Glaucoma More Common in Older, Male and Diabetic Patients with Periodontitis

Among glaucoma patients in this study, 39.5% had periodontitis compared with 22.2% of individuals without glaucoma. Photo: James L. Fanelli, OD. Click image to enlarge. Inflammation plays a major role in periodontitis, and recent findings have suggested that patients with this gum disease may also be at higher risk of glaucoma development and progression. Researchers sought to investigate this matter in a recent study for Journal of Glaucoma and indeed found a strong association between both conditions, especially in patients aged 40 and older, men and those with diabetes.The study included 3,681 individuals in the Korea National Health and Nutrition Examination Survey aged 19 years or older who underwent both dental and ophthalmological examinations that met International Society of Geographical and Epidemiological Ophthalmology criteria. Exclusions included patients with history of ocular surgery (e.g., refractive, cataract, retina) or age-related macular degeneration, as well as those who were pregnant, undergoing orthodontic treatment or missing data.Of all individuals included, 197 (4.6%) had glaucoma and 3,484 (95.4%) did not. Among the glaucoma patients, 80 (39.5%) had periodontitis compared with 892 (22.2%) of those without glaucoma.The authors hypothesized that the correlation between periodontitis and glaucoma, which is consistent with previous studies, could be due to inflammation from periodontitis causing damage to the retinal ganglion cells and optic nerve, eventually leading to glaucomatous change.The advanced glycation end products (AGEs) in diabetic patients may cause toxic effects on neurons by excessively activating microglia of the central nervous system. AGEs also interact with AGE surface receptors to impair the structural and functional activities of lipids and proteins, causing inflammation, the authors explained in their article.“This series of events is associated with inflammation of the central nervous system, inducing a neurodegenerative response in the optic nerve,” the authors write in their Journal of Glaucoma paper. “Moreover, insulin resistance induced by factors such as decreased blood-brain barrier permeability in diabetic patients can exacerbate neuroinflammation and neurodegeneration in the central nervous system.”Given the impact of periodontitis on the central nervous system in relation to the inflammatory response, it is plausible that periodontitis patients with diabetes may be at elevated risk of glaucoma, which the present and several prior analyses have demonstrated.Aging on its own may also cause an inflammatory cascade, the authors explained. Factors such as TNF-α or oxidative stress, which increase in old age, induce necroptosis—a process distinct from apoptosis due to its induction of inflammatory responses—leading to neurodegenerative diseases.“Also, as the retina ages, oxidative stress and lipid peroxidation cause para-inflammation, which can accelerate neurodegenerative changes in the optic nerve and act as a risk factor for glaucoma,” the authors added in their article. “In periodontitis, initial neutrophil infiltration occurs due to pathogens, and then reactive oxygen species are released as antimicrobials. Excessive action of free radicals provokes reactions including lipid peroxidation, which damages proteins and DNA in the host cell.”Periodontitis can regulate proinflammatory cytokines such as TNF-α, IL-1β and IL-6, and these molecules induce systemic inflammation in the central nervous system. “This is expected to have a synergistic effect with aging, which can elevate risk of glaucoma,” the authors wrote.While it’s not clear why periodontitis had a greater impact on glaucoma in males, in this study, males had a higher smoking prevalence than females, and previous studies have showed a high association between smoking and primary open-angle glaucoma, as well as increased intraocular pressure among make smokers and an association between smoking and early-onset open-angle glaucoma.No relationship with glaucoma was found for other oral health factors, such as tooth loss, brushing frequency, use of oral health products or self-awareness of oral health status. This could be because individuals with poorer oral health may engage in more rigorous oral hygiene practices, potentially masking the expected association between oral health behaviors and periodontal disease, and the oral health behaviors may not accurately reflect an individual’s actual oral health status.“This discrepancy between actual oral health status and oral health behaviors could influence the observed lack of association with glaucoma,” the authors noted in their paper. “Moreover, complex factors, such as genetic factors or unmeasured variables not included in the survey, may further complicate this relationship.”The authors concluded that because it was difficult to clearly identify the mechanisms underlying the correlation between periodontitis and glaucoma, further studies are required.Click here for the journal source. Noh JH, Lee MY, Yoo C, et al. Relationship between periodontitis and open-angle glaucoma: the Korea National Health and Nutrition Examination Survey. J Glaucoma. February 1, 2025. [Epub ahead of print.]