Abstract
Abstract: :
Purpose: Hyperhomocysteinemia has been reported to be a major and independent risk factor for vascular thrombosis. Hyperhomocysteinemia-related vascular events have also been shown to be reversible by folate supplementation. In view of the increasing evidence suggesting a possible association between vasculopathy and age-related maculopathy (ARM), this study aimed to assess whether hyperhomocysteinemia is associated with an increased prevalence of ARM in an older Australian population. Methods: In 1992-4 the Blue Mountains Eye Study (BMES) recruited 3654 participants (82.4% of 4433 eligible residents aged 49 years and older in two postcode areas). After 5 years, 543 had died and 2335 were re-examined. This group, together with an additional 1174 (85.2% of 1378 who became eligible during the intervening period) constituted Cross-section two of the BMES (n=3509). Blood samples were taken from 2893 of 3509 (82.4%), and plasma homocysteine was measured using an IMX analyser. ARM was assessed from retinal photographs using the Wisconsin Age-related Maculopathy Grading System. Logistic regression, adjusting for age, sex and smoking, was performed and odds ratios (OR) with 95% confidence intervals (CI) were assessed. Results: Plasma homocysteine level increased with increasing age, with mean values of 10.2, 11.6, 13.5 and 15.5 µmol/L in participants aged <60, 60-69, 70-79 and 80+ years, respectively. Mean (SD) homocysteine level was also higher in participants with early (13.7 ± 5.3 µmol/L) or late ARM (14.7 ± 3.8 µmol/L), compared to those without ARM (12.0 ± 4.8 µmol/L). ARM prevalence rates among participants with the lowest to highest quintile of homocysteine were 5.2%, 6.3%, 7.9%, 11.7% and 13.1%, respectively, for early ARM; and 0%, 0.7%, 1.2%, 2.7% and 3.1% respectively, for late ARM. After adjusting for age and sex, however, the association between homocysteine and ARM disappeared (OR 1.0, 95 % CI 0.98-1.03 for each µmol/L increase in homocysteine level). The trend for association between homocysteine quintiles and late ARM was marginally non-significant (age-sex-smoking adjusted OR 1.3, 95% CI 0.98-1.68). Conclusions: Plasma homocysteine levels increased with age. A crude association found between hyperhomocysteinemia and ARM was principally due to age-related associations with both ARM and homocysteine. Longitudinal studies would be needed to ascertain if an association exists and if so to study potential benefits from folate supplementation.
Keywords: age-related macular degeneration • clinical (human) or epidemiologic studies: ris • clinical (human) or epidemiologic studies: pre