A PROSPECTIVE-STUDY OF CIGARETTE-SMOKING AND AGE-RELATED MACULAR DEGENERATION IN WOMEN

Objective.-To evaluate the relationship between cigarette smoking acid incidence of age-related macular degeneration (AMD) among women. Desi gn.-Prospective cohort study with 12 years of follow-up (1980 to 1992) , in which information on smoking habits was updated every 2 years. Se tting.-Eleven states throughout the United States. Participants.-A tot al of 31 843 registered nurses enrolled in the Nurses' Health Study wh o were aged 50 to 59 years in 1980 and did not report a diagnosis of c ancer or AMD at the beginning of the study. Additional women entered t he analytic cohort as they reached 50 years of age. Main Outcome Measu re.-Incidence of AMD with visual loss. Results.-During 556 338 person- years of follow-up, 215 women were newly diagnosed as having AMD. Afte r adjusting for other risk factors for AMD, women who currently smoked 25 or more cigarettes per day had a relative risk (RR) of AMD of 2.4 (95% confidence interval [CI], 1.4-4.0) compared with women who never smoked. Past smokers of this amount also had a 2-fold increased risk ( RR=2.0; 95% CI, 1.2-3.4) relative to never smokers. Compared with curr ent smokers, little reduction in risk was suggested even after quittin g smoking for 15 or more years. Risk of AMD also increased with an inc reasing number of pack-years smoked (P for trend <.001); among women w ho smoked for 65 or more pack-years, the risk was 2.4 times the risk o f never smokers (95% CI, 1.5-3.8). Analyses of dry and exudative types of AMD and other alternative definitions of AMD revealed similar resu lts, Conclusions.-Cigarette smoking is an independent and avoidable ri sk factor for AMD among women. Because AMD is the most common cause of severe visual impairment among the elderly and treatment is not avail able or is ineffective for most patients, reducing the risk of this di sease is another important reason to avoid smoking.