Alcohol Consumption Worsens Glaucoma-Related Traits

Alcohol intake has a consistent and adverse association with glaucoma and related traits, and at levels below current UK and US guidelines, according to a study published in Ophthalmology Glaucoma.

Researchers conducted a cross-sectional analysis to examine the associations of alcohol consumption with glaucoma and related traits, and to assess whether a genetic predisposition to glaucoma modifies any associations. The study included UK Biobank participants with data on intraocular pressure (IOP, n=109,097), optical coherence tomography (OCT) derived macular inner retinal layer thickness measures (n=46,236), and glaucoma status (n=173,407). The researchers categorized participants according to self-reported drinking behaviors, deriving quantitative estimates of alcohol intake from touchscreen questionnaires and food consumption tables. 

With 2-step analysis, the researchers compared categories of alcohol consumption and subsequently assessed participants for a dose-response effect in participants who drank regularly only. The researchers examined associations using multivariable linear, logistic, and restricted cubic spline (RCS) regression, adjusted for key sociodemographic, medical, anthropometric and lifestyle factors. Outcome measures included IOP, macular retinal nerve fiber layer (mRNFL) thickness, macular ganglion cell-inner plexiform layer (mGCIPL) thickness, and prevalent glaucoma. 

The study found that patients who drank regularly had higher IOPs (+0.17 mm Hg; P <.001 and thinner mGCIPL (-0.17 µm; P =.049) compared with those who drank infrequently; those who identified as ‘former drinkers’ also had a higher prevalence of glaucoma (OR 1.53; P =.002). Alcohol intake was adversely associated with all outcomes in a dose-dependent manner in participants who drank regularly (all P <.001). For mRNFL and mGCIPL thickness, nonlinear associations with apparent threshold effects at approximately 50 grams per week were suggested by RCS regression analyses. Participants at higher genetic susceptibility to glaucoma had significantly stronger alcohol-IOP associations (P <.001). Evidence for a causal association with mGCIPL thickness was provided by MR analyses. 

The current evidence base consists mostly of nonsignificant or inconsistent research results showing these associations, according to the study. Therefore, the researchers highlighted the significance of this study due to its specific design to explore the relationships between alcohol consumption, IOP, and open-angle glaucoma. 

“While causality cannot be definitively inferred, these results are supportive of a true underlying association, rather than a case of residual confounding or reverse causality,” the researchers explain.

Study limitations include possible confounding due to lower alcohol consumption in participants than in the general population; and possible confounding due to the method of self-report around alcohol intake.

Disclosure: Some study authors declared affiliations with the biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.