ONE SIZE DOES NOT FIT ALL: PREDICTING SUBGROUPS OF BREAST CANCER SURVIVORS WHO REPORT DIFFERENT PHYSICAL ACTIVITY AND SEDENTARY BEHAVIOR FROM PRE-DIAGNOSIS TO TEN YEARS POST-DIAGNOSIS Public Deposited

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  • March 19, 2019
Creator
  • Stover, Angela
    • Affiliation: Gillings School of Global Public Health, Department of Health Behavior
Abstract
  • Purpose: Despite increasing evidence that Physical Activity (PA) and Sedentary Behavior (SB) contribute to breast cancer prognosis, little is known about changes during survivorship and whether psychosocial variables predict change. In Study 1, I determined subgroups reporting different PA and SB trajectories from pre-diagnosis through ten years post-diagnosis. In Study 2, I predicted subgroup membership based on stress and coping theory constructs. Sample: The NCI-funded Health, Eating, Activity, and Lifestyle (HEAL) study is a cohort of breast cancer survivors (stages 0-IIIA) diagnosed during 1995-1999. A subset of 938 survivors was analyzed who were ages 35-64 years at diagnosis. They were recruited from cancer registries in New Mexico, California, and Washington (36% African American, 12% Hispanic). Methods: At six months post-diagnosis, breast cancer survivors reported their pre-diagnosis PA (hours/week of moderate-vigorous PA) and SB (hours/week sitting watching TV) and current PA and SB. Follow-up interviews occurred at two, five, and ten years post-diagnosis. Subgroup membership was determined with growth mixture modeling. Mediation was examined with structural equation modeling, where demographic and clinical characteristics were predictors, stress and coping variables were mediators, and subgroups were outcome variables. Results: In Study 1, two subgroups were identified: 1) 91% reported low PA that increased from six months through five years post-diagnosis and TV watching consistent with the U.S. average of 18-19 hours/week across all time points (“Low but Increasing PA and Average TV Subgroup”); and 2) 9% reported high PA declining over time and TV watching consistent with the U.S. average but increasing over time (“High but Declining PA and Average but Increasing TV Subgroup”). In Study 2, African American breast cancer survivors with higher fatigue, greater comorbid conditions, and lower education were more likely to report poor perceived health, and in turn were more likely to be in the “Low but Increasing PA and Average TV Subgroup.” Conclusion: Despite national PA guidelines, over 90% of breast cancer survivors followed a trajectory of low PA and watching TV for 18-19 hours/week from pre-diagnosis through ten years post-diagnosis, potentially putting them at risk for poor outcomes. Study 2 results can guide development of theory-informed interventions.
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  • In Copyright
Advisor
  • Reeve, Bryce
  • Earp, Jo Anne L.
  • Rini, Christine
  • Mayer, Deborah
  • Linnan, Laura
Degree
  • Doctor of Philosophy
Degree granting institution
  • University of North Carolina at Chapel Hill Graduate School
Graduation year
  • 2015
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  • Chapel Hill, NC
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