Repeated measures of coffee and tea consumption in relation to open‐angle glaucoma risk and intraocular pressure regulation

Purpose: Previous studies suggest that caffeine is involved in the pathophysiology of open-angle glaucoma (OAG) and the regulation of the intraocular pressure (IOP). However, prospective studies with availability of repeated measures on coffee and tea consumption are limited. The purpose of this study is to identify if and to what extent coffee and tea consumption over time is associated with OAG risk and IOP regulation.
Methods: Participants of the Rotterdam Study, a longitudinal population-based cohort study, were regularly monitored for OAG. Data on coffee and tea consumption were collected using questionnaires. At baseline, 9731 participants were free of OAG; 8522 were assessed at a second visit; 3916 continued to a third visit; and 1297 participants were seen a fourth time. Over time, 201 participants developed OAG. The association between coffee and tea consumption and OAG or IOP was analysed using generalized estimating equations, adjusted for age, sex, body mass index, total energy intake, alcohol consumption, and follow-up time. Additional adjustment for lifestyle factors (physical activity, diet quality, and smoking status) or comorbidities (diabetes mellitus and hypertension) was also performed.
Results: Neither coffee (Odds ratio [OR] with corresponding 95% confidence interval [95% CI]: 1.06 [0.95; 1.17] per cup [125 g] increase) nor tea (OR [95% CI]: 1.01 [0.92; 1.10] per cup [150 g] increase) consumption was associated with OAG risk. Coffee consumption was significantly associated with lower IOP (beta [95% CI]: −0.03 [−0.06; −0.01] per cup increase). Participants drinking the most coffee (4 cups or more per day) had the largest IOP reduction (beta [95% CI]: −0.28 [−0.54; −0.03]) as compared to non-users (p-tend = 0.02). We also found a significant association between tea consumption and lower IOP (beta [95% CI]: −0.05 [−0.08; −0.03] per cup increase). Highest tea consumption (3 cups or more per day) was associated with the largest IOP reduction (beta [95% CI]: −0.26 [−0.40; −0.07]) as compared to non-users (p-tend Conclusions: Although coffee and tea consumption were not associated with OAG risk, both were associated with significantly lower IOP. Our findings confirm earlier reported associations between coffee and tea consumption and IOP.