Coffee intake and risk of diabetic retinopathy: a Mendelian randomization study

Abstract Background: Observational studies have reported a link between coffee consumption and diabetic retinopathy (DR), but the causal relationship remains a subject of debate. To explore these causal associations, we conducted a Mendelian randomization (MR) study. Methods: We utilized seven publicly accessible genome-wide association studies (GWAS) datasets related to coffee intake (ukb-b-5237) and DR (finn-b-DMRETINOPATHY, finn-b-H7RETINOPATHYDIAB, finn-b-DMRETINOPATHYEXMORE, finn-b-DMRETINAPROLIF, finn-b-H7RETINOPATHYDIABPROLIF, and finn-b-H7RETINOPATHYDIABBKG). MR analyses were performed using inverse variance weighted (IVW), weighted median, MR-Egger regression, and weighted mode estimates. Results: Employing 40 single-nucleotide polymorphisms (SNPs) of genome-wide significance as instrumental variables for coffee intake, our study revealed a positive correlation between genetically predicted coffee consumption and the risk of DR (OR= 1. 39, 95% CI: 1. 02 to 1. 90, p = 0. 037; OR=2. 25, 95% CI: 1. 21 to 4. 20, p = 0. 011; OR= 1. 66, 95% CI: 1. 17 to 2. 35, p = 0. 004; OR= 1. 75, 95% CI: 1. 20 to 2. 56, p = 0. 004; OR= 2. 79, 95% CI: 1. 08 to 7. 23, p = 0. 035; OR= 2. 48, 95% CI: 1. 16 to 5. 29, p = 0. 019). These results were consistent across various sensitivity analyses and free from pleiotropy. Conclusions: Our findings indicate a positive association between coffee intake and the risk of DR, as determined by genetic data. These correlations warrant serious consideration in clinical settings.