Intensity of smoking and smoking cessation in relation to risk of cataract extraction: a prospective study of women.
The authors investigated the association of smoking and smoking cessation with the incidence of cataract extraction in a population-based prospective cohort study. A total of 34,595 women aged 49-83 years in the Swedish Mammography Cohort were followed from September 1997 through June 2002. Information on smoking, diet, and other lifestyle factors was collected through a self-administered questionnaire. A total of 2,128 cases of age-related cataract extraction were identified. Relative risks were estimated as rate ratios using Cox proportional hazards models. The authors observed a significant dose-response association between intensity of smoking and risk of cataract extraction (among current smokers, p for trend = 0.02; among past smokers, p for trend = 0.0002). After cessation of smoking, the risk decreased with time. Among women with a moderate lifetime smoking intensity (6-10 cigarettes/day), the relative risk was not significantly different from the risk among never smokers 10 years after smoking cessation. Among women who had smoked more intensively (>10 cigarettes/day), after 20 years of nonsmoking the increased risk became small and no longer statistically significant in comparison with never smokers (for trend over time, p < 0.0001). This prospective study confirmed smoking as a risk factor for cataract, with a dose response for smoking intensity. Smoking cessation predicts reduced risk over time, but a longer period of time is needed with a higher smoking intensity.
Lindblad
Birgitta Ejdervik
BE
Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden. birgitta.ejdervik.lindblad@swipnet.se
Håkansson
Niclas
N
Svensson
Hanna
H
Philipson
Bo
B
Wolk
Alicja
A
D000368:Aged; D000369:Aged, 80 and over; D002387:Cataract Extraction / Q000706:statistics & numerical data*; D015331:Cohort Studies; D016001:Confidence Intervals; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D015994:Incidence; D008875:Middle Aged; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology; D016540:Smoking Cessation / Q000706:statistics & numerical data*; D011795:Surveys and Questionnaires; D013548:Sweden / Q000453:epidemiology