Quitting smoking replenishes body antioxidant status

The effects of smoking on human health are destructive and widespread. Cigarette smoke contains large amounts of free radicals which lead to increased oxidative stress in smokers than in non-smokers. The present study was done to evaluate the extent of oxidative damage caused by smoking. For this purpose 75 subjects were included in the study and divided into three groups: Group A consisted of 25 subjects who were non-smokers and served as controls, Group B (25 subjects) consisted of smokers and in Group C, 25 subjects were included who were smokers earlier but had quitted smoking. Levels of glutathione peroxidase (GPx), catalase (CAT), superoxide dismutase (SOD) and malondialdehyde (MDA) were measured in blood of all the groups and compared. It was observed that the antioxidant enzymes (GPx, CAT and SOD) were decreased (p<0.001) while lipid peroxidation products (MDA) were increased(p<0.001) in smokers as compared to non-smokers. Further it was observed that extent of oxidative damage increased proportionately with increase in amount and duration of smoking but oxidative stress decreased significantly in the subjects who had quitted smoking ascompared to smokers.