Low folate status is associated with impaired cognitive function and dementia in the Sacramento Area Latino Study on Aging

Background: Low folate status is associated with poor cognitive function and dementia in the elderly. Since 1998, grain products in the United States have been fortified with folic acid, which has reduced the prevalence of folate deficiency and hyperhomocysteinemia. Objective: We investigated whether folate status is associated with cognitive function and dementia in a cohort of elderly Latinos (aged >= 60 y; n = 1789) exposed to folic acid fortification. Design: Global cognitive function was assessed by the Modified Mini-Mental State Examination (3MSE) and specific cognitive functions by cross-culturally validated neuropsychological tests. Dementia was diagnosed according to the American Psychiatric Association Diagnostic and Statistical Manual of Mental Disorders, 3rd edition revised, and California Alzheimer Disease Diagnostic and Treatment criteria. Red blood cell (RBC) folate was measured by automated chemiluminescence and total plasma homocysteine by HPLC. Results: The prevalence of folate deficiency (RBC folate <= 160 ng/mL) was <1%. After control for confounding by homocysteine, vitamin B-12, creatinine, demographic variables, and depressive symptom score, RBC folate was directly associated with 3MSE (P = 0.005) and delayed recall (P = 0.007) scores. In addition, adjusted odds ratios for low 3MSE score (!;78) and dementia diagnosis per unit increase in RBC folate were significantly below unity (P 0.008), which indicated that the relative risks of cognitive impairment and dementia decreased with increasing RBC folate concentration. In contrast, adjusted odds ratios for low 3MSE score and dementia diagnosis per unit increase in homocysteine were not significant. Conclusion: RBC folate is directly associated with cognitive function scores and is inversely associated with dementia in elderly Latinos despite folic acid fortification.