A sarcopenia e seus estágios são fatores de risco para declínio do desempenho cognitivo em pessoas idosas?

Abstract

The muscle–brain axis has emerged as a central mechanism underlying the interdependence between sarcopenia and cognitive decline, suggesting that muscle integrity influences neurobiology and the maintenance of cognitive function. Although cross-sectional evidence links losses in muscle strength and mass to poorer cognitive performance, longitudinal research remains limited in demonstrating a gradient of risk across the severity stages of sarcopenia. Moreover, it remains unclear how variability in the criteria used to define low muscle strength (LMS) modulates these associations over time. Thus, this study examined sarcopenia and its stages as risk factors for decline in global cognitive function, memory, and executive function over eight years of follow-up, considering different cut-off points to define LMS (<36, <32, <30, <27, and <26 kg for men; <23, <21, <20, and <16 kg for women). This longitudinal study used data from the English Longitudinal Study of Ageing and followed 4,301 participants aged ≥60 years, without dementia and with baseline cognitive performance (z-score) ≥ −1.5 SD. Sarcopenia was defined according to EWGSOP2 criteria using different LMS cut-offs. Global cognition, memory, and executive function were standardized as z-scores by age and education. Generalized linear mixed models adjusted for sociodemographic, behavioral, and clinical characteristics were used to estimate cognitive trajectories according to sarcopenia stages. Only severe sarcopenia was a risk factor for decline in global cognitive function and its domains, regardless of the LMS cut-off adopted. For global cognition, this corresponded to a decline ranging from −0.92 to −0.69 SD over eight years, depending on the criterion. For executive function, the decline ranged from −0.38 to −0.18 SD, and for memory from −0.30 to −0.11 SD. Severe sarcopenia was consistently associated with decline in global cognition, memory, and executive function in older adults. Because this risk was identified independently of the LMS threshold applied, higher cut-off values may help identify individuals at risk of cognitive decline at earlier stages, enabling more timely interventions.