Fetal exposure to propoxur and abnormal child neurodevelopment at 2 years of age

Abstract

Objective Our aim was to determine the effects of fetal exposure to propoxur and pyrethroids, on child neurodevelopment at 2 years of age. Patients and Methods Mothers were prospectively recruited during mid-pregnancy in Bulacan, Philippines where multiple pesticides including propoxur, cyfluthrin, chlorpyrifos, cypermethrin, pretilachlor, bioallethrin, malathion, diazinon and transfluthrin are used. To detect prenatal exposure to these pesticides, maternal hair and blood, infant’s hair, cord blood, and meconium were analyzed for the pesticides by gas chromatography/mass spectrometry. Infants were examined at 2 years of age with 95.1% follow up rate and their neurodevelopment outcome was assessed by the Griffiths Mental Developmental Scale (N=754). Results Meconium analysis was the most sensitive method to detect fetal exposure to pesticides and exposure was highest for propoxur (21.3%) and the grouped pyrethroids (2.5% - bioallethrin, transfluthrin, cyfluthrin and cypermethrin). Path analysis modeling was performed to determine the effects of fetal exposure to propoxur and pyrethroids on the child’s neurodevelopment at 24 months of age while controlling for confounders. Only singletons and those with complete data for the path analysis were included (N=696). Using a path analysis model, there was a significant negative (β= −0.14, p<0.001) relationship between prenatal pesticide exposure to propoxur and motor development at 2 years of age after controlling for confounders, e.g., infant gender, socioeconomic status, maternal intelligence, home stimulation (HOME), postnatal exposure to propoxur and blood lead level at 2 years of age. Conclusion At 2 years of age, prenatal exposure to propoxur was associated with poorer motor development in children.

Developmental neurotoxicity of succeeding generations of insecticides

“…While these and other studies found a significant exposure to CAs during development, we found few epidemiological studies describing developmental effects of this class of insecticide, and all of them focused on prenatal exposures (SM Table 6). In the Philippines, Ostrea and collaborators (Ostrea Jr and others 2012) identified a significant relationship between prenatal propoxur exposure and slower motor development for children at 2 years of age. Shelton and collaborators (Shelton and others 2014) used commercial pesticide application data from the California Pesticide Use Report to investigate whether residential proximity to agricultural pesticides during pregnancy was associated with autism spectrum disorders or developmental delay (delayed cognitive or adaptative development).…”

Neurobehavioural effects of developmental toxicity

“…56 Propoxur, 57 a carbamate pesticide, and permethrine, 58 a member of the pyrethroid class of pesticides, have recently been linked to neuro developmental deficits in children.…”

Effects Of Simultaneous Prenatal Exposures To Organophosphate And Synthetic Pyrethroid Insecticides On Infant Neurodevelopment At Three Months Of Age

“…However, they did find an inverse relationship between mental scores and PBO exposure (1.2 point decrement per log-unit increase in PBO exposure). Ostrea Jr. et al reported no significant effect between exposures to the PYREs bioallethrin, transfluthrin, cyfluthrin and/or cypermethrin and child development at two years of age [16]. However, Xue et al found a negative and significant relationship of prenatal pyrethroid exposure and neural and mental development of Chinese infants at one year of age [17].…”