Prospective study of cigarette smoking and the risk of primary open-angle glaucoma.

OBJECTIVE To examine the association between cigarette smoking and incident primary open-angle glaucoma (POAG). METHODS Female nurses and male health professionals were prospectively followed up from 1980 and 1986, respectively, to 1996. Participants were at least 40 years old, were free of diagnosed glaucoma at baseline, and reported being examined by an ophthalmologist or optometrist during follow-up. Smoking history and other POAG risk factors were updated with biennial questionnaires. A total of 450 incident cases of POAG were identified. Both cohort-specific proportional hazards analyses and analyses pooled across cohorts were conducted. RESULTS After controlling for potential risk factors of POAG, including age, hypertension, and African American heritage, neither current smokers (relative risk, 0.85; 95% confidence interval, 0.62-1.18) nor past smokers (relative risk, 0.91; 95% confidence interval, 0.63-1.32) were at greater risk for POAG than those who had never smoked. Heavier smoking did not increase the risk of POAG. A modest inverse association was observed with pack-years of smoking: those with 30 or more pack-years had a 22% reduced risk of POAG (relative risk, 0.78; 95% confidence interval, 0.55-1.11; P for linear trend,.06) than those who had never smoked. CONCLUSION Cigarette smoking is not an important risk factor for POAG.