Abstract
Purpose::
Caffeine consumption is positively associated with elevated intraocular pressure (IOP) in open-angle glaucoma patients. In this study, we investigated whether caffeine consumption was associated with an increased risk of primary open-angle glaucoma (POAG).
Methods::
We used 2 large US-based cohorts of women and men respectively, the Nurses' Health Study and Health Professionals Follow-up Study, to form a cohort at risk for POAG. Eligible participants were 40+ years old, did not have POAG at baseline, and reported receiving eye examinations during follow-up. Ultimately 78,712 female nurses and 41,667 male health professionals contributed person-time from 1980-2002 and 1986-2002 respectively. Information on caffeine consumption, potential confounders including smoking history and POAG diagnoses was updated using biennial questionnaires. During follow-up, we identified 856 self-reported POAG cases that were confirmed with medical record review. Cohort-specific and pooled analyses across cohorts were conducted to calculate multivariable rate ratios (RR) of POAG and their 95% confidence intervals [95% CI].
Results::
Although overall, caffeine consumption was not associated with risk of POAG, very high consumption increased risk. Compared with those consuming < 150 mg/day, (about 1 cup of coffee), the pooled RRs were 1.09 [ 0.89-1.34] for consuming 150-299 mg/day, 0.94 [0.75-1.18] for 300-449 mg/day, 1.31 [1.05-1.64] for 450-559 mg/day and 1.16 [0.94, 1.45] for 600 mg+/day [p for linear trend = 0.11]. However, those consuming the most caffeinated coffee (6 or more cups/day) were at 1.71 fold increased risk [95% CI: 1.15-2.55] compared to those not consuming any coffee [p for linear trend = 0.03]. We did not observe associations with tea intake. Associations were more adverse in relation to POAG with elevated IOP.
Conclusions::
Six or more cups of coffee daily were associated with increased risk of POAG; however, lower doses did not appear to influence the risk of POAG.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment