Epidemiological studies suggested that elevated plasma homocysteine (Hcy) is associated with an increased risk of depression and cerebrovascular disease (CVD). There were few published reports of Hcy levels and methylenetetrahydrofolate reductase (MTHFR) C677T genotype in geriatric depression.

To investigate the relationship among plasma Hcy level, MTHFR C677T polymorphism and geriatric depression in the Chinese population.

The plasma Hcy level measured by capillary electrophoresis with ultraviolet detection and the C667T polymorphism of MTHFR detected using polymerase chain reaction-restriction fragment length polymorphism assay were determined in 116 patients with geriatric depression and in 80 healthy controls.

The plasma Hcy level in the patients with geriatric depression was significantly higher than that in controls (p < 0.001). The age of first episode and comorbid CVD were significantly correlated with plasma Hcy levels in geriatric patients (p = 0.014 and 0.008, respectively). The Hamilton Rating Scale for Depression total score and plasma Hcy level at baseline showed no significant correlation in the patients (r = −0.111, p = 0.397). There were no significant differences in the MTHFR C677T polymorphism genotypes and alleles between the patients and the healthy controls (p = 0.654 and 0.573, respectively).

The elevated plasma Hcy level is a risk factor for geriatric depression. MTHFR C667T genotype is not associated with geriatric depression in the Chinese population.