Lipoprotein (a) as a determinant of arterial stiffness in elderly patients with type 2 diabetes mellitus

Abstract

Background: Lipoprotein (a) [Lp(a)] is known to be a risk factor for atherosclerotic disease. However, the relationship between Lp(a) and arterial stiffness has not been clarified. We investigated whether atherosclerotic risk factors, including serum Lp(a), are associated with aortic stiffness in elderly patients with type 2 diabetes mellitus.

Methods: Aortic stiffness, evaluated by using aortic pulse wave velocity, and major atherosclerotic risk factors were measured in elderly (> or =65 years) patients with type 2 diabetes mellitus. Relationships between aortic pulse wave velocity, Lp(a) and other atherosclerotic risk factors were analyzed.

Results: Among the atherosclerotic risk factors measured, age, pulse pressure, hemoglobin A1c (HbA1c), uric acid, fibrinogen, sialic acid and Lp(a) showed significant positive correlations with aortic pulse wave velocity. Lp(a) also showed significant positive correlations with pulse pressure, fibrinogen, sialic acid, apolipoprotein B and apolipoprotein B/apolipoprotein A-I ratio. The correlation between Lp(a) and aortic pulse wave velocity was independent of age, sex, blood hemoglobin A1c, uric acid and fibrinogen, history of diabetic nephropathy and therapy with lipid-lowering drugs. Apolipoprotein A-II showed a significant negative correlation with both aortic pulse wave velocity and Lp(a). The median level of Lp(a) in the highest tertile group of subjects divided by aortic pulse wave velocity was significantly higher than the median Lp(a) level in the lowest tertile. The middle and highest tertile groups of subjects divided by aortic pulse wave velocity showed significantly high odds ratios of high Lp(a) levels (> or =30 mg/dl) vs the lowest tertile.

Conclusions: Lp(a) is an independent determinant of aortic stiffness in elderly patients with type 2 diabetes mellitus.