Smoking cessation and risk of cataract extraction among US women and men.

Although the observational evidence linking cigarette smoking with risk of senile cataract is well-established, it is unclear whether any benefit is obtained from quitting smoking. Therefore, in this study, the authors examined the association between time since quitting smoking and incidence of cataract extraction in women and men enrolled in the Nurses' Health Study and the Health Professionals Follow-up Study, respectively. There were 4,281 incident physician-confirmed cases of cataract and 1,038,493 accumulated person-years of follow-up. Compared with current smokers, former smokers who had quit smoking 25 or more years previously had a 20% lower risk of cataract extraction after adjustment for age, average number of cigarettes smoked per day, and other potential risk factors (relative risk (RR) = 0.80, 95% confidence interval (CI): 0.71, 0.91). However, risk among past smokers did not decrease to the level seen among never smokers (for never smokers, RR = 0.64, 95% CI: 0.52, 0.79). The observed relation was similar when data were examined by cataract subtype (>25 years since quitting vs. current smoking: primarily nuclear cataract, RR = 0.82, 95% CI: 0.68, 0.97; primarily posterior subcapsular cataract, RR = 0.90, 95% CI: 0.71, 1.13). These findings suggest that any healing from damage due to cigarette smoking occurs at a very modest pace, and they emphasize the importance of never starting to smoke or quitting early in life.