Life Style and Urinary 8‐Hydroxydeoxyguanosine, a Marker of Oxidative DNA Damage: Effects of Exercise, Working Conditions, Meat Intake, Body Mass Index, and Smoking

The urinary levels of 8‐hydroxydeoxyguanosine (8‐OH‐dG), a marker of oxidative DNA damage, of 318 healthy men aged 18‐58 were measured with high resolution by a newly developed automated high‐pressure liquid chromatography (HPLC) system coupled to an electrochemical detector (ECD). The mean 8‐OH‐dG level (μMg/g creatinine) was 4.12±1.73 (SD). An eleven‐fold inter‐individual variation was observed. The accuracy of the measurement estimated from the recovery of an added 8‐OH‐dG standard was 90‐98%. By univariate analysis, it was found that moderate physical exercise (P=0.0023) and high body mass index (BMI) (P=0.0032) reduced the 8‐OH‐dG level, while physical labor (P=0.0097), smoking (P=0.032), and low meat intake (less than once/ week) (P=0.041) increased its level. Based on a multi‐regression analysis of the log‐transformed values, moderate physical exercise (P=0.0039), high BMI (P=0.0099), and age (P=0.021) showed significant reducing effects on the 8‐OH‐dG level, while low meat intake (P=0.010), smoking (P=0.013), and day‐night shift work (P=0.044) increased its level. These results suggest that many types of life‐style factors that either generate or scavenge oxygen radicals may affect the level of oxidative DNA damage of each individual.