Changes of blood cholinesterase activities among pesticides-exposed agricultural workers in Iraq: A meta-analysis.

Numerous studies in Iraq have attempted to determine blood cholinesterase (ChE) activities with varying results in agricultural workers and veterinarians exposed to pesticides. This meta-analysis answers the specific inquiry of whether or not blood ChE activities decrease in agricultural workers exposed previously to pesticides. The meta-analysis included 14 records of blood ChE activities extracted from 12 studies after employing the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). These records comprised ChE activities in agricultural workers exposed to pesticides (n = 635) versus their respective control cohorts (n = 416). We employed the one-group random effects model for the meta-analysis and the Newcastle-Ottawa Scale (NOS) to examine study quality. The combined effect size of pesticides exposed group (% ChE activity versus control) was significant at 86.13 %. Heterogeneity (I = 49.86 %) was moderate. Subgroup analysis of the enzyme source (plasma/serum and erythrocytes/whole blood) revealed that plasma effect size was significant at 82.36 % compared to erythrocytes (92.08 %), which was not significant. No publication bias existed. The studies were of high quality (NOS ≥ 7). The present study is the first meta-analytic report of associating reduced blood ChE activities with pesticides exposure in Iraqi agricultural workers. Reduced pseudo ChE (plasma, serum) activity was the most significant indicator of pesticides exposure. Nevertheless, we recommend biomonitoring erythrocyte and even whole blood ChE activities in pesticides-exposed individuals, because of scarce information on the type and frequency of pesticides employed by Iraqi agricultural workers. Our findings call for a national integrated plan and improved regulations for safer and judicious pesticides applications and follow-up practices in Iraq in order to reduce potential health hazards and environmental risks.