To determine the prevalence of age-related macular degeneration (AMD) and indentify its risk factors in an Oklahoma Indian population.
Cross sectional study design
A total of 1019 Oklahoma Indians who participated in baseline and second examinations of the Oklahoma Strong Heart Study were enrolled in Vision Keepers.
Retinal photographs of at least one eye were taken and graded for AMD by the University of Wisconsin Ocular Epidemiology Reading Center using the Wisconsin Age-Related Maculopathy Grading System. Retinal photographs of 986 participants were considered gradable and included in the study.
Main Outcome Measures
Age-related macular degeneration (early & late).
The overall prevalence of any AMD in the Vision Keepers study was 35.2% including a prevalence of 0.81% for late AMD. The prevalence of early AMD increased from 30.6% in those aged 48–59 years to 46.1% in age group 70–82 years. When potential risk factor was considered individually in the univariate analyses, men with hypertension had significantly higher prevalence of AMD (p=0.02) than those without hypertension. In women high density lipoprotein-cholesterol and sun exposure were positively associated with the prevalence of AMD (p=0.01) while a history of using multivitamins was associated with lower AMD prevalence (p= 0.005). When multiple risk factors were considered simultaneously in the logistic regression analyses, only age showed significant association with AMD in both men (p=0.02) and women (p <0.0001) and was the only significant risk factor in men. In women, multivitamin use and total cholesterol had significant inverse association with AMD while sun exposure and high density lipoprotein cholesterol had positive association. When men and women are combined, age and high density lipoproteincholesterol had significant positive association while total cholesterol and multivitamin use and current alcohol use showed a significant inverse association with AMD.
This study was the first to report detailed prevalence of AMD in Oklahoma Indians and its risk factors. The prevalence appeared to be relatively high as compared to other ethnic groups. Some of the modifiable risk factors identified confirmed previous findings and can be used to design preventive programs to reduce the burden of AMD, though longitudinal data are still needed.