BACKGROUND: High concentrations of homocysteine and low concentrations of vitamin B-12 and folic acid are frequently observed in subjects with dementia. OBJECTIVE: We assessed whether serum concentrations of homocysteine, vitamin B-12, or folic acid predict cognitive decline in old age. DESIGN: This was a prospective, population-based, longitudinal study of 599 subjects (Leiden 85-Plus Study, Netherlands). The subjects were administered a battery of cognitive tests (including the Mini Mental State Examination, the Stroop test, a letter digit coding test, and a word recall test) at 85 y of age and yearly thereafter until 89 y of age. Serum concentrations of homocysteine, vitamin B-12, and folic acid were measured at 85 and 89 y of age. Cross-sectional associations between serum concentrations and cognition were assessed at 85 and 89 y of age. The association between baseline serum concentrations and subsequent longitudinal cognitive decline was assessed with the use of mixed linear models. RESULTS: In the cross-sectional analyses, serum concentrations of homocysteine and folic acid were significantly associated with cognitive performance, but serum concentrations of vitamin B-12 were not. In the longitudinal analyses, there were no significant associations of serum concentrations of homocysteine, vitamin B-12, or folic acid with rate of cognitive decline. CONCLUSIONS: Elevated serum concentrations of homocysteine and reduced folic acid are associated with cognitive impairment in elderly persons but do not predict an increased rate of cognitive decline. The association of high serum concentrations of homocysteine and low folic acid with cognitive impairment in old age is likely to be a consequence of disease and not a contributory cause.
BACKGROUND: High concentrations of homocysteine and low concentrations of vitamin B-12 and folic acid are frequently observed in subjects with dementia. OBJECTIVE: We assessed whether serum concentrations of homocysteine, vitamin B-12, or folic acid predict cognitive decline in old age. DESIGN: This was a prospective, population-based, longitudinal study of 599 subjects (Leiden 85-Plus Study, Netherlands). The subjects were administered a battery of cognitive tests (including the Mini Mental State Examination, the Stroop test, a letter digit coding test, and a word recall test) at 85 y of age and yearly thereafter until 89 y of age. Serum concentrations of homocysteine, vitamin B-12, and folic acid were measured at 85 and 89 y of age. Cross-sectional associations between serum concentrations and cognition were assessed at 85 and 89 y of age. The association between baseline serum concentrations and subsequent longitudinal cognitive decline was assessed with the use of mixed linear models. RESULTS: In the cross-sectional analyses, serum concentrations of homocysteine and folic acid were significantly associated with cognitive performance, but serum concentrations of vitamin B-12 were not. In the longitudinal analyses, there were no significant associations of serum concentrations of homocysteine, vitamin B-12, or folic acid with rate of cognitive decline. CONCLUSIONS: Elevated serum concentrations of homocysteine and reduced folic acid are associated with cognitive impairment in elderly persons but do not predict an increased rate of cognitive decline. The association of high serum concentrations of homocysteine and low folic acid with cognitive impairment in old age is likely to be a consequence of disease and not a contributory cause.
Authors: Eliseu Felippe dos Santos; Estela Natacha Brandt Busanello; Anelise Miglioranza; Angela Zanatta; Alethea Gatto Barchak; Carmen Regla Vargas; Jonas Saute; Charles Rosa; Maria Júlia Carrion; Daiane Camargo; André Dalbem; Jaderson Costa da Costa; Sandro René Pinto de Sousa Miguel; Carlos Roberto de Mello Rieder; Moacir Wajner Journal: Metab Brain Dis Date: 2009-03-18 Impact factor: 3.584
Authors: Marjorie G Garrod; Ralph Green; Lindsay H Allen; Dan M Mungas; William J Jagust; Mary N Haan; Joshua W Miller Journal: Clin Chem Date: 2008-05-01 Impact factor: 8.327