A Retrospective Study of the Association between Low Vitamin B1 in the Blood and Cognitive Impairment in Patients with Alzheimer’s Disease

Abstract

This retrospective observational study investigated the association between low vitamin B1 (VB1) levels and cognitive impairment in 77 Japanese patients with Alzheimer’s disease (AD). Multivariable regression analysis identified a significant correlation between low VB1 levels (<2.6 μg/dL) and lower Mini-Mental State Examination (MMSE) scores. Fisher’s exact test demonstrated a strong association between VB1 deficiency and cognitive impairment (p=0.001). Scatter plot analysis supported these findings, illustrating a dose-dependent trend: patients with severe VB1 deficiency consistently exhibited low cognitive function, while those with higher VB1 levels showed better MMSE scores. In contrast, VB12 and folate levels showed no clear association with cognitive function. These results, together with animal studies, suggest that VB1 deficiency may contribute to AD-related neurodegeneration. While benfotiamine, a lipid-soluble VB1 derivative, has been suggested to improve cognition, its causal effect remains uncertain due to the study’s cross-sectional design. Selection bias and the lack of dietary data are also limitations. Further longitudinal research is needed to determine whether VB1 supplementation could help mitigate cognitive decline in AD patients.