Economic estimates have indicated that 2.25 billion coffees are consumed every day – this is a significant number. Researchers at the Department of Ophthalmology, Hubei University of Medicine, Shiyan, Hubei, China, have now reported results from a genome-wide association study (GWAS) indicating a correlation between instant coffee consumption and dry AMD. Their study showed that instant coffee intake was associated with a corresponding odds ratio (OR) of approximately 6.92 for dry AMD. Following their work, clinicians may advise patients to reduce instant coffee intake based on such genetic risk profiles, offering a precision approach to reduce dry AMD risk, presented in the recent journal Food Science and Nutrition. While there was an association between instant coffee with dry AMD, there was no association with other types of coffee, and the researchers have speculated that different effects of various types of coffee on AMD may be related to manufacturing processes, additives, and other factors.
Epidemiological studies suggest that AMD affects nearly 200 million people worldwide, with the number expected to reach 290 million by 2040. While genetic and environmental factors that have shown major roles in AMD, several disease mechanisms and complexities of treatment are required to conduct current research. In their research at the Hubei University of Medicine, Shiyan, the study evaluated linkage disequilibrium score regressions (LDSC) using GWAS summary statistics, a method typically unaffected by sample overlap In particular, mendelian randomization (MR) using a method that quantitates summary data from GWAS outcomes to assess the causal effects of diseases, diet, and other factors on disease. MR controls for potential confounding factors using instrumental variables (IVs) and not affected by environmental confounding and reverse causation.
Table 1: The result of MR analysis. [The research work is licensed under a Creative Commons Attribution-Non Commercial-No Derivatives 4.0 International License, cited by Jia, Q.,, et al., entitled by: “Genetic Correlation and Mendelian Randomization Analyses Support Causal Relationships Between Instant Coffee and Age-Related Macular Degeneration”, Food Science & Nutrition, 2025; 13:e70439, https://doi.org/10.1002/fsn3.70439].
The results of the GWAS found that instant coffee appears to significantly increase the risk of AMD, with each standard deviation (SD) increases in instant coffee consumption, corresponding to an odds ratio of approximately 6.92 for dry AMD, indicating a 6.92-fold increased risk. According to the results, the authors of their paper stated that, “the current study showed that co-localization analyses did not identify shared genetic regions or variants between coffee intake and AMD, suggesting that the causal effect of instant coffee on the risk of dry AMD may not be driven by a single genetic variant, but rather involves a variety of complex biological mechanisms, including polygenic regulatory effects, gene–environment interactions, and epigenetic modifications.”