Abstract
Purpose:
To describe the prevalence, pattern and risk factors for age-related macular degeneration (AMD) in a multiethnic Asian cohort.
Methods:
This is a population-based cross-sectional study of 10,033 persons (3,353 Chinese, 3,280 Malay and 3,400 Indian; response rate 75%) aged 40 years and older residing in Singapore. Participants underwent comprehensive systemic and ocular examination, retinal photography and laboratory investigations. Early and late AMD signs were graded from retinal photographs at a central reading centre using the modified Wisconsin AMD grading scale. Age-standardized prevalence estimates were calculated using the 2010 Singapore adult population. Risk factors for AMD were analyzed using logistic regression models.
Results:
Of 10,033 participants, early AMD was present in 588 (5.86%, 95% confidence interval [CI] 5.40%, 6.32% ) and late AMD in 63 (0.63%, 95% CI 0.47%, 0.78%). Age-standardized prevalence for early AMD was slightly lower in Malay (4.0%) than in Indian (5.1%) and Chinese (5.9%) persons aged 40 years and above (p=0.002), but for late AMD, was similar in Malay (0.4%), Indian (0.4%) and Chinese (0.6%). Risk factors for early AMD in the overall population were male gender (odds ratio [OR] = 1.69, 95% CI :1.41, 2.08, p<0.001), hypertension (OR=1.34, CI, 1.09, 1.67, p=0.007) and shorter axial length (OR = 1.27, 95% CI: 1.16, 1.40, p<0.001), and myopic refractive error was negatively associated with early AMD (OR = 0.66, 95% CI: 0.51, 0.86, p=0.002). Risk factors for late AMD include chronic kidney disease (OR = 2.5, 95% CI: 1.41, 4.42, p=0.002) and LDL-cholesterol (OR = 1.29, 95% CI: 1.00, 1.66, p=0.053). Current smoking was associated with late AMD in Malay and Chinese (OR = 2.25, 95% CI: 1.06, 4.79, p=0.035) but not in Indian. Diabetes was associated with late AMD in Chinese persons (OR = 3.93, 95% CI: 1.74, 8.93, p=0.001).
Conclusions:
The prevalence and pattern of AMD in this large multi-ethnic Asian cohort are comparable with previous data from Western populations. Male gender, hypertension, shorter axial length are significant risk factors for early AMD, while chronic kidney disease and LDL-cholesterol are risk factors for late AMD. In addition, smoking and diabetes were risk factors for late AMD in some ethnic groups. These data provide further insights into the epidemiology of AMD in Asians.