Paraoxonase (PON1) polymorphisms as a biomarker of susceptibility to organophosphate toxicity among a cohort of Singaporean workers

Abstract

Organophosphate (OP)-containing pesticides are extensively used worldwide. OP exposure studies have revealed numerous health effects attributed mainly to acetylcholinesterase inhibition. The enzyme human serum paraoxonase (PON1) is involved in detoxification of OP compounds. PON1 polymorphisms have been shown to affect susceptibility to OP exposure. Here, we investigated the effect of OP exposure on pest control workers and assessed the distribution of two common PON1 polymorphisms locally.Our study showed that cholinesterase levels among the exposed were not lower than those in the unexposed group. PON1 activity and consequently PON1 polymorphisms differed among ethnic groups, implying ethnicity could be an important surrogate for identifying susceptible groups in case of OP exposure. Although OP poisoning is rare among occupationally exposed workers in Singapore, this information would be useful for other developing countries that have large populations of Chinese, Malays and Indians where OP exposure could be very high especially in agricultural settings.