Abstract
Background
Age-related macular degeneration (AMD) is one of the major causes of vision loss. Early AMD needs to be taken seriously, whereas lipid biomarkers’ casual effects on early AMD remain unclear.
Methods
In this study, a two-sample Mendelian randomization (MR) analysis was performed to systematically assess the causal relationships between seven serum lipid biomarkers, consisting of apolipoprotein A (ApoA), apolipoprotein B (ApoB), total cholesterol (CHOL), high-density lipoprotein cholesterol (HDL-C), direct low-density lipoprotein cholesterol (LDL-C), lipoprotein A [Lp(a)], and triglycerides (TG), and the risk of early AMD. Totally, 14,034 cases and 91,214 controls of European ancestry were included in the analysis (Number of SNPs = 11,304,110).
Results
MR estimates showed that a higher HDL-C level was strongly associated with increased risk of early AMD (OR = 1.25, 95% CI: 1.15-1.35, P = 2.61 × 10−8). In addition, the level of ApoA was also positively associated with the risk of early AMD (OR = 2.04, 95% CI: 1.50-2.77, P = 6.27 × 10−6). Conversely, higher LDL-C levels significantly decreased the risk of early AMD (OR = 0.90, 95% CI: 0.85-0.96, P = 2.03 × 10−3). In addition to LDL-C, higher levels of ApoB and TG were found to be positively associated with early AMD risk. Sensitivity analyses further supported these associations. Moreover, multivariable MR analyses, adjusting for the effects of correlated lipid biomarkers yielded similar results.
Conclusion
This study addresses the question of causality relationships that elevated circulating HDL-C/ApoA levels and increased risk of early AMD, whereas LDL-C, ApoB, and TG specifically reduce the risk of early AMD. These findings contribute to our better understanding of the role of lipid metabolism in drusen formation, particularly in early AMD development.
Re: Laíns et al.: Human plasma metabolomics study across all stages of age-related macular degeneration identifies potential lipid biomarkers ( Ophthalmology . 2018;125:245-254)