Impact of smoking, alcohol consumption and aging on antioxidant/pro-oxidant balance in age-related macular degeneration

Background: Oxidative stress, inflammation, and genetics are thought to contribute to the development of age-related macular degeneration (ARMD), the most common cause of blindness in the elderly. The aim of this study was to determine whether smoking, alcohol consumption and aging, which constitute the main exogenous sources of reactive oxygen species (ROS), affect the balance between oxidant production and antioxidant levels in ARMD. Methods: Superoxide dismutase (SOD), glutathione peroxidase (GSHPx), and catalase (CAT) activities as well as malondialdehyde (MDA), protein carbonyl (PC), 8-hydroxy-29-deoxyguanosine (8-OhdG) and total oxidation status (TOS) levels, were measured in patients with early ARMD (n=211) and late ARMD (n=205), and control persons (n=262). Results: When compared with healthy controls, early- and late- ARMD patients showed significant decreases in the activities of SOD and GSHPx, but not CAT, along with marked enhancements of MDA, PC, TOS and 8-OhdG (P < 0.01). No notable differences were observed in the early- versus the late-ARMD group for each of the above-mentioned dependent variables. Multiple regression analysis revealed that in healthy subjects chronic smoking and aging had the strongest impact on oxidative stress parameters, whereas in ARMD patients, the combination of smoking, drinking, and aging was the greatest predictor of oxidative DNA, protein and lipid damage. Conclusions: Cigarette smoking, alcohol consumption and aging could be aggravating factors contributing to serious redox imbalance and oxidative damage in ARMD. Identification of factors exacerbating ARMD-associated oxidative stress can facilitate development and adoption of effective preventative measures for this disease.