Total Plasma Homocysteine, Vitamins, Abdominal Aortic Aneurysm and Peripheral Vascular Disease

Abstract

Introduction
Hyperhomocysteinemia (>15µmol/L) is a recognised independent risk factor in the genesis of vascular diseases. There are few data on the relationship between homocysteine and abdominal aortic aneurysm (AAA), peripheral vascular disease (PVD), and the effect of vitamin B₁₂ and folic acid blood levels on plasma homocysteine concentration. This study was aimed to examine this possible relationship.

Method
Ethical approval was obtained for this case-control study. Fasting homocysteine blood levels were analysed using a fluorescence polarisation immunoassay technique. Serum vitamin B₁₂ and folic acid was analysed using chemiluminescence detection technique. Serum was separated within one hour of blood collection from antecubital venous puncture into an EDTA primed tube, from 38 patients with AAA, 36 patients with PVD and 36 control subjects for analysis of homocysteine, vitamin B₁₂ and folic acid.

Results
Twenty-six (68%) patients with AAA and 26 (72%) patients with PVD patients had elevated levels of plasma homocysteine (>15µmol/L) compared with 2 (6%) in the case controls. The mean homocysteine levels in the AAA, PVD and control groups were 19.4 ± SE 1.1 (95% CI 17.17 - 21.65), 18.4 ± SE 0.47 (95% CI 16.32 - 20.35) and 10.9 ± SE 1.0 µmols/L (95% CI 9.95 - 11.88) respectively. The difference in mean levels of homocysteine in the AAA vs the control and the PVD vs control was statistically significant (P< 0.001). Mean vitamin B₁₂ in the AAA, PVD and control groups was 332.11 ± SE 16.44 pg/L , 320.47 ± SE 16.81 pg/L and 414.33 + SE 19.72 pg/L respectively. The difference in the mean levels of serum vitamin B₁₂ in the AAA vs the control group and the PVD vs the control groups were statistically significant (P < 0.004). Mean serum folic acid for AAA, PVD and control was 8.02 ± SE 0.71 ŋgm /L , 7.84 ± SE 0.81ŋgm /L and 9.80 ± SE 0.69ŋgm /L respectively (P> 0.05). However, there was an inverse relationship between plasma homocysteine and B₁₂ (r = -0.420, P = 0.000) and, plasma homocysteine and folic acid (r = -0.326, P = 0.001).

Conclusion
This study shows significantly higher levels of plasma homocysteine in patients with AAA and PVD in comparison to control. Use of supplemental vitamins that can lower plasma homocysteine, may modify vascular disease progression. Clinical trials in this direction are warranted.

Date of Award	Aug 2003
Original language	English