Cannabis Use Linked to Earlier Cataract Development in UK Biobank Study | Research

The takeaway

People who used cannabis 11-100+ times developed cataracts 4-5 years younger than non-users, independent of cigarette smoking.

Long-term cannabis users, ophthalmology researchers

4-5 years earlier cataract diagnosis

What the researchers found

Cannabis users (11-100 times) were diagnosed with cataracts 4-5 years earlier than non-users. This association was independent of cigarette pack-years (P<0.001 for cannabis, P=0.008 for independence from cigarettes). However, cannabis use did not increase the overall odds of developing cataracts.

Why it matters

Cannabis smoke contains many of the same toxic compounds as tobacco smoke. While cigarette smoking is a known cataract risk factor, less was known about cannabis. This study suggests cannabis may accelerate cataract timing without increasing overall risk.

The numbers in context

28,432 subjects with cataracts; 4-5 years earlier diagnosis; cannabis effect P<0.001; cigarette OR 1.2 for cataract; cannabis OR not significant for overall cataract risk

How the study worked

Analysis of 28,432 UK Biobank subjects with cataracts, using propensity score matching with cigarette smoking and age as covariates. Cannabis use frequency was the indicator variable.

What this study cannot tell us

Self-reported cannabis use in UK Biobank. Cannot account for method of consumption (smoked vs other). Association does not prove causation.

How to read the evidence

Large cohort with propensity score matching and controls for cigarette smoking, but observational design with self-reported cannabis use.

When this study was published

Published in 2022

The bigger picture

As cannabis use becomes more common, understanding its effects on eye health beyond glaucoma becomes important. This large cohort study adds cataracts to the list of conditions where cannabis may play a role.

Questions still open

Would non-smoked cannabis (edibles, oils) show the same association with earlier cataracts? Is the mechanism related to smoke exposure specifically or to cannabinoid effects on the lens?

Common questions

Does cannabis cause cataracts?

This study found cannabis users developed cataracts earlier but did not have higher overall odds of getting cataracts. The association was independent of cigarette smoking.

How much earlier did cannabis users develop cataracts?

Users who consumed cannabis 11-100+ times were diagnosed with cataracts 4-5 years earlier than those who never used cannabis.

Read the original research

Marijuana smoking and cataract.

Journal francais d'ophtalmologie, 45(3), 267-271

View on PubMed ↗Publisher’s paper ↗

Citation

Lehrer, S; Rheinstein, P H. (2022). Marijuana smoking and cataract.. Journal francais d'ophtalmologie, 45(3), 267-271. https://doi.org/10.1016/j.jfo.2021.12.008