Breaks in sedentary time reduce functional loss in knee OA

SEATTLE — Interruptions to sedentary activity in patients with knee osteoarthritis can help minimize functional loss, according to research presented at the Osteoarthritis Research Society International World Congress on Osteoarthritis.

“Sedentary lifestyle are increasing and hazardous to health,” Julia Lee, PT, said, here. “Little is known about sedentary patterns and physical function.”

Lee and colleagues studied a cohort of 1,642 community-dwelling patients, aged 49 years to 83 years, who had radiographic knee osteoarthritis (OA) or knee OA risk factors and were enrolled in the Osteoarthritis Initiative.

Physical function was assessed at 48 months and 72 months using the 20-meter walk and chair stand tests. Accelerometers were used to assess the amount of sedentary time, frequency of breaks in sedentary time and time spent performing moderate-to-vigorous physical activity (MVPA) at baseline. Accelerometer counts of activity counts per minute were less than 100.

Patients with OA or risk factors for OA spent 9.8 hours (66% of wear time) engaged in sedentary behavior on average and had an average of 89.1 breaks in sedentary activity.

Researchers found that gait speed was reduced by 6.10 feet per minute on average after 2 years, and the chair stand rate decreased by 0.38 repetitions per minute. However, multiple linear regression adjusted for age, sex, baseline function, education level, health factors, comorbidities, BMI and other factors showed an inverse relationship between the frequency of breaks and functional loss in gait speed, but not in the chair stand rate.

Mean BMI was highest in the group who took the fewest breaks from sedentary behavior. More breaks per sedentary hour at baseline were associated with highest gait speed and association with the higher break group and lower functional loss at 2 years, Lee said.

“These findings still remain independent of the moderate activity otherwise conducted,” she said. “This finding is important for those who are designing sedentary interventions.”- by Shirley Pulawski

Reference:

Lee J, et al. Paper #4. Presented at: Osteoarthritis Research Society International World Congress on Osteoarthritis. April 30-May 3, 2015; Seattle.

Disclosure: Lee reports no relevant financial disclosures. See the full study for a list of all authors’ relevant financial disclosures.