Prevalence, racial variations, and risk factors of age-related macular degeneration in Singaporean Chinese, Indians, and Malays

Objective: To describe the prevalence and risk factors for age-related macular degeneration (AMD) in a multiethnic Asian cohort of Chinese, Malay, and Indian persons.

Design: Population-based cross-sectional study.

Participants: A total of 10 033 persons (3280 Malay, 3400 Indian, and 3353 Chinese; response rate, 75%) 40 years of age or older residing in Singapore.

Methods: We performed comprehensive systemic and ocular examinations, retinal photography, and laboratory investigations for all participants. We graded early and late AMD signs from retinal photographs using the modified Wisconsin AMD grading scale. We calculated the age-standardized prevalence of AMD using the 2010 Singapore adult population and analyzed risk factors for AMD using logistic regression models.

Main outcome measures: Early and late AMD.

Results: Of the 9799 participants with gradable photographs, 588 had early AMD and 60 had late AMD. The age-standardized prevalence was 5.1% (95% confidence interval [CI], 4.6-5.5) for early AMD and 0.5% (95% CI, 0.4-0.6) for late AMD. The prevalence of early AMD was similar between Chinese (5.7%) and Indian (4.5%; P = 0.27) persons and lower in Malays (3.5%; P = 0.002 compared with Chinese; P = 0.09 compared with Indians); in contrast, the prevalence for late AMD was similar across ethnic groups (Chinese, 0.6%; Indian, 0.3%; and Malay, 0.3%; P = 0.20). Risk factors for early AMD were older age (odds ratio [OR], 1.40 per 5-year increase in age; 95% CI, 1.33-1.47), male gender (OR, 1.81; 95% CI, 1.43-2.29), hypertension (OR, 1.28; 95% CI, 1.02-1.61), and hyperopic refraction (OR, 1.17 per 1-diopter increase in spherical equivalent; 95% CI, 1.11-1.24). Risk factors for late AMD include older age (OR, 1.87 per 5-year increase in age; 95% CI, 1.54-2.19), smoking more than 5 packs per week (OR, 3.63; 95% CI, 1.34-9.80), and presence of chronic kidney disease (OR, 2.17; 95% CI, 1.22-3.88).

Conclusions: Early AMD is more common in Chinese and Indians than in Malays, but there were no racial variations in the prevalence of late AMD.