Combined effects of cigarette smoking and alcohol consumption on antioxidant/oxidant balance in age-related macular degeneration

Background and aims: To investigate the single and joint effects of chronic cigarette smoking and alcohol consumption on oxidative stress in age-related macular degeneration (ARMD). Methods: Superoxide dismutase (SOD), glutathione peroxidase (GSHPx), and catalase (CAT) activities; malondialdehyde (MDA) levels; and DNA damage 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 levels and tail parameters (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 had the strongest impact on SOD and GSHPx activities, MDA levels, and amount of DNA damage, whereas in ARMD patients, the combination of smoking and drinking habits was the greatest predictor of oxidative stress. Conclusions: The combination of chronic cigarette smoking and alcohol consumption appears to be an aggravating factor that contribute to serious oxidative imbalance and DNA damage in ARMD. Thus, combined smoking/drinking by persons with this pathological condition should be considered harmful. Identification of factors exacerbating ARMD-associated oxidative stress can facilitate development and adoption of effective preventative measures for this disease.