Adverse effect of pre- and postnatal exposure to carbamate and pyrethroid pesticides on cognition in children at 4 and 6 years of age: A prospective study

Objective@#To determine the adverse effect of pre- and postnatal exposure to carbamate (propoxur) and pyrethroid pesticides on children's cognitive functions at 4 and 6 years of age. @*Method@#As part of a prospective cohort study among children with known pre- and postnatal exposure to propoxur and pyrethroids, children were examined at time points, 4 and 6 years, to determine the adverse effect of pesticide exposure on neurocognitive function, i.e., intelligence (IQ) using the WPPSI-III test. Pre- and postnatal pesticide exposures were measured by meconium and hair analysis, respectively, using gas chromatography-mass spectrometry (GCMS).@*Results@#Seven hundred twenty-four (724) maternal/children dyads were seen at four years and 717 at six years of age. Their mean (SD) full-scale IQ was low on average: 83.9 (10.2) at four years and 83.6 (8.6) at six years. Prenatal but not postnatal exposure to propoxur (-0.139, p=0.01) and pyrethroids (-0.097, p=0.05) were significantly correlated (negative) with full-scale IQ at four years but not at six years. The confounders that were significantly correlated to full-scale IQ at four and/or six years of age were maternal IQ, child’s weight, height, head circumference, socio-economic status, child environment, and stimulation at home (HOME) violence or abuse at home. Regression analysis of pesticides and confounders showed similar results, except for weight and head circumference.@*Conclusion@#We conclude that prenatal exposure to propoxur and pyrethroids had a negative effect on the children’s IQ at four years but no longer at six years. Thus, the ability of the child’s IQ to recover from the adverse effect of intrauterine pesticide insult may be attributable to the neuronal plasticity of its brain. Similarly, confounders to these outcome measures are multiple and are essential to address when evaluating the effect of pesticides on neuro-cognitive development in children.

The prevalence of developmental delay among Filipino children at Ages 6, 12 and 24 months based on the Griffiths mental development scales

@#<p><strong>BACKGROUND:</strong> To determine prevalence of delay in 5 developmental domains among Filipino children at 6, 12 and 24 months and investigate influence of socioeconomic status, maternal intelligence, gender and home stimulation. Variations and developmental domains as reliable indicators of potential delay were determined.</p><p><strong>METHODS:</strong> 754 maternal/ infant dyads were followed up until 2 years old. The Griffiths Mental Development Scales determined sub-quotient scores in locomotor, personal/social, hearing/language, eye-hand coordination and performance subscales before averaging for General Quotient(GQ) score. Score < 85 was considered delayed.</p><p><strong>RESULTS:</strong> Low GQ scores were noted in 5.4% at 6 months, 19.1% at 12 months and 11.0% at 24 months old. GQ scores were lowered by performance subscale at 6 months, hearing/language and performance at 12 months and hearing/language at 24 months. No single subscale consistently lowered GQ across time. Only 4.2% maintained low GQ scores in all three ages.</p><p><strong>CONCLUSION:</strong> Prevalence of developmental delay varied across 24 months with highest rates noted at 12 months of age. No developmental domain consistently lowered test scores and no test age was predictive of future outcome but focused early intervention according to age is suggested. Home environment, higher socioeconomic status, maternal IQ and supervision were associated with improved potential.</p>