Causal associations between smoking and ocular diseases: a Mendelian randomization study

Area of Science:

• Ophthalmology
• Genetics
• Public Health

Background:

• Smoking is a significant global health concern with known links to various diseases.
• The specific causal relationships between smoking and a wide range of ocular diseases remain incompletely understood.
• Mendelian randomization offers a powerful tool to investigate genetic predispositions and causal inference in observational data.

Purpose of the Study:

• To investigate the causal associations between smoking and multiple ocular diseases.
• To leverage genetic variants associated with smoking behavior to infer causality.
• To differentiate between increased and decreased risks for various eye conditions linked to smoking.

Main Methods:

• A two-sample Mendelian randomization (MR) analysis was conducted.
• Publicly available genome-wide association study (GWAS) data were utilized.
• The inverse-variance weighted method, weighted median, and MR-Egger analyses were employed to assess associations and address potential pleiotropy.

Main Results:

• Genetically predicted smoking showed a positive association with increased risk for cataract (OR=1.14), wet age-related macular degeneration (w-AMD) (OR=1.41), diabetic retinopathy (OR=1.06), and optic nerve disorders (OR=1.46).
• Suggestive evidence indicated an inverse association between smoking and myopia (OR=0.75), implying a reduced risk.
• No significant associations were found for glaucoma, allergic conjunctivitis, pterygium, keratitis, scleritis, or episcleritis.

Conclusions:

• Smoking is causally associated with an increased risk of developing cataract, w-AMD, diabetic retinopathy, and optic nerve disorders.
• Smoking may confer a protective effect, potentially reducing the risk of myopia.
• These findings underscore the importance of smoking cessation for preventing serious ocular morbidities.