Effect of serum vitamin D levels on neurocognitive functions in alzheimer's disease and normal population

Effect of Serum Vitamin D Levels on Neurocognitive Functions in Alzheimer's Disease and Normal Population Dementia is a syndrome that causes impairment of mental functions and impairs one's activities in daily life. Alzheimer's disease (AD) accounts for as much as 60-80% of all dementia. The main effect of vitamin D is known to provide calcium and phosphate homeostasis, but also among anti-inflammatory and immunomodulatory effects of inflammation and immunity mechanisms among tasks outside of calcium homeostasis; cell growth, differentiation and apoptosis control; there is host defense against tumorigenesis. Oxidative stress, inflammation, and neuronal calcium signaling defects are known to play an important role in the pathogenesis of Alzheimer's disease; Vitamin D is an antiinflammatory effect via APO A1 and TNF-alpha, a proinflammatory cytokine. Vitamin D protects the oxidative strate of the brain by reducing the formation of reactive oxygen radicals with antioxidant effect via NO synthase and glutamyl transpeptidase. Vitamin D and its metabolites have a neuroprotective effect by inhibiting amyloid phagocytosis and cholestasis and abnormal amyloid deposits responsible for the pathogenesis of Alzheimer's disease and regulating the activation of the enzyme phosphatase 2A, which dephosphorylates tau protein. Studies with healthy controls and Alzheimer's disease have shown that low serum 25 OH vitamin D levels are associated with increased risk of developing Alzheimer's disease and that vitamin D replacement and suprasese synaptic plasticity are reorganized. It has also been shown that treatment with low-dose vitamin D in patients with mild to moderate Alzheimer's disease has significant improvements in memory and cognitive domain. In our study, it was aimed to investigate the effects of vitamin D on cognition taking into account the known effects on cell proliferation, calcium signaling, neurotrophic factor signaling, neurotransmission, synaptic plasticity on central nervous system of vitamin D, the relationship of vitamin D deficiency to Alzheimer's disease. In this context, 85 cognitively normal patients over 60 years of age were tested with Addenbrooke's Cognitive Examination (ACE-R) test; We studied 85 patients who were diagnosed probable Alzheimer's disease according to NIA-AA criteria by using MMSE and found that serum levels of 1,25 (OH) 2 VitD3, 25(OH) Vit D3, vitamin D binding protein (VDBP), PTH, Ca. The aim of this study was to evaluate the relationship between serum vitamin D levels and neurocognitive function in Alzheimer's disease and normal population. The aim of our study is to emphasize that vitamin D correlates with cognitive functions by comparing serum vitamin D levels between healthy controls and the AH group by showing reduced vitamin D levels in the AH group compared to controls. When the results were evaluated, serum 25(OH)Vit D3 levels were found to be significantly lower in the AH group than controls, and present findings support previous studies. Serum 1,25 (OH)2 Vit D3, calcium, phosphorus, PTH levels were not significantly different between the two groups. The free VitD3, bioavailable VitD3, bioavailable Vit D3 / Total Vit D3 levels calculated for the determination of the effective form of vitamin D were found to be significantly lower than controls in the AH group. VDBP levels were found to be significantly lower in the controls than in the AH group, and it is noted that vitamin D is reduced both in serum levels and in the active form of vitamin D, and the effect of vitamin D is limited in the patient group. Our results in our study have shown that vitamin D levels in AH are low and that the active vitamin D efficiency is less bioavailable When literature information is evaluated, it is known that Vitamin D deficiency is frequent in the geriatric population due to inadequate dietary insufficiency, malabsorption, poor oral intake, decreased thickness of the skin. Low vitamin D levels in elderly patients may be a risk factor for the development of AD; the screening of serum levels, insufficiency and deficiency of the disease may be associated with the improvement in cognitive functioning in the onset of replacement therapy not yet progressing to dementia. Long-term follow-up studies starting with basal vitamin D levels in healthy controls that do not yet develop dementia, and studies evaluating cognitive improvement in patients with vitamin D deficiency who are receiving replacement therapy may shed light on our work.. Key words: Dementia, Alzheimer's disease, Vitamin D, cognition