The alkaline comet assay has been widely used to determine genotoxicity in human populations exposed to arsenic. The sample sizes of earlier studies were usually small, and inconsistent results were found. Meta-analyses can merge the results of multiple studies of the same type and increase the credibility of the conclusion by increasing the sample size. Thus, to investigate the monitoring effect of alkaline comet assay on genotoxicity for arsenic exposed population, meta-analyses were performed. Thirteen studies were found to meet the inclusion criteria and were included in this study; of them, twelve articles were of medium quality (15-20 points), only one study was of high quality (21-27 points). Meta-analyses showed that the overall estimates of Mean Ratio (MR, defined as the mean value of the response in the exposed group divided by that in the reference group) were 2.81(95 % confidence interval (CI) 1.93-4.10); 2.37(95 % CI, 1.73-3.26), and 1.69(95 %CI, 1.29-2.20) for comet tail length, % tail DNA, and tail moment, respectively. This shows that the level of DNA damage in arsenic exposed population is significantly higher than that in control populations. A meta-analysis of the correlation coefficients showed that the overall estimate was 0.52 (95 %CI, 0.48∼0.56, P<0.05) with all correlation coefficients included, but it changed to 0.24 (95 %CI, 0.17∼0.28, P<0.05) when two abnormal correlation coefficients were excluded, suggesting there was a positive correlation between arsenic load in vivo and DNA damage, but the overall estimate value of coefficients was unstable. Therefore, we conclude that the alkaline comet assay can be used as an effective genotoxic biomonitoring tool for arsenic-exposed populations. However, more and higher-quality studies are still needed to verify its actual application value.
Keywords: Arsenic; Comet assay; Genotoxicity; Human biomonitoring; Meta-analysis.
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