High Caffeine Intake Increases Risk of Glaucoma for Some But Not All People

Consuming large amounts of daily caffeine may increase the risk of glaucoma more than threefold for those with a genetic predisposition to higher eye pressure according to research led by the Icahn School of Medicine at Mount Sinai. The study, published in the June issue of Ophthalmology, suggests patients with a strong family history of glaucoma should cut down on caffeine intake.

"We previously published work suggesting that high caffeine intake increased the risk of the high-tension open angle glaucoma among people with a family history of disease. In this study we show that an adverse relation between high caffeine intake and glaucoma was evident only among those with the highest genetic risk score for elevated eye pressure," says lead author Louis R. Pasquale.

The team analyzed records of more than 120,000 participants between 2006 and 2010 from the UK Biobank. Participants were between 39 and 73 years old and provided their health records along with DNA samples, collected to generate data. They answered repeated dietary questionnaires focusing on how many caffeinated beverages they drink daily, how much caffeine-containing food they eat, the specific types, and portion size. They also answered questions about their vision, including specifics on if they have glaucoma or a family history of glaucoma. Three years into the study later they had their IOP checked and eye measurements.

Researchers first looked at the relationship looked between caffeine intake, IOP and self-reported glaucoma by running multivariable analyses. Then they assessed if accounting for genetic data modified these relationships. They assigned each subject an IOP genetic risk score and performed interaction analyses.

The investigators found high caffeine intake was not associated with increased risk for higher IOP or glaucoma overall; however, among participants with the strongest genetic predisposition to elevated IOP,  in the top 25 percentile,  greater caffeine consumption was associated with higher IOP and higher glaucoma prevalence. More specifically, those who consumed the highest amount of daily caffeine, more than 480 milligrams which is roughly four cups of coffee, had a 0.35 mmHg higher IOP. Additionally, those in the highest genetic risk score category who consumed more than 321 milligrams of daily caffeine,  roughly three cups of coffee,  had a 3.9-fold higher glaucoma prevalence when compared to those who drink no or minimal caffeine and in lowest genetic risk score group.