Blood homocysteine and risk of depression in the elderly.

We studied whether increased blood homocysteine is a predictor for incident depression in a population-based cohort aged >or=65. A total of 240 men and 217 women were identified at baseline and were assessed 4 years later for depression (Geriatric Depression Scale, GDS >or=10 or use of antidepressants). Risk of incident depression was estimated for the highest gender-specific tertile of baseline plasma homocysteine compared to the other tertiles combined in a reference group. As deficiencies of B(12) and folate are the main determinant of increased blood homocysteine in old age, serum concentrations of these vitamins were also measured. In women only, the highest homocysteine tertile was associated with incident depression. However, women with combined serum B(12)/folate deficiency had the highest blood homocysteine but also a lower depression risk than vitamin-replete women. In conclusion, the data only moderately support the hypothesis that blood homocysteine is a predictor of depression.