| This thesis research explores the relationship between vitamin D, neurocognitive function, dementia, cerebrovascular disease, and depression in older adults. In a cohort of elders receiving home health services in Boston, MA we found that low vitamin D status was associated with cognitive dysfunction, Alzheimer's disease, cerebrovascular disease, and depression.;Vitamin D is a steroid hormone well known for its role in calcium homeostasis and bone mineralization. Vitamin D can be obtained from the diet or synthesized in the skin following sun exposure. The hormone is biologically inert until it is enzymatically converted to the active form. Recently, catalytic mechanisms necessary to convert vitamin D to the active form and receptors specific for the active form of vitamin D have been identified in the brain.;In vitro and animal data suggest that vitamin D may impart neuroprotective benefits through antioxidative mechanisms, neuronal calcium regulation, immunomodulation, enhanced nerve conduction and detoxification mechanisms. In addition to these functional attributes, vitamin D may preserve cognitive function through protection against cardiovascular diseases and cerebrovascular disease. Despite these potential benefits, there has been little research of vitamin D, cognitive function, and cerebrovascular disease.;In the largest population based cohort to evaluate vitamin D and cognition in elders to date, vitamin D was significantly associated with cognitive function, Alzheimer's disease, stroke, and clinical and radiographic indicators of vascular brain disease. Our findings suggest that vitamin D is inversely associated with the presence of large vessel infarcts and white matter disease. Additionally, we found that vitamin D was associated with depressive symptomatology and that the association was more pronounced in subjects with underlying cognitive impairment. Although these findings are cross-sectional and, therefore, cannot prove cause and effect, they suggest that vitamin D may be protective to subcortical function in this elderly population. Longitudinal studies are needed to clarify the causal pathway. |
