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Sedentary behavior increases mortality risk for frail, inactive adults

The risk of death was heightened by sedentary time for frail adults who were inactive, according to findings published in the Canadian Medical Association Journal. However, results did not hold true for non-frail people who were inactive.

“Sedentary behaviors are increasingly recognized as conferring health risks, independent of physical activity,” Olga Theou, PhD, from the division of geriatric medicine at Dalhousie University, and colleagues wrote.

“Yet, no studies have examined whether the effect of sedentary behaviors on adverse health outcomes differs across levels of frailty,” they added. “Such an understanding is vital if we are to systematically address sedentary behavior among older people as a risk factor for adverse outcomes.”

Theou and colleagues sought to evaluate how the association between sedentary behaviors and higher risk of mortality was impacted by level of frailty. They examined data from the 2003-2004 and 2005-2006 cohorts of the U.S. National Health and Nutrition Examination Survey, which included 3,141 community-dwelling adults aged 50 years or older. The researchers used uniaxial accelerometers to measure time engaged in sedentary behaviors and a 46-item frailty index to measure frailty. Frailty index scores were categorized into four groups, including low levels of frailty ( 0.1), vulnerable (0.1 < frailty index score 0.2), frail (0.2 < frailty index score 0.3) and moderate-to-severe frailty (> 0.3). Participants were followed until 2011 or death.

Results showed that regardless of physical activity level, sedentary time did not predict mortality for participants with a frailty index score of no more than 0.1, indicating low levels of frailty (HR = 0.90; 95% CI, 0.70–1.15). Higher mortality was associated with sedentary time, but only among participants who did not meet the criteria for moderate physical activity and were vulnerable with a frailty index score of less than 0.1 and less than or equivalent to 0.2 (HR = 1.16; 95% CI, 1.02–1.33) or frail with a frailty index score greater than 0.2 (for the group defined by 0.2 < frailty index score 0.3: HR = 1.27, 95% CI, 1.11–1.46; for the group with frailty index score greater than 0.3: HR = 1.34, 95% CI, 1.19–1.50).

“We found that in people who scored low on the frailty index, sitting time was not linked to risk of death,” Theou said in a related press release. “Prolonged sitting was associated with a higher risk of death only in vulnerable or frail people who did not meet the weekly recommendation for 2.5 hours of moderate physical activity.”

“Physicians should stress the harms of inactivity with patients, similar to the harms of smoking, to encourage movement,” she added. “Even something as simple as getting up and walking around the house with a walker or cane can benefit frailer people.”

Previous research has shown that frailty in older adults associated with new, worsening disability following critical illness. – by Alaina Tedesco

Disclosure: Theou reports no relevant financial disclosures.