To evaluate the association between daily coffee consumption and intraocular pressure (IOP) in healthy subjects without glaucoma and the association between daily coffee consumption and history of glaucoma.
A total of 9,850 individuals participated in the first follow-up of the Nagahama Prospective Cohort for Comprehensive Human Bioscience (the Nagahama study) conducted between 2013 to 2016.
All subjects underwent a standardized ophthalmic examination. Self-reporting questionnaires were completed by all participants. Firstly, the association between habitual coffee consumption and intraocular pressure (IOP) among non-glaucoma individuals was evaluated by a multivariable linear regression analysis, adjusting for possible confounders. Secondly, the association between habitual coffee consumption and history of glaucoma was also evaluated using a multivariable logistic regression analysis.
Main Outcome Measures:
The association between habitual coffee consumption and intraocular pressure (IOP) among non-glaucoma individuals.
Of 9,850 participants, 9,418 subjects did not have history of glaucoma. Among these subjects, the average IOP of both eyes was 14.7 ± 2.9 mmHg (mean ± standard deviation). The multivariable regression analysis revealed that habitual coffee consumption was significantly associated with IOP (p < 0.001): the higher the consumption of coffee, the lower the IOP of an individual. The IOP of the group that consumed coffee most frequently (more than or equal to three times a day) was 0.4 mmHg (95% confidence interval: 0.2 to 0.5mmHg) lower than that of the group that consumed coffee least frequently (less than once a day). On the other hand, the logistic regression analysis showed that habitual coffee consumption was not significantly associated with history of glaucoma (P=0.53).
Frequent coffee consumption was associated with a slightly lower IOP in people without glaucoma, but was not associated with a decreased risk of developing glaucoma. Additional experimental studies are needed to examine the effects of coffee on IOP and glaucoma risk.