Aim: To determine associations of accelerometer-determined total time and number of bouts of sedentary behaviour, light-intensity physical activity (PA) and moderate to vigorous intensity PA (MVPA) with sarcopenia and its components (according to the revised European Working Group on Sarcopenia in Older People definition; EWGSOP2), and incidence of 12-month falls.
Methods: 3,334 Swedish 70-year-olds had appendicular lean mass (ALM; kg) estimated by dual-energy X-ray absorptiometry. Hand grip strength (HGS) and timed up-and-go (TUG) were assessed, and sarcopenia was defined according to EWGSOP2 criteria (probable or confirmed sarcopenia). Accelerometers estimated total time in sedentary behaviour, light-intensity PA and MVPA, and also the total number of bouts of increasing duration, over seven days. Incident falls were self-reported 6 and 12 months later.
Results: Only 61 (1.8%) participants had probable or confirmed sarcopenia and 14% of participants with complete 12-month follow-up data reported a fall. After multivariable adjustment, including for other levels of activity, greater MVPA was associated with reduced likelihood of having low HGS, and greater light-intensity PA and MVPA were both associated with lower likelihood of having low ALM and slow TUG time (all P<0.05). Greater sedentary behaviour was associated with higher likelihood of having slow TUG time (odds ratio: 1.04; 95% CI 1.01-1.08 per additional hour). Only greater MVPA was associated with lower likelihood of probable or confirmed sarcopenia (0.80; 0.71-0.91 per additional hour). Similar associations were observed for the number of bouts of activity, and there was no evidence of a threshold for effects of higher duration bouts. There were no associations between total time or bouts of activity and incident falls (all P>0.05).
Conclusions: Higher total amounts of accelerometer-determined MVPA are consistently associated with reduced likelihood of sarcopenia and its components, regardless of the length of bouts of activity and also the total amount of sedentary behaviour.