Homocysteine and B vitamins in dementia Dear Sir:

Recently, Selhub et al (1) pointed out the importance of the B vitamins folic acid, vitamin B-6, and vitamin B-12 for the well-being and normal functioning of the brain. They also mentioned that the status of these vitamins is frequently inad-equate in the elderly and that these inadequacies can result in hyperhomocysteinemia, a recently identified risk factor for atherosclerosis (2, 3) and Alzheimer disease (AD; 4). The authors further stated that these inadequacies can result in brain ischemia by way of occlusive vascular disease, stroke, or thrombosis. Vascular disease risk factors such as hypertension are well recognized in AD (5). In our own series of 31 patients with cog-nitive decline (6), 7 of 19 AD patients had one or more vascular disease risk factors (hypertension, generalized atherosclerosis, atrial fibrillation, diabetes, and hypercholesterolemia). When we measured serum concentrations of vitamin B-12, folic acid, and homocysteine in these patients, both AD patients and those with vascular dementia had similarly elevated homocysteine com-pared with concentrations in healthy control subjects of similar age (Table 1), indicating that vascular disease risk factors may contribute to the pathophysiology of AD. We found an inverse correlation between the degree of cogni-tive impairment as determined by the Mini-Mental State Exami-nation (MMSE) and homocysteine (r = 0.43; Spearman rank correlation), an inverse correlation between folic acid and homo-cysteine (r = 0.36), a correlation between MMSE and folic acid (r = 0.37), and a correlation between folic acid and vitamin B-12 (r = 0.60) (all P < 0.05). These results agree well with recent data reported by Nourhashemi et al (7), who also found a correlation between cognitive skills and B vitamins including folic acid and homocysteine. In our study, 9 of 31 patients with dementia and hyperho-mocysteinemia were treated with 50 mg vitamin B-1, 50 mg vitamin B-6, 5 mg folic acid, and 0.05 mg vitamin B-1