High Caffeine Intake May Heighten Risk of Glaucoma in Genetically Predisposed Individuals

What: Consuming large amounts of caffeine on a daily basis increases the risk of glaucoma for people who are genetically predisposed to having higher pressure inside their eyes.

Where: Kim et al, “Intraocular Pressure, Glaucoma, and Dietary Caffeine Consumption: A Gene–Diet Interaction Study from the UK Biobank” Ophthalmology, 2020

BrightFocus Connection: Co-author Janey Wiggs, MD, of the Department of Ophthalmology, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, MA, was co-principal investigator on a National Glaucoma Research (NGR) grant and has served on the BrightFocus NGR Scientific Review Committee. Both Dr. Wiggs and co-author Louis Pasquale, MD, of the Department of Ophthalmology, Icahn School of Medicine at Mount Sinai, New York, NY, have been invited speakers at scientific meetings organized by the BrightFocus NGR program.

Why it’s important: Glaucoma is the leading cause of blindness in the United States. Glaucoma has few noticeable symptoms, and often is diagnosed at an advanced stage after vision loss has occurred. This study is the first to demonstrate a dietary-genetic interaction in the development of glaucoma.

Louis Pasquale, MD, and Janey Wiggs, MD, PhD
(courtesy of Mass Eye and Ear)

Although other factors contribute to glaucoma, high intraocular pressure (IOP) – pressure inside the eye – is the top risk factor. This international, multi-center study, led by the Icahn School of Medicine at Mount Sinai, analyzed records of more than 120,000 participants between 39 and 73 years of age from 2006 through 2010. Participants shared their health records as well as DNA samples. They also reported on how many caffeinated beverages they drink a day, and how much food containing caffeine they eat. Participants also answered questions about their vision, glaucoma status, and family history of glaucoma. Three years into the study, they had their IOP and eye measurements checked.

Overall results showed that high rates of caffeine consumption (> 480 mg, or roughly four cups of coffee per day) were weakly associated with lower IOP, and there was no notable association between caffeine consumption and glaucoma. However, when results were further analyzed, participants with the strongest genetic predisposition to elevated IOP who consumed greater amounts of caffeine experienced higher IOP and higher glaucoma prevalence. These researchers speculated that these affected individuals have a lower reserve to withstand the challenges of intermittent yet frequent acute elevations of IOP caused by caffeine consumption.

Participants who consumed the highest amount of daily caffeine–roughly four cups of coffee–had a higher IOP overall. Additionally, those in the highest genetic risk score category who consumed more than roughly three cups of coffee had a higher glaucoma prevalence when compared to those who drink no or minimal caffeine and were in the lowest genetic risk score group.

It should be noted that no one gene has been found to cause primary open-angle glaucoma, the most prevalent type, and instead numerous gene variations are believed to contribute. To calculate genetic risk, these researchers used a polygenic risk score (PRS) that combined the effects of 111 genetic variants associated with IOP.

The results suggest that patients with a strong family history of glaucoma should cut back on caffeine to curb their risk for developing clinical signs of the disease later in life.