Institute of Epidemiology and Social Medicine, Clinical Epidemiology Section, University of Muenster, Muenster, Germany. neuner@uni-muenster.de
PURPOSE: To prospectively evaluate the impact of homozygosity in the A69S-SNP of the LOC387715-gene, smoking history, and their interaction on visual functional status (v-FS) in age-related macular degeneration (AMD). METHODS: The Muenster Aging and Retina Study (MARS) cohort (n = 656; 58.8% women, mean age 70.2 years) was followed over a mean of 2.5 years. AMD-status, genotype and smoking history were assessed at baseline. V-FS [from 0 (low) to 100 (unimpaired) points in general-, near- and far-vision], were AMD-status assessed at baseline and at follow-up. Linear models with stepwise adjustments for covariates were used to analyze decline of v-FS over time. RESULTS: In initial models, homozygosity for the A69S-variant was negatively associated with all three dimensions of the v-FS. After including smoking history, ever smoking was negatively associated with declines in near and far vision (-4.82 and -5.12 points, respectively; each p < 0.05). In smokers homozygous for the A69S-variant the number of cigarettes smoked per day (smoking intensity) was negatively associated with all three dimensions of the v-FS (interaction term each p < 0.05). Time since smoking cessation in former smokers protected against declines in near and far vision. These effects were independent of the AMD-status at baseline. CONCLUSIONS: The interaction of homozygosity for the A69S-variant and smoking intensity had a negative impact on general-, near-, and far visual functional status independent of AMD-status. Quitting smoking seemed to have a time-dependent protective effect on near and far vision.