title: Trends in long term exposure to propoxur and pyrethroids in young children in the Philippines.
abstract: OBJECTIVE
  Pesticides are neurotoxic and can adversely affect children's neurobehavioral outcome. Ongoing pesticide exposure has to be monitored in the study of long term outcome of pesticide adverse effects since changes in the type and amount of exposure can influence outcome. The aim of this paper is to describe the trend in long term pesticide exposure in children through the analysis of pesticides in their hair.
  
  
  METHODS
  As part of an NIH study on the long term effects of pesticide exposure in young children, ongoing exposure to pesticides was determined by the analysis of children's hair for propoxur and pyrethroids by gas chromatography/mass spectrometry at 2, 4 and 6 years of age.
  
  
  RESULTS
  There were significant changes in the prevalence and concentration of propoxur and pyrethroids in children's hair at 2, 4 and 6 years of age. At ages 2 and 4 years, the prevalence of propoxur exposure increased from 12.4% to 24.1% (p<0.001) but dramatically decreased to 1.7% at 6 years (p<0.001). For bioallethrin, the prevalence of exposure steadily increased from 2 years (0.7%, p<0.001) to 4 years (12.4%, p<0.001) and to 6 years (18.4% p<0.001). Exposure to transfluthrin significantly increased from 4 years (1.0%) to 6 years (9.2%, p<0.001). There were also significantly higher median concentrations of bioallethrin at 2 compared to 4 years and for propoxur at 2 years compared to 6 years. Between 4 and 6 years, there was a higher median concentration of propoxur at 4 compared to 6 years and for transfluthrin and bioallethrin, at 6 compared to 4 years.
  
  
  CONCLUSIONS
  Changes in the prevalence and concentration of exposure to propoxur and pyrethroids in children at 2, 4 and 6 years of age are related to the progress in ambulation of young children and to changes in the formulation of home spray pesticides. Thus, periodic monitoring of pesticide exposure is necessary when studying the long term effects of pesticide exposure in the neurodevelopment of young children.
authors.affiliation: Department of Pediatrics, Hutzel Women's Hospital, The Carman and Ann Adams Department of Pediatrics, Children's Hospital of Michigan, Wayne State University, Detroit, MI 48201, USA. Electronic address: enrique.ostrea@gmail.com.
authors.forename: Enrique M
authors.initials: EM
authors.lastname: Ostrea
authors.affiliation: Institute of Child Health and Human Development, University of the Philippines Manila, National Institutes of Health, Philippines.
authors.forename: Esterlita
authors.initials: E
authors.lastname: Villanueva-Uy
authors.affiliation: Department of Pediatrics, Hutzel Women's Hospital, The Carman and Ann Adams Department of Pediatrics, Children's Hospital of Michigan, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Dawn
authors.initials: D
authors.lastname: Bielawski
authors.affiliation: Department of Pediatrics, Hutzel Women's Hospital, The Carman and Ann Adams Department of Pediatrics, Children's Hospital of Michigan, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Sarah
authors.initials: S
authors.lastname: Birn
authors.affiliation: Department of Family Medicine and Public Health Sciences, Wayne State University, Detroit, MI 48201, USA.
authors.forename: James J
authors.initials: JJ
authors.lastname: Janisse
mesh_terms: D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D004781:Environmental Exposure / Q000032:analysis*; D006197:Hair / Q000737:chemistry; D006801:Humans; D010575:Pesticides / Q000032:analysis*; D010679:Philippines; D001074:Propoxur / Q000032:analysis*; D011722:Pyrethrins / Q000032:analysis*
chemical_list: D010575:Pesticides; D011722:Pyrethrins; D001074:Propoxur
keywords: Biomarkers; Environmental exposure; Hair; House dust; Pesticides; Young children