Risk factors for primary open-angle glaucoma and pseudoexfoliative glaucoma in the Thessaloniki eye study

Purpose: To investigate risk factors for primary open-angle glaucoma (POAG) and pseudoexfoliative glaucoma (PEXG) in the Thessaloniki Eye Study.

Design: Cross-sectional, population-based study.

Methods: Randomly selected subjects 60 years of age and older (n=2554) participated in the Thessaloniki Eye Study. Glaucomatous damage and presence of pseudoexfoliation (PEX) were defined according to specific criteria. Open-angle glaucoma (OAG) subjects were compared with nonglaucoma subjects (controls), POAG subjects were compared with controls without PEX, and PEXG subjects were compared with controls with PEX for demographic, lifestyle, ophthalmic, and systemic factors. Factors with P < .2 in the univariate analysis were retained for multivariate analyses.

Results: In multivariate analysis restricted to persons who participated in clinic visits and who had at least 1 phakic eye (n=2078), intraocular pressure (odds ratio [OR], 1.21 per 1 mm Hg; P<.001), PEX (OR, 2.81; P<.001), history of coronary artery bypass or vascular surgery (OR, 1.95; P=.017), and moderate-to-high myopia (≥ -3 diopters; OR, 2.40; P=.009) were associated with higher odds for OAG. In analysis including all clinic visits (n=2261), age became significantly associated (OR, 1.05; P=.004). In multivariate analysis for POAG (n=1840), associations were found for age (OR, 1.04 per year; P=.048), IOP (OR, 1.19 per 1 mm Hg; P<.001), history of coronary artery bypass or vascular surgery (OR, 2.09; P=.01), and history of diabetes treated with insulin (OR, 3.05; P=.045). In multivariate analysis for PEXG (n=238), the latter was associated with increased IOP (OR, 1.25 per 1 mm Hg; P<.001).

Conclusions: IOP was the only factor associated with both POAG and PEXG, whereas moderate-to-high myopia showed borderline significance in both. Vascular systemic diseases and their treatment were associated only with POAG. The implications of these differences for the pathogenesis between the 2 common types of OAG should be explored further.