PLASMA-FREE RADICAL ACTIVITY AND ANTIOXIDANT VITAMIN LEVELS IN DYSPEPTIC PATIENTS - CORRELATION WITH SMOKING AND HELICOBACTER-PYLORI INFECTION

Background The pathological processes by which Helicobacter pylori inf ection leads to the development of gastroduodenal disease are still in completely understood. Oxygen-derived free radicals are important medi ators of inflammation and potential carcinogens. Furthermore, dietary studies have suggested that antioxidant vitamins may protect against g astric cancer. Objective To determine plasma free radical activity and antioxidant vitamin levels in dyspeptic patients and to correlate the results with H. pylori infection and tobacco smoking. Subjects Forty- three patients undergoing routine endoscopy for investigation of dyspe psia. Methods Plasma free radical activity was determined by measureme nt of thiobarbituric acid-reactive substances (TEARS). Plasma samples were also assayed for the antioxidant vitamins A, C and E, Gastroduode nal biopsies were obtained from all patients for histological examinat ion. Results Plasma TEARS levels were significantly higher in H. pylor i positive versus negative subjects (P < 0.03), smokers versus non-smo kers (P < 0.04) and males versus females (P < 0.01). Multiple regressi on analysis revealed that after correcting for male sex and smoking th ere was no significant association between plasma free radical activit y and H. pylori infection. Smokers had significantly lower levels of p lasma vitamin C than nonsmokers (P < 0.05); no differences were seen i n vitamin A and E levels. Gender and H. pylori infection did not signi ficantly affect plasma antioxidant vitamin levels. Gastroduodenal dise ase was present in all of the smokers compared with 67% of the non-smo kers (P < 0.05); 69% of the smokers were H. pylori positive versus 53% of the non-smokers. Conclusions Tobacco smoking and male sex, both re cognized risk factors for gastroduodenal disease, appear to be the maj or determinants of increased plasma free radical activity in dyspeptic subjects, rather than H. pylori infection. The reason for the higher prevalence of H. pylori infection and gastroduodenal disease in dyspep tic smokers is unclear but may relate to weakened antioxidant defences . (C) 1998 Lippincott-Raven Publishers.