Metabolic syndrome as an independent risk factor for glaucoma: a nationally representative study

BACKGROUND: Central insulin resistance contributes to glaucoma development. Given the close association between metabolic syndrome MetS and insulin resistance, this study aimed to determine whether MetS is associated with glaucoma risk. METHODS: We analyzed data from 11,499 adults aged ≥ 19 years in the 2019–2021 Korean National Health and Nutrition Examination Survey and applied sampling weights to represent the general Korean population. Participants were classified into groups with or without MetS. Ocular hypertension (HTN) was defined as intraocular pressure > 21 mmHg. Primary open-angle glaucoma (POAG) was diagnosed based on the results of a visual field test and optical coherence tomography using the criteria published by the International Society for Geographic and Epidemiological Ophthalmology. We further divided POAG into normal tension (NTG) and POAG with ocular HTN. A spline curve was drawn to determine the dose–response relationship between the number of MetS components and risk of POAG. Odds ratios (ORs) with 95% confidence interval (CI) for POAG according to MetS status were estimated using weighted logistic regression analyses. RESULTS: The prevalence of POAG was 5.7% and 3.5%, respectively, in groups with and without MetS. We identified a dose–response relationship between the number of MetS components and risk of POAG. Unadjusted ORs (95% CI) for POAG in the group with MetS was 1.85 (1.52–2.25), compared with those without MetS. The trends persisted in adjusted models. The fully-adjusted OR (95% CI) for POAG was 1.47 (1.04–2.09) in the group with MetS. Subgroup analysis revealed that a significant relationship remained only in the NTG group (fully adjusted OR, 1.50; 95% CI 1.05–2.15). CONCLUSIONS: A comprehensive ophthalmological assessment should be considered for persons with MetS who are at increased risk of POAG, particularly NTG. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13098-023-01151-5.