title: Identification and prediction of physical activity trajectories in women treated for breast cancer.
abstract: OBJECTIVE
  In this study, we aimed to identify trajectories of physical activity in a cohort of women over a 1-year period after treatment for breast cancer. We also examined factors that could predict trajectory group membership.
  
  
  METHODS
  We collected data from 199 women using questionnaires at baseline (mean = 3.46 months after treatment), and 3, 6, 9, and 12 months thereafter.
  
  
  RESULTS
  Based on semiparametric group-based modeling, there were five trajectories: consistently inactive, decreasing levels, inactive with increasing levels, somewhat active, and consistently sufficiently active. Based on logistic regression analysis, women who reported higher levels of depressive symptoms and fatigue were less likely to remain consistently sufficiently active, and women who reported higher levels of cancer worry were more likely to remain consistently sufficiently active. Age, stage of cancer, time since treatment, number of treatment types received, and number of physical symptoms did not predict trajectory group membership.
  
  
  CONCLUSIONS
  Women do not have uniform physical activity trajectories after treatment for breast cancer. Identification subgroups of women who do not remain consistently sufficiently active, and factors that predict these trajectories, can aid in the development of targeted behavior change interventions.
authors.affiliation: School of Human Kinetics, University of Ottawa, Ottawa, ON, Canada. Electronic address: jennifer.brunet@uottawa.ca.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Brunet
authors.affiliation: Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, ON, Canada.
authors.forename: Steve
authors.initials: S
authors.lastname: Amireault
authors.affiliation: Ontario Tobacco Research Unit, Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada.
authors.forename: Michael
authors.initials: M
authors.lastname: Chaiton
authors.affiliation: Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, ON, Canada.
authors.forename: Catherine M
authors.initials: CM
authors.lastname: Sabiston
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D001943:Breast Neoplasms / Q000453:epidemiology / Q000503:physiopathology* / Q000523:psychology; D003863:Depression / Q000453:epidemiology; D015444:Exercise; D005221:Fatigue / Q000453:epidemiology; D005260:Female; D006801:Humans; D008875:Middle Aged; D009367:Neoplasm Staging; D013997:Time Factors
keywords: Breast cancer; Epidemiologic factors; Physical activity; Semiparametric group-based modeling; Survivorship