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  • Routine Coffee Drinking Raises POAG Risk

    By Lynda Seminara
    Selected by Russell N. Van Gelder, MD, PhD
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    Journal Highlights

    Ophthalmology, September 2022

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    Li et al. looked at the relationship between coffee consumption and the risk of primary open-angle glaucoma (POAG). Using several sets of instrumental genetic variables to assess possible causal links, they found that habitual coffee drinking significantly raises the risk of POAG.

    In their two-sample Mendelian randomized (MR) study, single-nucleo­tide polymorphisms (SNPs) related to coffee consump­tion were selected from a previous genome-wide association study (GWAS) of 121,824 people of mainly Europe­an descent. Phenotype 1 represented six SNPs and the number of cups of coffee consumed per day. Phenotype 2 involved three SNPs reflecting the level of daily coffee intake. In addition, the biobank of the Medical Research Council (MRC) Integrative Epidemi­ology Unit at the University of Bris­tol (MRC-IEU UK), which represents nearly 429,000 European individuals, was searched for relevant content. Sum­mary-level POAG data were obtained from publicly available meta-analyses involving 16,677 patients with POAG and 199,580 controls. The inverse variance-weighted (IVW) method was used for the primary MR analysis, and POAG diagnosis was the main outcome measure. Sensitivity analyses included weighted median, mode-based estimate (MBE), the MR Pleiotropy Residual Sum and Outlier (PRESSO) test, and MR-Egger regression.

    According to the IVW analyses, POAG risk was elevated with pheno­type 1 (odds ratio [OR], 1.241) and phenotype 2 (OR, 1.155). When the same methodol­ogy was applied to GWAS data from the MRC-IEU UK biobank, the association was even stronger (OR, 1.727). For both phenotypes, results of sensi­tivity analyses for weighted median, weighted MBE, and MR-Egger were similar. Causality was confirmed by the Steiger directionality test. The intercepts derived from MR-Egger regression analysis and the global MR-PRESSO test were not statistically significant. An investigation of SNP-associated secondary phenotypes using online databases showed no evidence of traditional POAG risk factors, suggesting the lack of alternate causal pathways.

    This research indicates that POAG risk is elevated for people with genetic SNPs for high coffee consumption. The authors hope their findings will lead to better strategies to prevent and manage POAG in at-risk individuals. They recommend MR studies of individual-level data to explore dose-response relationships between coffee intake and POAG risk and to confirm their find­ings in larger GWAS samples as they become available.

    The original article can be found here.