Plasma Vitamin B-12 Levels and Risk of Alzheimer's Disease: A Case-Control Study

Introduction: Vitamin B-12 deficiency is a frequent condition in the elderly population. High homocysteine levels, which can contribute to arterial damage and blood clots in blood vessels, usually indicate a deficiency in vitamin B-12. Different studies have shown an association of raised total homocysteine with incident Alzheimer's disease. This study aimed to evaluate the association between vitamin B-12 levels and the risk of Alzheimer's disease (AD). Methods: A case-control study with a sample size of 90 was conducted at Tertiary hospital, Kathmandu. The participants who visited the psychiatric outpatient department from 2019 onward at Tertiary hospital, Kathmandu, were recruited. The Mini-Mental State Examination (MMSE) was administered to the participants by a trained medical doctor. The medical doctor used the MMSE scores to classify the participants into two groups: the healthy control group and the AD group. Results: The AD group had higher percentages of hypertension (20.9%), diabetes (13.6%), smoking habit (27.3%), vitamin B-12 deficiency (22.7%), and alcohol consumption (13.8%) relative to the control group. Among these features, a significant association was found between alcohol and vitamin B-12 status and between systolic blood pressure and MMSE score. Conclusion: This study concluded that there is an association between low levels of vitamin B-12 and the risk of AD. Further studies are needed to determine the cause-effect.