Plasma homocysteine, apolipoprotein E status and vascular disease in elderly patients with mental illness

Total plasma homocysteine (tHcy) concentration is increased in elderly patients with mental illness. Also, patients with vascular disease have significantly higher plasma tHcy concentration compared with patients without vascular disease. Apolipoprotein E (apoE) status is associated with cardiovascular disease and a major genetic risk factor is inheritance of the e4 allele. In the present study, we investigated the association between plasma tHcy and apoE status.

The relation between apoE status, plasma tHcy and vascular disease was investigated in a cohort of consecutively enrolled elderly patients with mental illness (n=328).

Plasma tHcy concentrations were increased (p<0.01) in carriers of APOE4 (13.6 micromol/L; 9.2-21.7 micromol/L) compared to non-carriers (12.4 micromol/L; 8.3-19.9 micromol/L). The proportion of patients with vascular disease was significantly (p<0.001) increased among carriers (61%) compared to non-carriers (42%). An increased percentage (p<0.001) of APOE4 carriers was observed in patients with Alzheimer's disease (AD) with (71%) or without vascular disease (42%), and in patients with vascular dementia (VaD) (54%) compared to a reference group (34%).

Since carriers of APOE4 showed an increased likelihood of vascular disease, these patients need more intensive control of other modifiable vascular risk factors. Furthermore, the association between plasma tHcy and the presence of APOE4 might be attributed to an increased proportion of vascular disease in APOE4 carriers.