Smoking a risk factor for cataract

Smoking appears to contribute to an increased prevalence of cataracts as well as a higher incidence of cataract surgery, according to a study.

Researchers invited 18,055 individuals who were born in the Västra Götaland County, Sweden, to participate in the study. Of these, 9,743 individuals (54 percent) accepted participation and 9,316 (52 percent) remained after exclusion criteria were applied.

The participants completed a questionnaire that included items about eye conditions, smoking, snus, gender, education, asthma, chronic obstructive pulmonary disease, corticosteroid use, diabetes mellitus, weight, and height. Outcomes included self-reported cataract and cataract surgery.

Compared with never having smoked, having ever smoked showed an association with a higher prevalence ratio of self-reported cataract (prevalence ratio [PR], 1.19, 95 percent confidence interval [CI], 1.04–1.35) and cataract surgery (PR, 1.27, 95 percent CI, 1.06–1.53).

Further analysis showed that current smokers were at higher risk of cataract surgery (hazard ratio [HR], 1.34, 95 percent CI, 1.04–1.74), as did former smokers (HR, 1.27, 95 percent CI, 1.03–1.56) relative to never smokers. There was a dose-response association between total years of smoking and the risk of cataract surgery (for every 5 years of smoking: HR, 1.05, 95 percent CI, 1.02–1.08).

Snus use had a null association with the prevalence of cataract or incidence of cataract surgery, except among female current snus users who had a twofold higher risk of cataract surgery compared with never snus users (HR, 2.04, 95 percent CI, 1.16–3.60).