Association between probable sarcopenia and dementia risk: a prospective cohort study with mediation analysis

The role of alcohol consumption as a mediator in the risk between sarcopenia and dementia remains inadequately studied. There is currently limited research on whether the association between sarcopenia and the risk of Alzheimer's disease (AD) is influenced by genetic susceptibility. Our study incorporated a total of 483,637 baseline non-dementia participants, who were classified into groups of individuals with no sarcopenia and those with probable sarcopenia based on the definition. We employed Cox proportional hazards models to evaluate the association between probable sarcopenia and the risk of all cause dementia (ACD), AD, and vascular dementia (VD). We conducted mediation analysis to explore the role of alcohol consumption in the association between probable sarcopenia and the risk of ACD, AD, and VD. During the median follow-up period of 13.6 years, we documented 9000 new cases of ACD (including 4061 AD and 2025 VD). Fully adjusted multivariate model revealed a significant correlation between probable sarcopenia and elevated risk for ACD (HR = 1.54, 95% CI: 1.46-1.62, p < 0.001), AD (HR = 1.32, 95% CI: 1.21-1.43, p < 0.001), and VD (HR = 1.69, 95% CI: 1.52-1.89, p < 0.001). Mediation analysis elucidates that alcohol consumption explained 12.8%, 15.2%, and 11.1% of the associations of probable sarcopenia with the risk of ACD, AD, and VD, respectively. An interactive relationship prevails between probable sarcopenia and genetic factors (p for interaction <0.001), and regardless of the degree of genetic risk, probable sarcopenia correlates with an elevated AD risk. Our study reveals a significant association between probable sarcopenia and an increased risk of dementia, with alcohol consumption playing a mediating role in this association. There is an interaction between probable sarcopenia and genetic susceptibility related to the risk of AD.