Children's developing brains are susceptible to pesticides. Less is known about the effect of exposure to chlorpyrifos and pyrethroids on executive functions (EF). We measured urinary 3,5,6-trichloro-2-pyridinol (TCPy), a metabolite of chlorpyrifos, and urinary 3-phenoxybenzoic acid (3-PBA), a general, nonspecific metabolite of pyrethroids in first-grade children from Montevideo, Uruguay (n = 241, age 80.6 ± 6.4 months, 58.1% boys). EFs were assessed with the Intra-dimensional/Extra-dimensional shift (IED), Spatial Span (SSP), and Stockings of Cambridge (SOC) tests from the Cambridge Neuropsychological Test Automated (CANTAB) Battery. General intellectual ability (GIA) was assessed using the Woodcock-Muñoz Cognitive battery. Median (range) urinary TCPy and 3-PBA levels were 16.7 (1.9, 356.9) ng/mg of creatinine and 3.3 (0.3, 110.6) ng/mg of creatinine, respectively. In multivariable generalized linear models, urinary TCPy was inversely associated with postdimensional errors on the IED task β [95% CI]: -0.11 [-0.17, -0.06]. Urinary 3-PBA was inversely associated with the total number of trials -0.07 [-0.10, -0.04], and the total number of errors -0.12 [-0.18, -0.07] on the IED task. When TCPy and 3-PBA were modeled together, the associations did not differ from single-metabolite models. We found no evidence of effect modification by blood lead level (BLL). Pesticide exposure may affect EF performance in urban children.
Keywords: child health; chlorpyrifos; cognition; executive function; pesticide exposure; pyrethroids.