People with a parent or sibling with glaucoma should consider limiting caffeine to amount in two cups coffee One day, says Louis Pasquale, MD, an ophthalmology professor at Mount Sinai Health System in New York City.
“It’s a suggestion,” he says. “It’s not something set in stone, but if you’re interested in reducing your risk of disease, it’s something I’d definitely entertain.”
Pascal and his colleagues reported their findings Ophthalmology.
Glaucoma is damage to the optic nerve, often from increased pressure from a build-up of fluid inside the eye. It can cause blindness.
This disease is more common in people who have close family members. And researchers have identified variants in several genes that are more common in people with glaucoma.
In previous studies, people who . take large doses of caffeine There is a temporary increase in eye pressure. So researchers have wondered whether taking caffeine over a long period of time may pose a risk.
To help answer that question, Pasquale and his colleagues looked at the records of more than 100,000 people. The record comes from the UK Biobank, a large survey conducted in the United Kingdom. The record contained information about the patients’ genes, how much Tea Or the coffee they drank, their eye pressure, and whether they had glaucoma.
Looking at all the participants together, the researchers found no increased risk of glaucoma from caffeine. In fact, they found that those who got the most caffeine actually had slightly lower eye pressure.
But when they only looked at people whose genes were associated with glaucoma, they found that caffeine was also associated with higher average eye pressure and a higher risk of glaucoma.
This was especially true when they looked at 25% of people getting more than 321 milligrams of caffeine — the equivalent of three cups of coffee a day. When these people were in the top 25% of the genetic risk for increased eye pressure, they had a much higher risk of glaucoma. They were nearly four times more likely to develop the disease than those who did not consume caffeine and had the lowest 25% genetic risk.
The researchers found that caffeine and the combination of genes increased the risk of glaucoma more than either gene alone.
The researchers did not find a statistical link for higher eye pressure or glaucoma for coffee than for tea alone. But it is likely due to a statistical problem, says co-author Anthony Khawaja, associate professor at the University College London Institute of Ophthalmology. “The answer is very simple – Britain is a tea-drinking country!” he says in an email. The database probably didn’t have enough people who drank large amounts of coffee to analyze their glaucoma risk.
Top 25% for genetic risk and . for people in both the top 25% Tea Drinkers (3 to 6 cups of tea a day) were nearly three times as likely to have glaucoma, compared to the lowest 25% for tea drinkers and the lowest 25% for genetic risk.
However, this type of study cannot prove that caffeine increases the risk of glaucoma or high eye pressure, even in people with a genetic risk, Pasquale says. He and his colleagues want to conduct a follow-up study in which they give caffeine to groups of people with different genetic risk, then compare the effect on eye pressure.
Patients rely on turning to caffeine consumption as a way to treat their glaucoma, says Asaf Achiron, MD, an ophthalmologist at the Sackler Faculty of Medicine in Tel Aviv who studied the relationship between lifestyle and eye pressure. Shouldn’t. Caffeine didn’t have a big effect for most of the people in the study, he explains.
“Glaucoma is a complex disease. In some cases it continues to progress even when [eye pressure] is reduced by drops, so clearly there are more issues here than pressure,” he says in an email.
Still, the finding could be remarkable for patients, he says. “I don’t discuss tea with my patients, just measure their [eye pressure]. Maybe I should.”