Abstract
Abstract: :
Purpose:Only a few risk factors have been consistently shown to be related to age-related macular degeneration (AMD), including cigarette smoking and increasing age. Except for the effect of vitamin/mineral supplements, little is known about why some individuals with mild to moderate stages of AMD progress to the more advanced stages associated with visual loss. The Progression of Age-Related Macular Degeneration Study is a longitudinal study designed to measure multiple risk factors for the onset and progression of advanced AMD. Methods:A total of 283 individuals were included in these analyses, 110 males and 173 females. All participants were at least 60 years of age at baseline, with no reported history of cancer. Average follow-up time was 4.8 years. The total number of person-years of follow-up for males and females was 567.3 and 788.9, respectively. A five-grade classification scale of AMD was used. Progression of AMD was defined as either eye progressing from a grade of less than 4 (extensive small or large drusen) to grades 4 (geographic atrophy) and 5 (neovascular AMD), or progressing from grade 4 to grade 5, at any follow-up visit. We adjusted for age, sex, systolic blood pressure, smoking status (current, past, never), systemic hypertension, baseline AMD grade, body mass index at baseline, and dietary factors at baseline including dietary calorie-adjusted carotenoid intake, calories (continuous), and alcohol intake. Cox proportional models were used to assess increased risk of advanced AMD according to risk factor exposure. Results:The overall conversion rate was 27.9%. Among females, current smokers had a 3.5 fold increased risk [RR 3.5 95%CI 1.4,8.8 (p =.007)] of progressing to advanced AMD and past smokers had 1.3 fold increased risk [RR 1.3 95% CI 0.7,2.2 (p=.45)], although the latter finding was not statistically significant. Among males, similar trends were seen for current [RR 1.4 95%CI 0.3,7.3(p=.71)] and past [RR 1.4 95%CI 0.5,3.4(p=.51)] smokers, compared to never smokers, however these results were not statistically significant. Conclusion:Smoking increases risk of progression to advanced AMD among women. In addition to the known effects of smoking on onset of AMD, these results regarding progression add new and valuable insights regarding the management of AMD.
Keywords: 308 age-related macular degeneration • 355 clinical (human) or epidemiologic studies: risk factor assessment