Relationships between sarcopenia, depressive symptoms, and mild cognitive impairment in Chinese community-dwelling older adults

Mild cognitive impairment (MCI) represents an intermediate state between normal cognitive aging and dementia. We aimed to investigate the association and mediation pathways of sarcopenia, including its individual components (muscle mass, muscle strength, and physical performance), and depressive symptoms with MCI in the older adults. This study consisting of 1394 community-dwelling Chinese older adults aged 60 years and older in Tianjin and Shanghai, China. Sarcopenia was defined according to the Asian Working Group for Sarcopenia (AWGS) criteria. Depressive symptoms were evaluated by the 30-item Geriatric Depression Scale (GDS). Cognitive function was assessed by Mini-Mental State Examination (MMSE), the Chinese version of the Dementia Rating Scale (CDRS) was used to apply the diagnostic of non-dementia, and instrument activities of daily living (IADL) were used to evaluate daily living activities. Logistic regression and mediation analyses fully adjusted for all potential confounding factors were conducted. Sarcopenia, handgrip strength, gait speed, and depressive symptoms were associated with MCI. Furthermore, depressive symptoms significantly mediated the association of sarcopenia, handgrip strength, and gait speed with cognitive function. The relationship of depressive symptoms and cognition were also mediated by sarcopenia, handgrip strength, and gait speed. This is a cross-sectional study. Our findings suggest that sarcopenia may contribute substantially to the development of MCI in the older adults via depressive symptoms, although the reverse may also be true. These findings may help guide clinicians to better diagnose and manage MCI in the context of concomitant sarcopenia and depressive symptoms.