PON1 Q192R Gene Polymorphism and Pesticide Exposure Status of Rice Farmers, Suphan Buri, Thailand

Abstract

PON1 Q192R (rs662) polymorphism in coding region is conveying differential catalytic activity of
organophosphate. Study was aimed to investigate PON1 Q192R gene polymorphisms in rice farmers along
with pesticide knowledge and practices; and to evaluate the relationship of gene polymorphisms and serum
cholinesterase (SChE) levels. Information of pesticide exposure, knowledge and practices were collected
from 50 rice farmers and 50 control respondents by questionnaire interviewing. Each blood sample was
obtained by venipuncture and prepared to serum for SChE activity test by paper test and automatic analyzer;
to EDTA blood for genotyping by PCR-RFLP. Exposure status, knowledge and practices on pesticide use
were represented as frequency. Chi-square was used to analyze on the different of personal information;
and of polymorphism. Independent t-test was used for comparison of SChE levels. Person correlation was
evaluated relationship between SChE level and genotypes. 60% of rice farmers were used pesticide over
10 years. Rice farmers were long-term pesticide exposure with good on pesticide knowledge, however
poorly practice. Means of SChE level of both groups were within reference value and significantly different
(p = 0.033). Polymorphisms were included wild type (QQ), heterozygote (QR) and homozygote (RR);
and were significantly different between rice farmers (high frequency of RR genotype) and control (p =
0.02). Relationship of polymorphism and SChE level were negative correlated (r = -0.261; p = 0.031). This
polymorphism may useful biomarker for chronic pesticide exposure in Thai rice farmer and corresponded to
decline of serum cholinesterase; and RR genotype was high risk group.