Autoantibody against oxidized low-density lipoproteins may be enhanced by cigarette smoking

A total of 59 healthy male subjects (32 smokers and 27 nonsmokers) who had no reported systemic disease and did not take alcohol and vitamin supplemen tation were included. The levels of autoantibody to oxidized low-density li poproteins (ox-LDL) in smokers and age-matched nonsmokers were compared. Th e plasma levels of antioxidants that can affect the formation of ox-LDL wer e also measured, and correlation analyses between anti ox-LDL IgG and plasm a antioxidants, controlling for age and body mass index (BMI), were perform ed. Plasma alpha-tocopherol and uric acid concentrations of nonsmokers (2.7 8 +/- 1.09 mu g/mg total lipid and 6.96 +/- 1.69 mg/dl, respectively) were significantly higher than those of smokers (1.68 +/- 0.48 mu g/mg total lip id and 6.15 +/- 1.14 mg/dl, respectively) (P < 0.05). Although plasma ascor bate and retinol levels were not significantly different between smokers an d nonsmokers, smokers older than 45 years old had significantly lower plasm a ascorbate levels (0.32 +/- 0.17 mg/dl) than age-matched nonsmokers (0.53 +/- 0.14 mg/dl) (P = 0.036). Higher level of plasma anti ox-LDL Ige was not ed in the group of smokers compared with nonsmokers (515 +/- 409 mU/ml vs. 407 +/- 268 mU/ml, respectively) under the statistic method of Chi-Square t est (P = 0.049). A significant negative correlation was found between plasm a anti ox-LDL IgG and alpha-tocopherol in the combined population as well a s in the smoker group (r = - 0.26, p = 0.047; r = - 0.48, p = 0.006; respec tively). However, there was no correlation between plasma anti ox-LDL IgG a nd the levels of other antioxidants. These results suggest that reduced con centrations of alpha-tocopherol are associated with cigarette smoking. The significantly negative correlation between plasma anti ox-LDL IgG and alpha -tocopherol in the entire study population as well as in the smoker group s uggests that plasma alpha-tocopherol may be partially effective if not tota lly at protecting LDL from oxidative damage caused by cigarette smoking and dietary supplementation with alpha-tocopherol may provide a protective eff ect against LDL oxidation, especially in smokers. (C) 2127 Elsevier Science Ireland Ltd. All rights reserved.