Markedly lower rates of age-related macular degeneration in Malta compared to European countries : results from the Malta eye study, indicating possible divergent genetic ancestry?

Abstract

Purpose: To estimate the prevalence of age-related macular degeneration (ARMD) in a nationally representative sample of older adults from Malta, evaluate associations with established risk factors, and compare rates with those reported in other European populations, where substantial variation has been observed. Patients and Methods: A population-based cross-sectional study was conducted involving 1794 participants aged 50–80 years from Malta (1% of the represented population), recruited as part of The Malta Eye Study. Standardized ophthalmic examinations were performed, including retinal imaging graded for ARMD according to Age-Related Eye Disease Study criteria and optical coherence tomography scans. Data on demographics, medical history, behavioural risk factors, and ocular characteristics were collected via structured questionnaires. Associations were assessed using multivariable logistic regression. DNA samples were also collected for future genetic analyses. Results: The overall prevalence of ARMD was 6.5% (95% CI 5.4–7.8%), with early ARMD accounting for 5.6% (95% CI 4.6–6.7%) and late ARMD for 0.4% (95% CI 0.2–0.8%). Multivariate analysis showed that ARMD prevalence increased significantly with age (OR per year 1.08; 95% CI 1.05–1.11, p<0.001) and in the male sex (OR 1.57; 95% CI 1.01–2.44, p=0.043). The other traditional ARMD risk factors did not show significant associations in this cohort. Compared to other European populations, ARMD prevalence was notably lower. Conclusion: This study reports a relatively low prevalence of ARMD compared to other European settings, with age and male sex emerging as the only significant risk factors. The absence of association with other traditional risk factors may reflect underlying genetic differences or distinct gene–environment interactions. As DNA samples were collected, further investigation incorporating genetic data is warranted to better understand ARMD susceptibility in this population.