Smith_2018_11.docx (150.63 kB)
Levels and patterns of self-reported and objectively-measured free-living physical activity among prostate cancer survivors: a prospective cohort study
journal contributionposted on 2023-08-30, 15:41 authored by Lee Smith, Jung Ae Lee, Junbae Mun, Ratna Pakpahan, Kellie R. Imm, Sonya Izadi, Adam S. Kibel, Graham A. Colditz, Robert L. Grubb, Kathleen Y. Wolin, Siobhan Sutcliffe, Lin Yang
Background: No prior study has measured or compared self-reported and objectively-measured physical activity trajectories in prostate cancer survivors before and after treatment. Methods: Clinically-localized prostate cancer patients treated with radical prostatectomy were recruited from 2011-2014. Of the 350 participants enrolled at the main site, 310 provided self-reported physical activity at baseline before radical prostatectomy, and 5 weeks, 6 months, and 12 months post-radical prostatectomy. A subset of participants (n=81) provided objectively-measured physical activity at all study time points by wearing an accelerometer for seven days each. Changes in activity over time were compared using Friedman’s test. Agreement between self-reported and objective measures was evaluated using Spearman’s rank correlation coefficient. Results: Self-reported moderate-to-vigorous physical activity was high at baseline (median=32.1 minutes/day), followed by a decline at 5 weeks (15.0 minutes/day) and a recovery at 6 and 12 months (32.1-47.1 minutes/day). In contrast, objectively-measured moderate-to-vigorous physical activity was low at all four time points (median=0.0-5.2 minutes/day), with no overall change across study assessments (global p=0.29). Self-reported moderate-to-vigorous physical activity tended to be more closely related to objectively-measured light intensity physical activity (rho=0.29-0.42) than to objectively-measured moderate-to-vigorous physical activity (rho=0.07-0.27, p=0.009-0.32). Conclusions: In our population of prostate cancer survivors with critically low moderate-to-vigorous physical activity levels, self-reported measures greatly overestimated moderate-to-vigorous physical activity and may have been more reflective of light intensity physical activity. As cancer survivor guidelines were derived from self-reported data, our findings may imply that intensities of physical activity below moderate, such as light intensity, still have health benefits.
- Accepted version