Background : Self-reported and wearable device derived data on physical activity (PA) differ in burden, transparency, and validity, underscoring the need for comparison in cancer survivorship research. Physical activity and sedentary behavior measured from the ActiGraph, International Physical Activity Questionnaire (IPAQ), and Fitbit Inspire device in women with early-stage breast cancer were compared. Methods : Breast cancer survivors participating in a lifestyle intervention trial concurrently provided ActiGraph and IPAQ data at baseline and 6 months. Fitbit devices were used for PA self-monitoring after randomization and data were available at follow-up only. Comparisons of PA measurements were estimated via Pearson correlation coefficients and visualized using Bland–Altman plots. Prevalence of meeting moderate to vigorous PA guidelines of ≥150 minutes per week were also calculated. Results : At baseline (n = 73), mean vigorous PA was 2 and 5 minutes per day for ActiGraph and IPAQ, respectively ( r = .22, P = .06), while mean sedentary hours per day were 11.4 and 6.2 for ActiGraph and IPAQ, respectively ( r = .29, P = .01). Correlations between ActiGraph and IPAQ at 6-month follow-up (n = 50) were not statistically significant. Six-month comparisons of PA measures between ActiGraph and Fitbit (n = 30) were higher than those between IPAQ and Fitbit (n = 30). Prevalence of meeting moderate to vigorous PA guidelines at baseline was 40% for ActiGraph and 59% for IPAQ ( P = .01). At 6 months, proportions meeting moderate to vigorous PA guidelines were 50%, 73%, and 67% for ActiGraph, IPAQ, and Fitbit, respectively. Conclusion : Correlations of PA comparing self-report from IPAQ and activity devices from ActiGraph and Fitbit were weak. Strengths and limitations of PA measurement methods should be weighed accordingly in studies of lifestyle interventions for breast cancer survivors.
Rillamas‐Sun et al. (2025) studied this question.