ASPO Abstracts
Identifying distinct physical activity trajectories after a breast cancer diagnosis: the Pathways Study
Category: Lifestyles Behavior, Energy Balance & Chemoprevention, Behavioral Science & Health Communication
Conference Year: 2018
Abstract Body:
Objective: To identify subgroups of breast cancer (BC) patients based on distinct trajectories of physical activity (PA) after a BC diagnosis, and to examine if socioeconomic, stress coping and cancer treatment-related factors are predictors of these trajectories. Methods: The analysis used data from the Pathways Study, a population-based prospective cohort study of 4,505 women newly diagnosed with BC within the Kaiser Permanente Northern California between 2008 and 2013. Self- reported time spent on moderate-to-vigorous physical activity (MVPA) and sedentary behavior were collected using the Arizona Physical Activity Questionnaire at baseline, 6 and 24 months. Group-based trajectory modeling and K-means for longitudinal data analysis were used to identify trajectories of MVPA and sedentary behavior in 2,995 women with 2 PA assessments. Trajectory groups were defined based on baseline activity level (high, medium, low), direction of change (increase or decrease), and persistence of change (temporary or stable). Multinomial logistic regression was used to examine factors associated with MVPA and sedentary behavior trajectories. Results: During the 24 months after a BC diagnosis, trajectory analyses identified three distinct trajectories of MVPA [high decrease-temporary (7%), medium decrease-temporary (35%), low stable (58%)] and four trajectories of sedentary behavior [high-stable (18%), medium increase-stable (24%), medium decrease-stable (27%), low stable (31%)]. Compared to participants in the low stable MVPA trajectory, women who followed the high or medium decrease-temporary MVPA trajectory had higher education, income, dispositional optimism, and perceived social support (all P <0.05). Compared to the low stable trajectory of sedentary behavior, the high-stable and medium decrease-stable trajectories were associated with higher education, lower income, and higher perceived social support (all P <0.05). Conclusion: While most BC survivors in the Pathways Study maintained MVPA levels over 24 months after diagnosis, a considerable proportion of BC survivors reported decreased MVPA during this time. Higher education, optimism and perceived social support consistently characterized women with higher MVPA and lower sedentary behavior trajectories.
Keywords: physical activity, trajectory analysis, breast cancer survivor