8-Hyydrodeoxyguanosine (80HdG) was evaluated as a biomarker of a biologically effective does in eight published investigations of occupational exposures to nine potential carcinogens (asbestos, benzene, toluene, chromium, azo-dyes, coal dust, auto exhaust, glassworks, and rubber manufacturing. Study results were summarized in order to 1) assess the sensitivity of 80HdG as a biomarker of oxidative DNA damage, 2) define background levels of 80HdG, 3) determine sample and study variability, and 4) evaluate smoking, gender and age as confounders. Reviewed studies measured either steady-state damage in lymphocytes or repair products of damage appearing in urine; no study examined both. Lymphocyte data were reported as 80HdG/ 10(5) dG and the mean +/- SD of controls was 2.95 +/- 1.3 with an average coefficient of variation (CV) of 31 % in four studies. Units used to express 80HdG excretion in urine varied among the studies. In the two studies that expressed 80HdG in umol/mol creatinine, control values averaged 0.85 and 1.07. The average CV from all urine studies (5) was 38%. All studies reported increased 80HdG relative to controls, but in three cases the increases were not statistically significant. One study detected increased urinary excretion in retired workers with a history of exposure to mining dusts. However, 80HdG appears to be most effective as a biomarker when measured within 24 hrs of exposure. This is consistent with animal studies demonstrating rapid repair of oxidative DNA damage. Five of the studies evaluated smoking as a confounder. Two reported a significant increase in 80HdG in controls who smoked, and one reported that smoking exacerbated the effect of the occupational exposure on 80HdG levels. Urine or lymphocyte 80HdG levels were comparable in control men and women but the response to an occupational exposure and/or smoking was generally greater in women than men. Two of three studies that stratified workers by age found it to be a confounder for the 80HdG adduct.
The Toxicologist. Society of Toxicology 37th Annual Meeting, March 1-5,1998, Seattle, Washington