Alcohol Intake and Cataract Development
By Lynda Seminara
Selected By: Stephen D. McLeod, MD
Ophthalmology, June 2021
Studies of alcohol’s effect on cataract formation have been fraught with design flaws and conflicting conclusions. Chua et al. conducted a large longitudinal study to better understand the possible relationship. They observed a strong correlation between levels of alcohol use currently categorized as “safe” and lower likelihood of cataract, with wine being the most beneficial beverage. Cataract surgery was more common among nondrinkers and those who drank heavily.
The study population was derived from two large registries (UK Biobank and EPIC-Norfolk) of patients who had cataract surgery and agreed to provide detailed lifestyle information. The researchers used Cox proportional hazards models to explore possible links between cataract surgery and the amount and type of alcohol consumed. The categories of alcohol consumption were none, <1-3 times/month, 1-2 times/week, 3-4 times/week, and daily or near-daily. Analyses were adjusted for age, sex, ethnicity, social support, body mass index, smoking status, and diabetes. The primary outcome was incident cataract surgery.
Altogether, there were 23,584 incident cases of cataract surgery. Mean follow-up time was 95 months and 193 months for the UK Biobank and EPIC-Norfolk cohorts, respectively. Compared with nondrinkers, drinkers in both cohorts were less likely to undergo cataract surgery. After adjustment for covariates, the hazard ratio was 0.89 for the UK Biobank cohort and 0.90 for the EPIC-Norfolk group. Among alcohol users in EPIC-Norfolk, greater consumption correlated with reduced risk of cataract surgery (p < .001), whereas the UK Biobank data showed a U-shaped curve, indicating elevated risk for those on either end of the spectrum of alcohol intake. Compared with abstinence from alcohol, moderate drinking (1-4 times/week) was associated with a 6%-7% lower risk of cataract surgery. Relative to moderate drinkers, heavy drinkers had a 5%-6% higher risk of cataract surgery.
Red wine was found to confer the greatest protective benefit, possibly because of the concentration of polyphenol antioxidants in the skin of red grapes. The highest level of safe wine consumption reduced the risk of cataract surgery by 23% (EPIC-Norfolk) and 14% (UK Biobank).
The authors cautioned that their findings signify a correlational rather than a causal connection. Moreover, they noted that alcohol consumption raises the risk of many diseases that are serious and chronic.
The original article can be found here.