Serum Homocysteine and Folate Levels are Associated With Late-life Dementia in a Korean Population

Objectives: We aimed to determine whether serum levels of homocysteine (Hcy) and its biological determinants, folate and vitamin B₁₂, are related to cognitive decline in elderly people. Methods: The concentrations of total Hcy, folate, and vitamin B₁₂ were measured in serum samples from 424 cognitively normal controls, 382 mild cognitive impairment patients, and 56 dementia patients from Ansan Geriatric cohort. The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery was used to evaluate cognitive functions. Results: The dementia patients had higher serum Hcy (dementia, 17.6±6.9μmol/L; control, 12.9±5.0μmol/L; p<0.001) and lower serum folate (dementia, 7.9±4.8ng/mL; control, 10.0±7.1ng/mL; p=0.034) levels compared with controls. There was an inverse relationship between Hcy levels and serum folate or vitamin B₁₂ concentrations. The cognitive status as measured by the (CERAD) score was inversely related to Hcy levels. The adjusted odds ratio of dementia was 5.18 (95% confidence interval: 1.91-14.10; p=0.001) for moderate (30≥Hcy>15) hyperhomocysteinemia compared with normal Hcy levels (≤15μmol/L). In addition, there was weak association between low serum folate (<3.0ng/mL) and the risk for dementia (crude odds ratio=3.68; 95% confidence interval: 1.07-12.69; p=0.039). Conclusion: Elevated serum Hcy and decreased serum folate concentrations are associated with the risk of dementia in Korean elders.