“This is the first study that definitively shows a strong association between not moving and cancer death,” lead study author Susan Gilchrist, MD, associate professor of Clinical Cancer Prevention, said in a press release. “Our findings show that the amount of time a person spends sitting prior to a cancer diagnosis is predictive of time to cancer death.”
This was a prospective cohort, U.S.-based study including 8,002 adults aged 45 years or older that took place between April 18, 2019, and April 21, 2020. Study participants were enrolled in the Reasons for Geographic and Racial Differences in Stroke study. The primary exposures were sedentary time, light-intensity physical activity (LIPA), and moderate- to vigorous-intensity physical activity (MVPA). Sedentary and activity times were measured by a hip-mounted accelerometer that participants wore for seven consecutive days. The main outcome was cancer mortality.
The 8,002 participants had a mean (SD) age of 69.8 (8.5) years, and 3,668 (45.8%) of participants were male. Mean (SD) follow-up was 5.3 (1.5) years, during which time 268 participants (3.3%) died from cancer. Multivariable-adjusted models that included MVPA found a correlation between greater total sedentary time and greater cancer mortality risk (tertile 2 vs. tertile 1: hazard ratio [HR], 1.45; 95% confidence interval [CI], 1.00 to 2.11; tertile 3 vs. tertile 1: HR, 1.52; 95% CI, 1.01 to 2.27). When adjusting for MVPA, there was not a significant correlation between longer sedentary bout duration and greater cancer mortality risk (tertile 2 vs. tertile 1: HR, 1.26; 95% CI, 0.90 to 1.78; tertile 3 vs. tertile 1: HR, 1.36; 95% CI, 0.96 to 1.93). Participants who engaged in 30 minutes of LIPA instead of sedentary time decreased their cancer mortality risk by 8% (per 30 minutes: HR, 0.92; 95% CI, 0.86 to 0.97), while 30 minutes of MVPA reduced cancer mortality by close to a third (per 30 minutes: HR, 0.69; 95% CI, 0.48 to 0.97).
Sedentary Behavior: A Little Change Goes a Long Way
“Conversations with my patients always begin with why they don’t have time to exercise,” said Dr. Gilchrist. “I tell them to consider standing up for 5 minutes every hour at work or taking the stairs instead of the elevator. It might not sound like a lot, but this study tells us even light activity has cancer survival benefits.”
The results of the study were published in JAMA Oncology.
“Our findings reinforce that it’s important to ‘sit less and move more’ and that incorporating 30 minutes of movement into your daily life can help reduce your risk of death from cancer,” Dr. Gilchrist said. “Our next step is to investigate how objectively measured sedentary behavior impacts site-specific cancer incidence and if gender and race play a role.”