Background The operational definition of sarcopenia has been updated (EWGSOP2) and apply different cut-off points compared to previous criteria (EWGSOP1). Therefore, we aim to compare the sarcopenia prevalence and the association with mortality and dependence in activities of daily living using the 2010 (EWGSOP1 and 2019 (EWGSOP2 operational definition, applying cut-offs at two levels using T-scores.

Methods Two birth cohorts, 70 and 85-years-old (n = 884 and n = 157, respectively), were assessed cross-sectionally (57% women). Low grip strength, low muscle mass and slow gait speed were defined below − 2.0 and − 2.5 SD from a young reference population (T-score). Muscle mass was defined as appendicular lean soft tissue index by DXA. The EWGSOP1 and EWGSOP2 were applied and compared with McNemar tests and Cohen’s kappa. All-cause mortality was analyzed with the Cox-proportional hazard model.

Results Sarcopenia prevalence was 1.4–7.8% in 70-year-olds and 42–62% in 85 years-old’s, depending on diagnostic criteria. Overall, the prevalence of sarcopenia was 0.9–1.0 percentage points lower using the EWGSOP2 compared to EWGSOP1 when applying uniform T-score cut-offs (P <  0.005). The prevalence was doubled (15.0 vs. 7.5%) using the − 2.0 vs. -2.5 T-scores with EWGSOP2 in the whole sample. The increase in prevalence when changing the cut-offs was 5.7% (P <  0.001) in the 70-year-olds and 17.8% (P <  0.001) in the 85-year-olds (EWGSP2). Sarcopenia with cut-offs at − 2.5 T-score was associated with increased mortality (hazard ratio 2.4–2.8, P <  0.05) but not at T-score − 2.0.

Conclusions The prevalence of sarcopenia was higher in 85-year-olds compared to 70-year-olds. Overall, the differences between the EWGSOP1 and EWGSOP2 classifications are small. Meaningful differences between EWGSOP1 and 2 in the 85-year-olds could not be ruled out. Prevalence was more dependent on cut-offs than on the operational definition.