Lipoprotein(a), homocysteine, and retinal arteriosclerosis

Abstract

Purpose: Elevated levels of lipoprotein(a) [Lp(a)] and homocysteine (Hcy) have been implicated as risk factors for vascular diseases. The study was performed to explore the possible relationship between retinal arteriosclerosis and serum Lp(a) and Hcy levels.

Methods: Study subjects consisted of 80 nonsmoking male patients with retinal arteriosclerosis and 54 healthy nonsmoker males as controls. Retinal arteriosclerosis was graded according to the Scheie classification. Serum levels of lipids, lipoproteins, Lp(a), and Hcy were measured by standard methods.

Results: The serum level of Hcy was higher in patients (24.2+/-8.1 micromol/l) than controls (10.5+/-4.1 micromol/l); p<0.01. Serum levels of Lp(a) in patients (47.9+/-33.1 mg/dl) was also higher than controls (11.7+/-7.6 mg/dl); p<0.01. There was a significant direct linear correlation between the degree of retinal arteriosclerosis and Lp(a) level (r=0.61, p<0.01), the degree of retinal arteriosclerosis and Hcy level (r=0.72, p<0.01), and also between Lp(a) and Hcy levels (r=0.67, p<0.01).

Conclusions: The association between retinal arteriosclerosis and serum Lp(a) and Hcy levels suggests that Lp(a) as well as Hcy could play a role in the development of retinal arteriosclerosis.

Figure 1

Relationship between Hcy level and the degree of retinal arteriosclerosis. There was a direct linear correlation between Hcy level and the degree of retinal arteriosclerosis in the study population (r=0.72, p<0.01), i.e. patients with higher degree of retinal arteriosclerosis had higher level of Hcy.

Figure 2

Relationship between Lp(a) level and the degree of retinal arteriosclerosis. There was a direct linear correlation between Lp(a) level and the degree of retinal arteriosclerosis in the study population (r=0.61, p<0.01), i.e. patients with higher degree of retinal arteriosclerosis had higher level of Lp(a)

Figure 3

Correlation of Hcy level with Lp(a) level. There was a direct linear correlation between Hcy and Lp(a) levels in the study population (r=0.67, p<0.01), i.e., higher level of Hcy was associated with higher level of Lp(a).

Figure 4

Receiver operating characteristic curves for arteriosclerosis. Shown is the relationship of sensitivity to 1-specificity as plotted for lipoprotein(a) and homocysteine. The area under each receiver operating characteristic (ROC) curve for each parameter indicates its diagnostic accuracy (Table 3).