The comet assay as a tool for human biomonitoring of exposure to environmental and occupational agents – A summary of systematic reviews and meta-analyses

Résumé fourni par la source

This paper compiles results from six systematic reviews and meta-analyses on associations between environmental and occupational exposure to chemicals and levels of DNA strand breaks in human leukocytes, measured by the comet assay. There are no differences in effect sizes when using different comet descriptors. However, lower central tendencies are obtained by using a non-parametric test as compared to the standard parametric analysis, indicating that the standard meta-analyses tend to overestimate the effect size. The compiled results indicate that exposures can be sorted into three groups with decreasing effect size: high (pesticides), moderate (volatile organic compounds, heavy metals and antineoplastic drugs), and low (anaesthetic gases and air pollution). Interestingly, studies from middle-income countries have higher effect sizes than those seen in studies from high-income countries. This may be related to higher exposures or lower socioeconomic status in middle-income countries. However, there is also some co-variability between studies from middle-income countries and the risk of comet assay measurement bias, assessed as information provided in published papers. Lack of information on assay controls and blinded/coded sample analysis appears to be a general issue in studies on comet assay results. Risk of exposure misclassification is mainly related to the type of exposure; there are good biomarkers for some exposures (e.g. heavy metals), whereas other exposures are more challenging to assess with biomarkers (e.g. pesticides). In conclusion, all examined exposures result in significant increases in DNA strand breaks at the population level, though to varying degrees.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.