Objectively Measured Sedentary Time Is Related to Quality of Life among Cancer Survivors
PURPOSE
While exercise has been shown to be beneficial in improving health-related quality of life (HRQOL) among cancer survivors, evidence is limited on the independent role of sedentary behavior. We examined how objectively measured sedentary time was associated with HRQOL among long-term cancer survivors.


METHODS
This cross-sectional study included 54 cancer survivors, on average 3.4 years postdiagnosis, who were enrolled into an exercise trial designed to improve cognitive function. At baseline, we measured sedentary time and moderate-vigorous intensity physical activity with the ActivPal, cardiorespiratory fitness with treadmill testing, and self-reported HRQOL with an established scale (SF-36). In multivariate models, we regressed HRQOL on sedentary time (percent of waking time spent sitting and lying).


RESULTS
Survivors with higher sedentary time had significantly poorer physical functioning (β = -0.50, p = 0.028), general health (β = -0.75, ptrend = 0.004), and physical summary scores (β = -0.34, p = 0.003). We did not observe associations between sedentary time and role-physical (p = 0.342), bodily-pain (p = 0.117), vitality (p = 0.095), social functioning (p = 0.407), role-emotional (p = 0.509), mental health (p = 0.494), or mental summary scores (p = 0.527).


CONCLUSION
In this cross-sectional study of cancer survivors, we observed deleterious associations between sedentary time and aspects of physical HRQOL. Future prospective studies of sedentary time and HRQOL are needed to establish temporality and to facilitate the design of effective health promotion interventions for cancer survivors.