Vitamin D Deficiency and the Increased Risk of Developing Dementia and Alzheimer’s Disease. There is significant evidence supporting the inverse relationship between vitamin D deficiency and risks of dementia-related conditions including Alzheimer's disease (AD). Through an extensive review of current literature and recent studies from 2008-2017, our research explores the connection between vitamin D deficiency and the development of dementia and AD. This is significant for nursing because the patient population that is provided care by nurses is suffering from AD at an increasing rate without a cure. Vitamin D deficiency increases the risk of developing dementia and AD; therefore, the older adult and those at risk for developing AD should increase vitamin D consumption by increasing dietary intake or by taking vitamin D supplementation.