Physical function-derived cut-points for the diagnosis of sarcopenia and dynapenia from the Canadian longitudinal study on aging.

backgroundAging is associated with sarcopenia (low muscle mass) and dynapenia (low muscle strength) leading to disability and mortality. Widely used previous cut-points for sarcopenia were established from dated, small, or pooled cohorts. We aimed to identify cut-points of low strength as a determinant of impaired physical performance and cut-points of low appendicular lean mass (ALM) as a predictor of low strength in a single, large, and contemporary cohort of community-dwelling older adults and compare these criteria with others.

methodsCross-sectional analyses were conducted on baseline data from 4725 and 4363 community-dwelling men and women (65-86 years, 96.8% Caucasian) of the Canadian longitudinal study on aging comprehensive cohort. Physical performance was evaluated from gait speed, timed up-and-go, chair rise, and balance tests; a weighted-sum score was computed using factor analysis. Strength was measured by handgrip dynamometry; ALM, by dual-energy X-ray absorptiometry and ALM index (ALMI; kg/m

resultsModest associations were found between ALMI and strength and between strength and physical performance score in both sexes. ALMI was not an independent predictor of physical performance score. Cut-points of <33.1 and <20.4 kg were found to define dynapenia in men and in women, respectively, corresponding to 21.5% and 24.0% prevalence rates. Sarcopenia cut-points were <7.76 kg/m

conclusionsThe proposed function-derived cut-points established from this single, large, and contemporary Canadian cohort should be used for the identification of sarcopenia and dynapenia in Caucasian older adults. We advise on using criteria based on ALMI in the diagnosis of sarcopenia. The modest agreement between sarcopenia and dynapenia denotes potential distinct health implications justifying to study both components separately.