The global disease burden and associated risk factors of age-related macular degeneration: a comprehensive analysis

Age-related macular degeneration (AMD) is the leading cause of blindness among middle-aged and older adults, bringing a heavy health burden. Understanding the patterns of AMD disease burden and the risk factors associated with early AMD development is crucial for formulating targeted public health policies.

We estimated the prevalence of AMD and disability-adjusted life year (DALY) using data from the 2021 Global Burden of Disease (GBD). Our analysis examined trends in prevalence and DALY by age, sex, and sociodemographic index (SDI) at global, regional, and national levels from 1990 to 2021. We performed data analysis using two Mendelian randomization (MR) samples to explore the causal relationship between lipid metabolism, nutrients, and early AMD risk. The primary analysis was conducted using the inverse variance weighting method, along with a range of sensitivity analyses.

In 2021, AMD's DALY was 570,000, the age-standardized prevalence rate (ASPR) was 94.00/100,000 (95% UI, 78.32-114.42), and the age-standardized disability rate (ASDR) was 6.78/100,000 (95% UI, 4.70-9.32). The burden of AMD showed a downward trend during the study period. The disease burden is closely related to socioeconomic development and is unevenly distributed, with a heavier burden in low sociodemographic index (SDI) regions, especially in southern and central sub-Saharan Africa. Age-specific DALYs showed a gradual increasing trend, with female DALYs higher than male DALYs in all age groups. Decomposition analysis showed that population growth led to an increase in AMD DALYs. Projections from the Bayesian Age-Period Cohort (BAPC) model indicate that global AMD DALYs may continue to rise by 2045. Additionally, multivariate Mendelian randomization (MVMR) evaluation results showed that triglycerides (TG) (OR, 0.82; 95% CI, 0.73-0.92; p = 0.001) and high-density lipoprotein (HDL) (OR, 1.15; 95% CI, 1.04-1.28; p = 0.009) were significantly associated with early AMD. For every one standard deviation increase in TG levels, the risk of AMD decreases by an average of 18%. Higher TG levels are a protective factor for early AMD. However, the effect of HDL on AMD is the opposite of that of TG. For every one standard deviation increase in HDL levels, the risk of AMD increases by an average of 15%. Higher HDL levels are a risk factor for AMD.

AMD remains a major health problem worldwide, especially in low SDI regions. Population growth and aging have the most significant impact on AMD DALYs. HDL was identified as a risk factor, while TG was identified as a protective factor. These findings highlight the need for targeted interventions in low SDI regions, including dietary control, early screening, and addressing socioeconomic factors through balanced dietary plans.