Relationship of Homocysteine Plasma Levels with Mild Cognitive Impairment, Alzheimer's Disease, Vascular Dementia, Psychobehavioral, and Functional Complications.

BACKGROUND Alzheimer's disease (AD) may be a vascular disorder with neurodegenerative consequences opening possibility of preventing AD by targeting vascular risk factors including homocysteine. OBJECTIVE The study aims were to assess homocysteine distribution in different forms and severity of cognitive impairment (CogI) [mild cognitive impairment (MCI), probable AD (Prob-AD), possible AD (Poss-AD), and vascular dementia (VaD)] and in NoCogI, and to estimate possible association between hyperhomocysteinemia levels with functional deficit severity and psychobehavioral complications. METHODS In total, 929 (M = 366, F = 563; mean age of 72.55±6.24 years) patients were evaluated with cognitive, neuropsychiatric, affective, and functional assessment scales. Homocysteine serum was set on two levels: between 0 and 10μmol/L and > 10μmol/L. For each patient, blood concentration of folate, vitamin B12, hemoglobin, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), cholesterol, triglycerides, and glycemia were measured. RESULTS CogI patients demonstrated significantly a higher frequency of homocysteine > 10 (p = 0.003), than NoCogI patients. Patients with moderate and severe dementia had a higher frequency of homocysteine > 10 (p   10 (p = 0.003), than Prob-AD patients. Homocysteine > 10 frequency is directly proportional to increased neuropsychiatric symptom severity (p < 0.0001), and functional impairment severity respectively for ADL (p < 0.0001) and IADL (p < 0.0001). CONCLUSION Higher homocysteine level seems to be significantly related to cognitive impairment frequency and severity, possible AD and VaD, neuropsychiatric symptom severity, and functional impairment severity.