Researchers investigated the association between dry eye and alcohol consumption and found that alcohol’s effect on dry eye disease (DED) is very sex-specific.

The population-based study included 77,145 participants between the ages of 19 and 94 (59% female) from the Dutch Lifelines cohort. All participants were cross-sectionally assessed for DED with the Women’s Health Study dry eye questionnaire. The researchers assessed alcohol consumption with a self-reporting food frequency questionnaire. Analyses were adjusted for age, sex, BMI, smoking status, education, income and 55 potentially confounding comorbidities.

They found that 30% of participants had symptomatic dry eye, with alcohol significantly increasing the risk in females but not in males. Curiously, the researchers found that increasing alcohol intake had a protective effect on symptomatic dry eye among males. Alcohol had sex-specific effects on all DED outcomes assessed, including symptomatic dry eye, highly symptomatic dry eye, clinical diagnosis and the Women’s Health Study’s definition of dry eye.

“The influence of sex on the association between alcohol use and all outcome measures of dry eye found in this study is particularly intriguing,” the researchers wrote in their paper. “Past studies have not investigated this relationship. Stratification by sex is crucial as alcohol has been found to have different physiological and pathological effects on males and females. In addition, the prevalence, clinical characteristics, pathophysiology and treatment response of dry eye are all well-known to be substantially different in females and males.”

The researchers proposed several mechanisms to explain female response. One theory suggests that differences in sex hormones may play a role. Androgens—more prevalent in males than females—are thought to help maintain ocular surface and adnexal health. Additionally, androgen deficiency has been linked via an autoimmune process to tear deficiency, corneal and conjunctival damage, lacrimal gland inflammation and meibomian gland dysfunction. On the other hand, estrogen stimulates immune responses; its effects on the human ocular surface remain inconclusive.

They concluded that in this large population-based study, alcohol was a risk factor for symptomatic DED only in females. “This adds to the evidence of sex-specific pathophysiological mechanisms of dry eye and illustrates the importance of sex stratification in studies investigating DED,” the researchers wrote. “The mild protective effect of increased alcohol intake in male drinkers is advised to be interpreted with caution, as alcohol’s other health effects might be of greater clinical significance.”