The association between alcohol and glaucoma was remarkable at higher drinking frequency per week. However, the effect of the average daily drink intake was not statistically significant. Photo: Stanislav Ivanitskiy on Unsplash. Click image to enlarge.

Understanding the effects of alcohol consumption on glaucoma could provide evidence for clinical guidelines in the condition’s management. Researchers in Japan examined the association between alcohol exposure and glaucoma prevalence using data from a nationwide, multicenter hospital-based inpatient registry database. The odds ratios (ORs) for glaucoma prevalence were more significant for heavy alcohol consumption. These results were particularly robust among men.

This study evaluated 3,207 cases with glaucoma and 3,207 matched controls. Patients over 40 years of age were included from 1,693,611 patients admitted to 34 hospitals in Japan. Detailed alcohol consumption patterns (drinking frequency, average daily drinks and total lifetime drinks) were obtained, as well as various confounding factors, including smoking history and lifestyle-related comorbidities. Drinking frequency was categorized into four groups (never, former, a few days/week and almost every day/week).

Drinking frequency showed an association with glaucoma for “a few days/week” (OR=1.19) and “almost every day/week” (OR=1.40). Average daily drinks showed an association for “>zero to two drinks/day” (OR=1.16). Total lifetime drinks showed an association for “>60 to 90 drink-year” (OR=1.23) and “>90 drink-year” (OR=1.23).

Additional analyses were conducted separately for men and women. Among men, drinking frequencies of “a few days/week” and “almost every day/week,” average daily drinks of “>zero to two drinks/day” and “>two to four drinks/day,” and total lifetime drinks of “>60 to 90 drink-year” and “>90 drink-year” had an association with glaucoma. Conversely, among women, neither drinking frequency, average daily drinks, nor total lifetime drinks were associated.

“In this study, the results for men alone were more robust than those for both sexes, with the ORs for glaucoma prevalence being more significant,” the researchers wrote in their paper. “In contrast, the results in women were not statistically significant.”

They did note that the alcohol consumption reported in surveys tends to be less than actual consumption, introducing a potential information bias that could skew the results. Additionally, they proposed that sample size bias by alcohol consumption levels in women may have led to the differences in the results between sex. Interestingly, the team also brought up that the reason why their study showed a relatively strong association between alcohol consumption and glaucoma could be related to the fact that Asians, including the Japanese, are susceptible to alcohol.

“We hypothesized that there would be differences among races in their ability to metabolize alcohol,” the researchers wrote.

They acknowledged the possible impact of the metabolite of alcohol, acetaldehyde, that some Asians are affected by when metabolizing. “If acetaldehyde affects glaucoma, it is reasonable that alcohol consumption is strongly associated with glaucoma in Asian populations that metabolize acetaldehyde less effectively,” the authors of the paper wrote.

Data not included in this study that the researchers believe could help improve findings include data on diet or exercise, IOP or visual field testing as well as the types of alcohol consumed.

“The results of this study will encourage further research on how drinking habits affect glaucoma incidence and progression,” they concluded. “We believe the current study is a crucial step toward elucidating the epidemiology and pathogenesis of glaucoma.”