Association Between Sarcopenia And Brain Amyloid-Β Positivity Among Community-dwelling Older Adults

Sarcopenia has been recognized as a significant predictor of cognitive impairment, fall risk, and elevated mortality. Despite evidence associating body mass index and body composition with amyloid-β (Aβ) deposition, their association with sarcopenia remains unexplored. PURPOSE: To determine the association does exists between sarcopenia and brain Aβ deposition in community-dwelling older adults. METHODS: Participants in this cross-sectional study were community-dwelling older adults aged ≥65 years without dementia who underwent comprehensive geriatric medical checkups, including Aβ positron emission tomography (PET) in the Tokyo metropolitan area. The Asian Working Group on Sarcopenia 2019 criteria were used to diagnose sarcopenia (using skeletal muscle mass index, handgrip strength, and gait speed). We constructed a binomial logistic regression model with Aβ positivity-negativity as the dependent variable and sarcopenia as the explanatory variable. Multivariate odds ratios were calculated after adjusting for the sex, age, blood pressure, medications (hypertension, diabetes mellitus), moderate-to-vigorous physical activity, sleep duration (both assessed by 3-axis accelerometer), and apolipoprotein (APO) E phenotype. RESULTS: Of 150 older adults, 126 (78.9 ± 4.0 years, 72.2% women) without missing data were included in the analysis. Of the 43 Aβ-positive participants (34.1%), 11 were APOE e4 phenotype carriers (25.5%). Nine and 12 of the Aβ-positive (10.8%) and negative (27.9%) participants, respectively, were diagnosed with sarcopenia (n = 21). After adjusting for the sex, age, blood pressure, medications, physical activity, sleep duration, and APOE gene, the multivariable odds ratio (95% confidence intervals) for Aβ-positivity in sarcopenia was 3.74 (1.31, 10.73). CONCLUSION: Our findings suggest an association between sarcopenia and brain Aβ positivity in older adults. These results underscore the need for longitudinal studies to investigate and clarify this association. This research was financially supported by Otsuka Pharmaceutical Co., Ltd. And an internal operational grant from TMIG.