Smoking-induced increasing of oxidative stress in Spanish adults: A urinary biomonitoring study

Oxidative stress (OS) arises from an imbalance between excessive oxidant radicals and insufficient antioxidant defences, leading to damage to lipids, proteins or DNA. OS levels in humans are influenced by health, nutrition, and environmental exposures. A key biomarker of endogenous oxidative DNA damage is 8-hydroxy-2'-deoxyguanosine (8-OHdG). To assess baseline OS, we analysed 8-OHdG levels in first-morning urine samples from adults in the Valencia Community (Spain) using a UHPLC-MS/MS method based on a "dilute-and-shoot" sample preparation. Both 8-OHdG and the nucleoside 2'-dG were quantified in over 92 % of samples, with geometric means of 6.23 and 3.26 µg/L, respectively. Urinary 8-OHdG was directly associated with smoking status, and the levels of urinary metabolites of acrylamide. The oxidation ratio (8-OHdG/2'-dG) also showed correlations with sex and age. The results provide valuable reference data for future epidemiological and toxicological studies and highlight the oxidative stress effects of smoking.