RESUMEN
BACKGROUND: Sarcopenia is defined as a progressive and generalized loss of skeletal muscle mass and strength. The specific threshold of muscle weakness that leads to mobility limitations has not been identified. OBJECTIVES: To determine the best cutoff point of handgrip strength for identifying mobility limitation and to investigate the factors associated with muscle weakness and mobility limitation in community-dwelling older people. DESIGN: Transversal study. SETTING: Cities of Belo Horizonte, Barueri and Santa Cruz in Brazil. PARTICIPANTS: 1374 community-dwelling older people from the Frailty study in Brazilian older people (FIBRA Study). MEASUREMENTS: Outcomes included muscle weakness determined according to gender-specific handgrip strength cutoff points generated by Receiver Operating Characteristic curves, mobility limitation defined as a gait speed ≤ 0.8 m/s; and a combination of both muscle weakness and mobility limitation. Associated factors included socio-demographic variables, lifestyle, anthropometrics, health conditions, use of health services and disability. RESULTS: The cutoff points of handgrip strength with the best balancing between sensitivity and specificity for mobility limitation were 25.8 kgf for men (sensitivity 69%, specificity 73%) and 17.4 kgf (sensitivity 60%, specificity 66%) for women. Age and disability in instrumental activities of daily living were associated with all outcomes. Women had greater odds of mobility limitation than men. Physical inactivity, body fat, diabetes, depression, sleeping disturbances, number of medications and occurrence of falls remained as significant associated factors in the final model. CONCLUSIONS: Handgrip strength can be a useful tool to identify mobility limitation in clinical practice. Interventions to prevent or minimize impacts of sarcopenia should stimulate physical activity and improvement of body composition in addition to the management of chronic diseases and disabilities.
