Dietary Nitrate Intake Reduces Risk of Incident Open-Angle Glaucoma

W.D. Ramdas, MD, PhD

Dietary nitrate intake could be a useful option in reducing the risk of incident open-angle glaucoma (iOAG).

A team, led by W.D. Ramdas, MD, PhD, Department of Ophthalmology, Erasmus Medical Center, assessed the link between dietary nitrate intake and incident open-angle glaucoma, while evaluating the link between dietary nitrate intake and intraocular pressure.

Nitric Oxide

In past studies, investigators found nitric oxide in involved in the regulation of the intraocular pressure and in the pathophysiology of open-angle glaucoma.

However, there is limited research into the effect of dietary nitrate intake, a source of nitric oxide

However, prospective studies investigating the effect of dietary nitrate intake, a source of nitric oxide, on incident open-angle glaucoma risk.

The Study

In the prospective population-based cohort, the investigators examined 8679 participants, 7008 of which had baseline measurements of dietary nitrate intake and data on ophthalmologic examination. Of this group, 173 patients developed open-angle glaucoma during follow-up.

Each patient was matched with a control group with similar age and gender in a case-control ration of 1:5.

Incident open-angle glaucoma was significantly less frequent in the higher total nitrate quintiles (P = 0.05, Cochran-Armitage trend test) and higher vegetable nitrate quintiles (P = 0.03).

On the other hand, non-vegetable nitrate intake was not associated with less frequent incident open-angle glaucoma (P = 0.18).

After the investigators adjusted for potential cofounders, including body mass index, total energy intake, diet quality, physical activity, and follow-up time, they found total nitrate was associated with a lower incidence of open-angle glaucoma risk (OR, 0.80; 95% CI, 0.68-0.95; P = 0.02).

The team also found non-vegetable nitrate (OR, 0.66; 95% CI, 0.43–1.00; P = 0.21) was associated with a lower incidence of open-angle glaucoma risk than vegetable nitrate (OR, 0.81; 95% CI, 0.69–0.96; P = 0.03).

The investigators also found adjustments for education and smoking status did not change the results.

“Dietary nitrate intake was associated with a significant iOAG reduction,” the authors wrote. “We did not observe significant associations between dietary nitrate intake and IOP.”

The study, “Dietary nitrate intake is associated with decreased incidence of open-angle glaucoma,” was published online during the Netherlands Ophthalmological Society (NOG) Annual Congress.