.affiliation: Department of Public and Occupational Health and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Kampshoff
authors.affiliation: School of Medicine and Public Health, Priority Research Centre for Health Behaviour, Priority Research Centre in Physical Activity and Nutrition, and Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Fiona
authors.initials: F
authors.lastname: Stacey
authors.affiliation: School of Medicine, University of Adelaide, Adelaide, Australia.
authors.forename: Camille E
authors.initials: CE
authors.lastname: Short
authors.affiliation: Department of Public and Occupational Health and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Willem
authors.initials: W
authors.lastname: van Mechelen
authors.affiliation: Department of Public and Occupational Health and the EMGO Institute for Health and Care Research, VU University Medical Center, Amsterdam, the Netherlands.
authors.forename: Mai Jm
authors.initials: MJ
authors.lastname: Chinapaw
authors.affiliation: Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Center, De Boelelaan 1089a, 1081 HV, Amsterdam, The Netherlands.
authors.forename: Johannes
authors.initials: J
authors.lastname: Brug
authors.affiliation: School of Education and Arts, Priority Research Centre for Physical Activity and Nutrition, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Ronald
authors.initials: R
authors.lastname: Plotnikoff
authors.affiliation: School of Medicine and Public Health, Priority Research Centre for Health Behaviour, Priority Research Centre in Physical Activity and Nutrition, and Hunter Medical Research Institute, University of Newcastle, Callaghan, NSW, Australia.
authors.forename: Erica L
authors.initials: EL
authors.lastname: James
authors.affiliation: Department of Epidemiology and Biostatistics and the EMGO Institute for Health and Care Research, VU University Medical Center, De Boelelaan 1089a, 1081 HV, Amsterdam, The Netherlands. l.buffart@vumc.nl.
authors.forename: Laurien M
authors.initials: LM
authors.lastname: Buffart
mesh_terms: D001943:Breast Neoplasms / Q000401:mortality / Q000628:therapy*; D003430:Cross-Sectional Studies; D003710:Demography; D004777:Environment; D015444:Exercise / Q000502:physiology*; D005081:Exercise Therapy / Q000379:methods*; D005260:Female; D006801:Humans; D008875:Middle Aged; D011584:Psychology / Q000379:methods*; D011788:Quality of Life; D012944:Social Support; D011795:Surveys and Questionnaires; D017741:Survivors
keywords: Accelerometers; Breast cancer; Correlates; Pedometers; Physical activity