Urinary Excretion of an Oxidative Stress Marker, 8‐hydroxyguanine (8‐OH‐Gua), among Nickel‐cadmium Battery Workers

Urinary Excretion of an Oxidative Stress Marker, 8‐hydroxyguanine (8‐OH‐Gua), among Nickel‐cadmium Battery Workers: Noriyuki Y oshioka , et al . Department of Preventive Medicine and Public Health, School of Medicine, Keio University —The relationship between oxidative stress and carcinogenic metals including nickel and cadmium is a matter of interest. To assess the oxidative stress status of workers exposed to nickel and cadmium simultaneously, we determined urinary excretion of 8‐hydroxyguanine (8‐OH‐Gua), a urinary oxidative stress marker. Our subjects were 66 (64 males and 2 females) nickel‐cadmium battery workers. Spot urine and blood samples were collected. The levels of cadmium in blood (Cd‐B) and nickel in urine (Ni‐U) were determined by graphite furnace atomic absorption spectrophotometry. 8‐OH‐Gua in urine was analyzed using a high performance liquid chromatography‐electrochemical detector (HPLC‐ECD) system. Data on age, sex, duration of present work and smoking status were also obtained from each subject. Creatinine‐adjusted 8‐OH‐Gua was significantly correlated with age, Ni‐U and Cd‐B in univariate analysis, while multivariate analysis revealed that Ni‐U and Cd‐B were significant independent variables and that these two biological exposure indices were positively correlated with 8‐OH‐Gua. The data were also analyzed in the context of mixture toxicity. The subjects were divided into groups based on median level of Ni‐U and Cd‐B (2.86 μ g/g creatinine and 0.23 μ g/d l , respectively). Workers with high Ni‐U/high Cd‐B (Group IV) had the highest levels of 8‐OH‐Gua levels (GM (GSD), 21.7(2.0)), followed by those with high Ni‐U/low Cd‐B (11.5(1.6) Group III), those with low Ni‐U/high Cd‐B (8.9(1.9) Group II), and those with low Ni‐U/low Cd‐B (8.5(1.5) Group I). The p values of Students' t ‐tests between Group I and Group II, III and IV were 0.847, 0.050 and <0.001, respectively. The combined effect of Cd and Ni on the urinary excretion of 8‐OH‐Gua departed from additivity.