RESUMO
Objective: Tobacco has a time dependent effect on the antioxidant system of the body. This study was designed to determine and compare alteration in levels of erythrocyte superoxide dismutase (SOD), glutathione peroxidase (GPx) and catalase (CAT) in blood subgroups of tobacco smokers and chewers with controls. Materials and Methods: Blood samples were collected from 30 tobacco smokers (> 20 cigarettes daily), 30 tobacco chewers (> 10 packets gutka daily) and 30 controls. These groups were further divided into three subgroups (n=10) based on duration of habit (<5 yrs, 5-10 yrs, >10 yrs). The level of erythrocyte SOD, GPx and CAT were measured using standard procedures. Results: The SOD and CAT levels were significantly decreased in all subgroups of smokers and chewers whereas GPx level was significantly increased. Positive correlation was observed between SOD, GPx and CAT levels with change in duration of habit in all subgroups. No significant difference observed in SOD and CAT activity between tobacco smokers and chewers. Conclusions: The findings suggested that antioxidative enzyme activities have significant correlation with change in the duration of tobacco use. Measurement of markers of free radical activity might be useful for estimating the level of oxidative stress caused by tobacco use.