The effect of peripheral vascular disease on the serum levels of natural anti-oxidants: bilirubin and albumin.

Background: Bilirubin and albumin may act as antioxidants. Their circulating levels are lower in those patients with ischemic heart disease (IHD) and could be further reduced by more extensive atherosclerosis, i.e. peripheral vascular disease (PVD).
Methods: Serum bilirubin and albumin were measured in 456 patients classified into 3 groups: 1) no clinically evident cardiovascular disease (CVD), 2) IHD present and 3) PVD present. Smoking status and gender (which affect bilirubin and albumin levels in healthy individuals) were considered separately.
Results: Bilirubin was lower in smoking men without CVD or with PVD than in non-smokers (p=0.02 and p=0.04, respectively) in the same groups. Non-smoking women without CVD had significantly (p=0.004) lower bilirubin levels than the corresponding group of men. Frequency analysis of male non-smokers revealed significantly (p=0.04) more patients with a lower bilirubin (<6.5 mmol/l) in the PVD compared with the no CVD group. Albumin levels showed the same trends.
Conclusions: Prospective studies should consider smoking and gender when assessing the relevance of bilirubin and/or albumin levels in patients with vascular disease. Our findings support those of other studies that show that low serum bilirubin and albumin levels are associated with the presence of vascular disease.