Calcium Channel Blocker Use and Associated Glaucoma and Related Traits Among UK Biobank Participants

Importance Calcium channel blocker (CCB) use has been associated with an increased risk of glaucoma in exploratory studies. Objective To examine the association of systemic CCB use with glaucoma and related traits among UK Biobank participants. Design, Setting, and Participants This population-based cross-sectional study included UK Biobank participants with complete data (2006-2010) for analysis of glaucoma status, intraocular pressure (IOP), and optical coherence tomography (OCT)–derived inner retinal layer thicknesses. Data analysis was conducted in January 2023. Exposure Calcium channel blocker use was assessed in a baseline touchscreen questionnaire and confirmed during an interview led by a trained nurse. Main Outcomes and Measures The primary outcome measures included glaucoma status, corneal-compensated IOP, and 2 OCT-derived inner retinal thickness parameters (macular retinal nerve fiber layer [mRNFL] and macular ganglion cell–inner plexiform layer [mGCIPL] thicknesses). We performed logistic regression and linear regression analyses to test for associations with glaucoma status and IOP and OCT-derived inner retinal thickness parameters, respectively. Results This study included 427 480 adults. Their median age was 58 (IQR, 50-63) years, and more than half (54.1%) were women. There were 33 175 CCB users (7.8%). Participants who had complete data for glaucoma status (n = 427 480), IOP (n = 97 100), and OCT-derived inner retinal layer thicknesses (n = 41 023) were eligible for respective analyses. After adjustment for key sociodemographic, medical, anthropometric, and lifestyle factors, use of CCBs (but not other antihypertensive agents) was associated with greater odds of glaucoma (odds ratio [OR], 1.39 [95% CI, 1.14 to 1.69]; P = .001). Calcium channel blocker use was also associated with thinner mGCIPL (−0.34 μm [95% CI, −0.54 to −0.15 μm]; P = .001) and mRNFL (−0.16 μm [95% CI, −0.30 to −0.02 μm]; P = .03) thicknesses but not IOP (−0.01 mm Hg [95% CI, −0.09 to 0.07 mm Hg]; P = .84). Conclusions and Relevance In this study, an adverse association between CCB use and glaucoma was observed, with CCB users having, on average, 39% higher odds of glaucoma. Calcium channel blocker use was also associated with thinner mGCIPL and mRNFL thicknesses, providing a structural basis that supports the association with glaucoma. The lack of association of CCB use with IOP suggests that an IOP-independent mechanism of glaucomatous neurodegeneration may be involved. Although a causal relationship has not been established, CCB replacement or withdrawal may be considered should glaucoma progress despite optimal care.