Is Vitamin D Deficiency Associated with an Increased Risk of Alzheimer's Disease in the Elderly?

Background: Alzheimer’s Disease is the most prevalent neurodegenerative disease amongst the elderly, affecting 6% of individuals aged 65 years and older, and causes inevitable psychological and physical dependency. Symptoms progress slowly and include impairment of memory and executive function, speech and comprehension difficulties, as well as psychological symptoms such as hallucinations, delusion, and depression. Although the exact causes of AD are currently unknown, research has shown that both genetic and environmental factors, including diet, play a role. Specifically, there has been a greater interest in whether vitamin D deficiency increases the risk of developing Alzheimer’s disease in the elderly population. Processes that are affected in Alzheimer’s include calcium homeostasis, neurotransmission, aß and tau protein accumulation, oxidative stress, and inflammation, which are all influenced by vitamin D levels. Objective: To evaluate the association between vitamin D deficiency and the risk of developing Alzheimer’s disease in the elderly. Methods: A structured literature review was conducted using the PubMed and Scopus databases. Relevant studies were obtained using the following keywords: “Alzheimer’s Disease”, “vitamin D”, “deficiency”,“dementia”, and “elderly”. Only peer-reviewed articles published within the last 15 years were used. Results: The keyword searches identified 43 potentially relevant reports, which were screened against the exclusion criteria to obtain the 8 articles which were analyzed, including 4 meta-analyses. Conclusion: The evidence strongly supported an association between vitamin D deficiency and an increased risk of developing Alzheimer’s disease, in individuals aged 65 years and over. Further research is required to confirm the relationship and assess the potential advantages of vitamin D supplementation in reducing the risk of developing Alzheimer’s disease