Objective To investigate whether alcohol drinking and polycyclic aromatic hydrocarbons (PAHs) exposure have interaction effects on the peripheral blood 8-oxoguanine DNA glycosylase (OGG1) methylation in coke oven workers.
Methods A total of 303 workers from a coking plant were recruited. General information was collected by questionnaire survey. Blood samples and urinary samples were collected to test the urinary concentrations of four PAHs metabolites, including 2-hydroxynaphthalene (2-NAP), 2-hydroxfluorene (2-FLU), 9-hydroxyphenanthren (9-PHE), and 1-hydroxypyrene (1-OHP) by high performance liquid chromatography with fluorescence detection. The methylations on four sites in OGG1 (106 bp, 121 bp, 126 bp, and 142 bp from the 5' end of the first exon) were detected by pyrosequencing. Multiple logistic regression analysis was conducted to assess the relationship of OGG1 methylation with PAHs and alcohol drinking; trend analysis and restrictive cubic spline were adopted to analyze the dose-response relationship.
Results The participants were divided into four groups by quartiles (Q1-Q4) of urinary 1-OHP concentration. There was a significant difference in age distribution between different 1-OHP level groups (P=0.033). The levels of 2-FLU and 9-PHE showed increasing trends with higher 1-OHP levels. The results of multivariate logistic regression analysis revealed that urinary 1-OHP (OR=2.97, 95% CI:1.20-7.38) and alcohol drinking (OR=1.67, 95% CI:1.01-2.79) were closely associated with the hypermethylation on site 4 in OGG1 after adjusting for sex, age, education, smoking, heating mode, 2-NAP, 2-FLU, and 9-PHE. However, there were no significant relationships between the other three metabolites and OGG1 methylation. The coke oven workers with both urinary 1-OHP Q4 level and reported alcohol drinking had a higher risk of hypermethylation on site 4 in OGG1 than the workers with urinary 1-OHP Q1 level and without alcohol consumption (OR=4.00, 95% CI:1.19-13.47).
Conclusion Interactive effect of urinary 1-OHP levels and drinking on hypermethylation on site 4 in OGG1 is identified among coke oven workers.
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