High caffeine consumption linked to increased risk of blinding eye disease

According to an international multicenter study, drinking a lot of caffeine on a daily basis can more than triple the risk of glaucoma in those who have a genetic susceptibility to high eye pressure. The study, sponsored by Mount Sinai’s Icahn School of Medicine, is the first to show a dietary genetic link associated with glaucoma. Patients with a significant family history of glaucoma may want to limit their caffeine intake, according to research published in the June print issue of Ophthalmology.

Glaucoma is the primary cause of blindness in the United States, thus the research is essential. It investigates the effects of caffeine on glaucoma and intraocular pressure (IOP), or the pressure within the eye. Glaucoma is caused by an increase in intraocular pressure (IOP), although other variables can play a role. With glaucoma, patients typically experience few or no symptoms until the disease progresses and they have vision loss.

“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 Louis R. Pasquale, MD, lead/corresponding author and Deputy Chair for Ophthalmology Research for the Mount Sinai Health System.

The UK Biobank, a large-scale population-based biological database backed by multiple health and government institutions, was used by a team of researchers. They looked through the records from 2006 to 2010 of over 120,000 people. Participants ranged in age from 39 to 73 years old and gave health records as well as DNA samples for data collection.

They completed a series of dietary questionnaires that inquired about how many caffeinated drinks they consume on a daily basis, how much caffeine-containing food they consume, the types of caffeine they consume, and portion size. They were also asked about their eyesight, including if they had glaucoma or had a family history of glaucoma. They had their IOP examined, as well as eye measurements, three years into the research.

The researchers used multivariable analyses to look at the association between coffee intake, IOP, and self-reported glaucoma. The researchers then looked to see if factoring for genetic data changed the results. They calculated IOP genetic risk scores for each patient and ran interaction analyses.

The researchers discovered that while excessive caffeine consumption was not linked to an increased risk of higher IOP or glaucoma in general, it was linked to higher IOP and glaucoma prevalence among those with the highest genetic propensity to raised IOP – those in the top 25 percentile.

More precisely, individuals who drank the most caffeine per day—more than 480 mg, or about four cups of coffee—had a 0.35 mmHg higher IOP. Moreover, those with the greatest genetic risk score who took more than 321 milligrams of daily caffeine – nearly three cups of coffee – had a 3.9-fold greater glaucoma prevalence than those with the lowest genetic risk score who drank no or limited caffeine.

“Glaucoma patients often ask if they can help to protect their sight through lifestyle changes, however this has been a relatively understudied area until now. This study suggested that those with the highest genetic risk for glaucoma may benefit from moderating their caffeine intake. It should be noted that the link between caffeine and glaucoma risk was only seen with a large amount of caffeine and in those with the highest genetic risk,” says co-author Anthony Khawaja, MD, PhD, Associate Professor of Ophthalmology University College London (UCL) Institute of Ophthalmology and ophthalmic surgeon at Moorfields Eye Hospital. “The UK Biobank study is helping us to learn more than ever before about how our genes affect our glaucoma risk and the role that our behaviors and environment could play. We look forward to continuing to expand our knowledge in this area.

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