Replacing sedentary time with 30 minutes of light or moderate physical activity cuts risk
TUESDAY, June 23, 2020 (HealthDay News) -- Greater sedentary time is independently associated with a higher cancer mortality risk, according to a study published online June 18 in JAMA Oncology.
Susan C. Gilchrist, M.D., from The University of Texas MD Anderson Cancer Center in Houston, and colleagues examined associations between accelerometer-measured sedentary behavior (total volume and accrual in prolonged, uninterrupted bouts) and cancer mortality among 8,002 black and white adults (45.8 percent male; mean age, 69.8 years) enrolled in the Reasons for Geographic and Racial Differences in Stroke study.
The researchers found that during a mean follow-up of 5.3 years, 3.3 percent of participants died of cancer. Adjusting for moderate- to vigorous-intensity physical activity (MVPA), greater total sedentary time was associated with a greater risk for cancer mortality (tertile 2 versus tertile 1: hazard ratio [HR], 1.45; 95 percent confidence interval [CI], 1.00 to 2.11; tertile 3 versus tertile 1: HR, 1.52; 95 percent CI, 1.01 to 2.27). There was no significant association between longer sedentary bout duration and greater cancer mortality risk when adjusting for MVPA (tertile 2 versus tertile 1: HR, 1.26; 95 percent CI, 0.90 to 1.78; tertile 3 versus tertile 1: HR, 1.36; 95 percent CI, 0.96 to 1.93). If light-intensity physical activity replaced 30 minutes of sedentary time, there was a significantly lower risk for cancer mortality (HR, 0.92; 95 percent CI, 0.86 to 0.97), while substitution with MVPA was significantly associated with an even larger risk reduction (HR, 0.69; 95 percent CI, 0.48 to 0.97).
"These findings suggest that the total volume of sedentary behavior is a potential cancer mortality risk factor and support the public health message that adults should sit less and move more to promote longevity," the authors write.
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