There are concerns about genetic risks associated with long-term exposure to pesticides as these compounds may damage
DNA, resulting in mutations that eventually lead to
cancer, neurological, and reproductive adverse health effects. This study assessed DNA damage in intensive agricultural workers exposed to pesticides by determining the levels of N7-methyldeoxyguanosine (N7-MedG), an adduct known to be a robust
biomarker of recent exposure to chemical methylating agents. A cohort of 39
plastic greenhouse workers was assessed for changes in lymphocyte
DNA N7-MedG levels between low level and high level exposures during the course of a spraying season. The contributions of genetic polymorphisms of the
pesticide-metabolizing
enzymes paraoxonase-1 (PON1) and the
glutathione S-
transferases, GSTM1 and GSTT1, on N7-MedG levels and other potential confounders were also assessed. N7-MedG increased in the period of high
pesticide exposure as compared to the low exposure period (0.23 and 0.18 µmol N7-MedG/mol dG for the unadjusted and adjusted linear mixed models, P = 0.02 and 0.08, respectively). Significant decreased levels of erythrocyte
acetylcholinesterase and plasma
cholinesterase were observed in the high versus low exposure period in both the unadjusted (2.85 U/g
hemoglobin and 213.13 U/L, respectively) and adjusted linear mixed models (2.99 U/g
hemoglobin and 230.77 U/L, respectively), indicating
pesticide intake. In intensive agriculture workers, higher
pesticide exposure increased
DNA alkylation levels, further demonstrating the genotoxicity of pesticides in man. In addition,
pesticide-exposed individuals with inherited susceptible metabolic genotypes (particularly, null genotype for GSTM1 and the PON1 192R allele) appear to have an increased risk of genotoxic DNA damage. Environ. Mol.
Mutagen. 56:437-445, 2015. © 2014 Wiley Periodicals, Inc.