Biomarkers of cardiovascular disease as risk factors for age-related macular degeneration

Abstract

Purpose: To measure and contrast 2 biomarkers of cardiovascular disease, C-reactive protein (CRP) and plasma homocysteine, in individuals with age-related macular degeneration (AMD) and control individuals without AMD.

Design: Case-control study.

Participants: Seventy-nine affected individuals and 77 unaffected individuals from the AMD Genetic Study Group returned to obtain CRP and homocysteine levels.

Methods: Both affected and unaffected individuals underwent testing for CRP and homocysteine. A detailed cardiovascular history was taken.

Main outcome measures: Mean CRP and homocysteine levels in affected and unaffected individuals.

Results: Mean CRP levels for affected and unaffected individuals were 3.42 and 2.30 mg/l, respectively (P = 0.03). Mean homocysteine levels for affected and unaffected individuals were 11.72 and 8.88 micromol/l, respectively (P<0.0001). In logistic regression models, older age, higher CRP, and higher homocysteine were risk factors for AMD. There were no significant differences between cases and controls in terms of gender, diabetes, hypertension, use of statin drugs, and smoking. The control group was significantly younger and had a lower rate of vitamin usage than the affected group.

Conclusions: Elevated CRP and homocysteine levels are associated with AMD and implicate the role of chronic inflammation and atherosclerosis.