Predictors of objectively-measured sedentary time during the COVID-19 pandemic among breast cancer survivors participating in a diet and physical activity intervention

ABSTRACT

Purpose of the study The purpose of this study was to investigate the predictors of objectively-measured sedentary time (ST) among breast cancer (BC) survivors who were 60 days post-treatment and were initiating participation in an intervention to improve diet and physical activity (PA) during the early phase of the COVID-19 pandemic. Methods: Cook and Move for Your Life (CMFYL) was a pilot and feasibility study of stage 0-III BC survivors testing the effects of a remotely-delivered and remotely-assessed nutrition and PA intervention. Women were ≥60 days post-treatment (current endocrine therapy allowed), consumed <5 servings of fruits/vegetables per day and/or engaged in <150 minutes/week of moderate to vigorous physical activity (MVPA). Hip-worn Actigraph GT3X accelerometers measured ST for 7 consecutive days at baseline. ST was defined as minutes/day (continuous) based on the Troiano cutpoint (<100 counts/minute), during awake (6am-11pm) wear time, and non-wear was identified using the Choi algorithm on the vector magnitude counts/minute. Multivariable linear regression models adjusting for wear time (average minutes/day) and minutes of MVPA/day were used to examine whether the following factors were predictors of ST at baseline self-reported demographics, psychosocial factors (assessed via PROMIS Physical Function and PROMIS Anxiety forms), diet quality (Healthy Eating Index 2015 score), caloric intake (calories/day), and fruit and vegetable intake (servings/day). Results: Among the 84 women included in this analysis who had actigraphy measurements at baseline, the average ST/day was 684±79 minutes. On average, women were 58±10 years in age and most self-identified as non-Hispanic white (87%). The average time since diagnosis at time of enrollment was 4.5 years and 59% of women were receiving endocrine therapy at baseline. Adjusted models show that participants with a college degree had 24.7 (95%CI 2.0, 47.4) more minutes of ST than those with less than a college degree, and for every 1-point increase in PROMIS Physical Function scores participants had 2.5 (95%CI -4.9, -0.2) fewer minutes of ST. Conclusion: In a sample of BC survivors enrolled in a diet and PA intervention, higher level of education and poorer physical function were associated with higher ST during the early phase of the COVID-19 pandemic. These findings provide preliminary insight into factors associated with ST. Future work will investigate how these factors influence change in ST after participation in the CMFYL intervention.