Urinary 3,5,6-trichloro-2-pyridinol (TCPY) in pregnant women from Mexico City: Distribution, temporal variability, and relationship with child attention and hyperactivity

• Authors: Gamola Z. Fortenberry, University of Michigan; John D. Meeker, University of Michigan; Brisa N. Sanchez, University of Michigan; Dana Boyd Barr, Emory University; Parinya Panuwet, Emory University; David Bellinger, Harvard University; Lourdes Schnaas, National Institute of Perinatology; Maritsa Solano-Gonzalez, National Institute of Public Health; Adrienne S. Ettinger, University of Michigan; Mauricio Hernandez-Avila, Ministry of Health Mexico; Howard Hu, University of Toronto; Martha Maria Tellez-Rojo, National Institute of Public Health
• Journal Title: International Journal of Hygiene and Environmental Health
• Volume: Volume 217, Number 2-3
• Publisher: Elsevier | 2014-03-01, Pages 405-412
• Type of Work: Article | Post-print: After Peer Review
• Publisher DOI: http://doi.org/10.1016/j.ijheh.2013.07.018
• Subjects: Health Sciences, Public Health; Psychology, Developmental
• Keywords: Science & Technology; Life Sciences & Biomedicine; Public, Environmental & Occupational Health; Infectious Diseases; Biomarker; Organophosphates; Pesticides; Exposure; ADHD; Children; PRENATAL CHLORPYRIFOS EXPOSURE; BLOOD LEAD LEVELS; ORGANOPHOSPHATE PESTICIDE EXPOSURE; PLACEBO-CONTROLLED TRIAL; DEVELOPMENTAL NEUROTOXICITY; NEUROBEHAVIORAL DEVELOPMENT; BEHAVIORAL ALTERATIONS; AMERICAN CHILDREN; DISORDER; NEURODEVELOPMENT

Abstract

Attention Deficit Hyperactivity Disorder (ADHD) is the most commonly diagnosed and studied cognitive and behavioral disorder in school-age children. The etiology of ADHD and ADHD-related behavior is unclear, but genetic and environmental factors, such as pesticides, have been hypothesized. The objective of this study was to investigate the relationship between in utero exposure to chlorpyrifos, chlorpyrifos-methyl, and/or 3,5,6-trichloro-2-pyridinol (TCPY) and ADHD in school-age Mexican children using TCPY as a biomarker of exposure. The temporal reliability of repeated maternal urinary TCPY concentrations across trimesters was also explored (N= 21). To explore associations with ADHD-related outcomes in children, third trimester urinary TCPY concentrations in were measured in 187 mother-child pairs from a prospective birth cohort. Child neurodevelopment in children 6-11 years of age was assessed using Conners' Parental Rating Scales-Revised (CRS-R), Conners' Continuous Performance Test (CPT), and Behavior Assessment System for Children-2 (BASC-2). Multivariable linear regression models were used to test relationships for all children combined and also stratified by sex. Intraclass correlation coefficients (ICC) calculations were based on a random effects model. The ICC was 0.41 for uncorrected TCPY, and ranged from 0.29 to 0.32 for specific gravity-corrected TCPY. We did not observe any statistically significant associations between tertiles of maternal TCPY concentrations and ADHD-related outcomes in children. However, compared to the lowest tertile we found suggestive evidence for increased ADHD index in the highest TCPY tertile in boys (β= 5.55 points; 95% CI (-0.19, 11.3); p= 0.06) and increased attention problems for the middle tertile in girls (β= 5.81 points; 95% CI (-0.75, 12.4); p= 0.08). Considering the continued widespread agricultural and possible residential use of chlorpyrifos and chlorpyrifos-methyl in Mexico and the educational implications of cognitive and behavior deficits, these relationships deserve further study.