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 B(12), are related to cognitive decline in elderly people. METHODS: The concentrations of total Hcy, folate, and vitamin B(12) 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 ± 6.9 μmol/L; control, 12.9 ± 5.0 μmol/L; p < 0.001) and lower serum folate (dementia, 7.9 ± 4.8 ng/mL; control, 10.0 ± 7.1 ng/mL; p = 0.034) levels compared with controls. There was an inverse relationship between Hcy levels and serum folate or vitamin B(12) 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 (≤15 μmol/L). In addition, there was weak association between low serum folate (<3.0 ng/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.