Public Health

Sarcopenia is an age-related process characterized by the loss of muscle mass and function, being a frailty component that affects the quality of life. It has been described as a risk factor for Alzheimer's disease dementia (ADD), and the coexistence of sarcopenia and ADD is associated with worse cognitive function and poor prognosis.

This is a cross-sectional study, using data from the Cog-Aging Cohort Study, including 92 participants assessed in 2023 and 2024. The Mini-Mental State Examination (MMSE) score cut-off was 19/20 for illiterate participants and 23/24 for literate ones, and was used to determine cognitive impairment. We aimed to evaluate the effects of age, sex, presence of the apolipoprotein E (APOE) ε4 allele, and educational level on predicting MMSE status in a Logistic Regression, with a significance level of 5%. We included Body Mass Index (BMI), Timed Up and Go Test (TUG), and calf circumference (CC) as sarcopenia and frailty variables in the model.

The mean age was 78.7 years (SD±7.1); median 4 years (IQR=5) of formal education, 64.1% were female and 29.3% were ε4 carriers. The MMSE median score was 24 points (IQR=5.5) and mean BMI was 26.5 (SD=±5); TUG median was 11.9 (IQR=4.3) and mean CC 34.7 (SD=±3.5). The inclusion of sarcopenia and frailty variables improved the logistic regression model (p = 0.035, Nagelkerke's R² 0.381), thus raising the performance from 68.96% to 74.71% of cases, with an AUC of 0.810. The most important factors were ε4 allele with OR of 5.15 (p = 0.016), followed by female sex with OR 3.46 (p = 0.036), and BMI with OR 1.17 (p = 0.04). Lower CC (p = 0.008) and years of formal education (p = 0.006) were associated with impaired MMSE status. Age and TUG did not exhibit a significant association.

Participants with the APOE ε4 allele, higher BMI, female sex, lower formal education and lower CC showed poorer cognitive performance. Sarcopenia and frailty variables improved the overall model.