8-Hydroxydeoxyguanosine in DNA from leukocytes of healthy adults: relationship with cigarette smoking, environmental tobacco smoke, alcohol and coffee consumption

8-Hydroxydeoxyguanosine (8-OHdG) has been widely used as a biomarker of oxi dative DNA damage in both animal and human studies. However, controversial data exist on the relationship between 8-OHdG formation and age, sex and to bacco smoking in humans, while few or no data are available on other exposu res such as environmental tobacco smoke, alcohol, coffee and tea consumptio n. We investigated the level of 8-OHdG in DNA from peripheral leukocytes am ong 102 healthy adults living in Brescia province, North Italy, aged 25-45 (mean: 35.2 years), of which 51 were males. 8-OHdG levels expressed as a ra tio to total deoxyguanosine (8-OHdG/10(6) dG) in DNA showed wide interindiv idual variation, the highest value (63.8) being 6.2-fold greater than the l owest (10.3). Current smokers showed lower mean 8-OHdG values than subjects who never smoked (79.3 and 34.0, respectively, p < 0.05), and an inverse r elationship was found between 8-OHdG and lifetime smoking, which was indepe ndent of age, sex and body mass index. An inverse relationship was also fou nd with coffee drinking while no association was observed with alcohol and tea consumption, exposure to environmental tobacco smoke and use of vitamin s in all subjects, and with use of oral contraceptives in females. The inve rse relationship between smoking status and 8-OHdG levels could be explaine d by the presence of efficient repair processes for the oxidative damage in duced by smoking. In this study, the smokers were relatively young (77% wer e less than 40 years) and only 7% smoked 30 or more cigarettes a day. In co nclusion, it would appear that 8-OHdG levels in leukocytes may not provide a sensitive marker of exposure to tobacco smoking. (C) 1999 Elsevier Scienc e B.V. All rights reserved.