Smoking cessation and the risk of cataract: a prospective cohort study of cataract extraction among men.

IMPORTANCE Smoking is a risk factor for cataract development, but the effect of smoking cessation on the risk of cataract is uncertain. OBJECTIVE To examine the association between smoking cessation and the risk of cataract extraction. DESIGN, SETTING, AND PARTICIPANTS A total of 44,371 men, participating in the Cohort of Swedish Men, aged 45 to 79 years, who in 1997 completed a self-administered questionnaire on smoking habits and lifestyle factors. The men were followed up from January 1, 1998, through December 31, 2009. The cohort was matched with the Swedish National Day-Surgery Register and local registers of cataract extraction in the study area. MAIN OUTCOMES AND MEASURES Incident cases of age-related cataract extraction. RESULTS During 12 years of follow-up, we identified 5713 incident cases of age-related cataract extraction. Smoking intensity and cumulative dose of smoking were associated with an increased risk of cataract extraction (P for trend <.001). Current smokers of more than 15 cigarettes per day had a 42% increased risk of cataract extraction (rate ratio, 1.42; 95% CI, 1.28-1.58) compared with never smokers after adjustment for age and other potential risk factors. Smoking cessation significantly decreased the risk for cataract extraction with time (P for trend <.001). After more than 20 years since stopping smoking, men with a mean smoking intensity of more than 15 cigarettes per day had a 21% increased risk of cataract extraction (rate ratio, 1.21; 95% CI, 1.06-1.39) compared with never smokers. Among men who smoked 15 cigarettes or less per day, the effect of smoking cessation was observed earlier, but more than 2 decades after smoking cessation, the risk of cataract extraction did not decrease to the level of never smokers (rate ratio, 1.13; 95% CI, 1.04-1.24). CONCLUSIONS AND RELEVANCE Smoking cessation seems to decrease the risk of cataract extraction with time, although the risk persists for decades. The higher the intensity of smoking, the longer it takes for the increased risk to decline. These findings emphasize the importance of early smoking cessation and preferably the avoidance of smoking.