8 Hydroxydeoxyguanosine as a biomarker of workplace exposures

Our plain-English summary of 8 Hydroxydeoxyguanosine as a biomarker of workplace exposures, by M. Toraason (Biomarkers, 1999).

The study

• Author: M. Toraason
• Journal: Biomarkers
• Published: 1999;4(1):3-26
• Cited by: 30 articles, as counted by NIH iCite
• Read it: PubMed · Publisher

Abstract

To date, the 8-hydroxydeoxyguanosine (8OHdG) DNA adduct has been used as a biomarker in 11 occupational health studies examining the potential for ten different workplace exposures to cause oxidative DNA damage. Exposures examined include asbestos, azo-dyes, benzene, chromium, coal dust, glassworks, rubber manufacturing, styrene, toluene and environmental tobacco smoke (ETS). Experimental designs that applied 8OHdG as biomarker varied dramatically among the studies. For example, one study detected increased urinary excretion in retired workers with a history of exposure to mining dusts, while a study of workers exposed to benzene showed that the pattern of urinary excretion of 8OHdG varied over a 24h period following exposure. All but one study reported increased 8OHdG relative to controls, but in three cases the increases were not statistically significant. Only one study demonstrated a dose-response relationship between a chemical exposure (benzene) in the workplace and elevated 8OHdG. In most cases, exposure data were lacking and the elevated 8OHdG could only be considered to be associated with a generalized job category. Numerous animal and human studies have demonstrated an effect of tobacco smoke on 8OHdG, including a study of ETS in the workplace. In the majority of occupational studies, however, smoking was found not to be a confounding variable. 8OHdG levels tended to be higher in women than men as did the response to an occupational exposure and/or smoking. Two of three studies that stratified workers by age found it to be a confounder for the 8OHdG adduct, but the relationship between age and 8OHdG was non-linear. Only one study considered the impact of dietary supplements on 8OHdG levels in workers despite the fact that diet can have a marked effect on an individual's response to oxidative stress. It is premature to consider 8OHdG as biomarker that can be used for decision making or for regulatory purposes. Nonetheless, these studies demonstrate that with additional characterization of the role 8OHdG plays in the exposure-disease continuum it may well serve as a powerful biomonitoring toolin the future.

In plain English

This article was a review of 11 workplace studies. The author, at the US National Institute for Occupational Safety and Health, looked at studies that measured 8-hydroxydeoxyguanosine (8OHdG), a marker of oxidative DNA damage, in workers' urine or blood. The exposures covered were asbestos, azo-dyes, benzene, chromium, coal dust, glass work, rubber work, styrene, toluene and environmental tobacco smoke.

Three of the reviewed studies involved asbestos. In Tagesson et al. (1993), 30 workers exposed mainly to chrysotile had significantly higher urinary 8OHdG than 41 controls (mean 1.40 versus 1.07 micromol per mol creatinine). Hanaoka et al. (1993) found no significant difference between retired dockyard workers with asbestosis and controls. Takahashi et al. (1997) found significantly higher 8OHdG in white blood cells of asbestos-factory workers with asbestosis.

Across all 11 studies, all but one reported higher 8OHdG than controls, but three of those increases were not statistically significant. The author noted that most studies lacked exposure data. The author concluded it was premature to use 8OHdG for decision making or regulation.

We wrote this plain-English summary from the full article with the help of AI, and a second AI model checked each sentence against the article. It is not the authors' wording; the abstract and the article are their own account.

What the study did and found

• Design: Review of published occupational studies using 8OHdG as a biomarker of oxidative DNA damage
• Who was studied: 11 occupational health studies of workers with ten different workplace exposures, all measuring 8OHdG by HPLC-EC in urine or blood cells
• Exposure: Asbestos, azo-dyes, benzene, chromium, coal dust, glassworks, rubber manufacturing, styrene, toluene and environmental tobacco smoke. In the Tagesson et al. (1993) asbestos group, exposure was mainly to chrysotile at levels not exceeding 1 mg per cubic metre, in making fabrics, ropes and asbestos packings.
• Main results:
  • Tagesson et al. (1993): urinary 8OHdG in 30 asbestos-exposed workers was significantly greater than in 41 controls (table: 1.40 versus 1.07 micromol per mol creatinine, +31%, P less than 0.01)
  • Hanaoka et al. (1993): no significant difference between controls and retired dockyard workers with asbestosis (table: 1.0 in 7 controls versus 1.03 in 6 exposed, lymphocytes)
  • Takahashi et al. (1997): 8OHdG in white blood cell DNA was significantly higher in working and retired asbestos-factory workers with asbestosis (table: 2.39 in 20 exposed versus 1.78 in 19 controls, +34%, P less than 0.05)
  • Across the reviewed studies, all but one reported increased 8OHdG relative to controls; in three cases the increases were not statistically significant
  • In Tagesson et al. (1993), asbestos exposure was associated with significantly increased urinary 8OHdG in women but not in men
  • In the author's assessment, the occupational studies taken alone did not provide convincing evidence that smoking was a confounder
• The authors' conclusion: The author concluded that it is premature to use 8OHdG as a biomarker for decision making or regulatory purposes, though with further characterization it may serve as a biomonitoring tool in the future
• Limitations the authors state:
  • In most reviewed studies, exposure data were lacking, so elevated 8OHdG could only be linked to a general job category
  • It remains uncertain whether a fibrotic disease such as asbestosis can lead to elevated 8OHdG in peripheral blood cells
  • Every reviewed study measured only one 8OHdG endpoint
  • Only one reviewed study considered diet or dietary supplements

Topics

Medical terms in this study, explained in our Lexicon: Biomarker, Dose-response relationship, Confounding, Occupational Exposure, Oxidative Stress.

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