Background: Sarcopenia, defined as low muscle mass (LMM), and dynapenia have been associated with adverse outcomes in elderly.
Objective: Contrast the association of sarcopenia versus dynapenia with incidence of disability.
Design: A four-year prospective study (2006-2010).
Setting: São Paulo, Brazil.
Participants: 478 individuals aged 60 and older from the Saúde, Bem-Estar e Envelhecimento (SABE) study who were non-disabled at baseline.
Measurements: Sarcopenia, measured according to the European Working Group on Sarcopenia in Older People (EWGSOP), includes: LMM assessed by skeletal muscle mass index ≤8.90kg/m2 (men) and ≤6.37kg/m2 (women); low muscle strength (LMS) assessed by handgrip strength <30kg (men) and <20kg (women); and low physical performance (LPP) assessed by gait speed ≤0.8m/s. Diagnosis of sarcopenia required LMM plus LMS or LPP. Dynapenia was defined as handgrip strength <30kg (men) and <20kg (women). Covariates included socio-demographic and behavioral variables, medical conditions, hospitalization, depressive symptoms, cognition, perception of vision, hearing and body mass index.
Outcomes: Disability in mobility or instrumental activities of daily living (IADL) or disability in activities of daily living (ADL) and IADL.
Results: The incidence density of mobility or IADL disability was 43.4/1000 person/year and 22.6/1000 person/year for IADL and ADL disability. There was no significant difference in incidence density according sarcopenia or dynapenia status. After controlling for all covariates, sarcopenia was associated with mobility or IADL disability (relative risk ratio = 2.23, 95%Confidence Interval: 1.03-4.85). Dynapenia was not associated with disability.
Conclusions: Sarcopenia according to the EWGSOP definition can be used in clinical practice as a screening tool for early functional decline (mobility or IADL disability).