Measurement of a urinary marker (8-hydroxydeoxy-guanosine, 8-OHdG) of DNA oxidative stress in epidemiological surveys: a pilot study

Background: 8-Hydroxydeoxyguanosine (8-OHdG) is a commonly used marker of DNA oxidative stress in epidemiological studies. The aim of this study was to establish whether the urinary concentration of 8-OHdG varies during the first part of the day, when clinical tests are usually performed, and whether it can therefore be measured without bias in spot urine samples.Material and methods: Spot urine samples were collected using a convenience sample. A linear mixed-effects model for repeated measurements was used to analyze 8-OHdG levels.Results: A significant increasing trend in time in the 8-OHdG concentration was found among smokers, but not in the case of nonsmokers.Conclusions: In epidemiological studies on oxidative stress, all participants should collect their early morning urine specimens - before their first cigarette if they are smokers - to gather information on individual background oxidation levels.