Sedentary adults at greater risk of cancer mortality

Article written by Bruce Sylvester

Physical inactivity is independently associated with an elevated risk of dying from cancer, researchers reported on June 18, 2020 in JAMA Oncology.

“This is the first study that definitively shows a strong association between not moving and cancer death,” said lead author Susan Gilchrist, M.D., associate professor of Clinical Cancer Prevention, University of Texas M. D. Anderson Cancer Center in Houston. “Our findings show that the amount of time a person spends sitting prior to a cancer diagnosis is predictive of time to cancer death.”

The investigators conducted a sub-analysis of data from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study. They analyzed data from 8,002 adults aged 45 years or older, black and white, who were enrolled in REGARDS.

They measuredsedentary time, light-intensity physical activity, and moderate- to vigorous-intensity physical activity using a hip-mounted accelerometer worn by each subject for 7 consecutive days.

The primary outcome wascancer mortality.

Of the 8,002 subjects, 3,668 were men (45.8%) and mean age was 69.8 years.

Over a mean follow-up period of 5.3 years, 268 participants (3.3%) died of cancer.

The researchers found that the most sedentary persons had an 82% higher risk of cancer mortality compared to the least sedentary.

They also reported that replacing 30 minutes of sedentary time with light-intensity physical activity was significantly associated with an 8% lower risk of cancer mortality. Moderate- to vigorous-intensity physical activity was significantly associated with a 31% lower risk of cancer mortality.

“In this cohort study, greater sedentary time, as measured with accelerometry, appeared to be independently associated with cancer mortality risk. Replacing sedentary time with either LIPA [light-intensity physical activity] or MVPA [moderate- to vigorous-intensity physical activity] may be associated with a lower risk of cancer mortality. 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.”

Gilcrist added, “Conversations with my patients always begin with why they don’t have time to exercise. “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.”