Organophosphate pesticide exposure and attention in young Mexican-American children: the CHAMACOS study.
BACKGROUND
Exposure to organophosphate (OP) pesticides, well-known neurotoxicants, has been associated with neurobehavioral deficits in children.


OBJECTIVE
We investigated whether OP exposure, as measured by urinary dialkyl phosphate (DAP) metabolites in pregnant women and their children, was associated with attention-related outcomes among Mexican-American children living in an agricultural region of California.


METHODS
Children were assessed at ages 3.5 years (n = 331) and 5 years (n = 323). Mothers completed the Child Behavior Checklist (CBCL). We administered the NEPSY-II visual attention subtest to children at 3.5 years and Conners' Kiddie Continuous Performance Test (K-CPT) at 5 years. The K-CPT yielded a standardized attention deficit/hyperactivity disorder (ADHD) Confidence Index score. Psychometricians scored behavior of the 5-year-olds during testing using the Hillside Behavior Rating Scale.


RESULTS
Prenatal DAPs (nanomoles per liter) were nonsignificantly associated with maternal report of attention problems and ADHD at age 3.5 years but were significantly related at age 5 years [CBCL attention problems: β = 0.7 points; 95% confidence interval (CI), 0.2-1.2; ADHD: β = 1.3; 95% CI, 0.4-2.1]. Prenatal DAPs were associated with scores on the K-CPT ADHD Confidence Index > 70th percentile [odds ratio (OR) = 5.1; 95% CI, 1.7-15.7] and with a composite ADHD indicator of the various measures (OR = 3.5; 95% CI, 1.1-10.7). Some outcomes exhibited evidence of effect modification by sex, with associations found only among boys. There was also limited evidence of associations between child DAPs and attention.


CONCLUSIONS
In utero DAPs and, to a lesser extent, postnatal DAPs were associated adversely with attention as assessed by maternal report, psychometrician observation, and direct assessment. These associations were somewhat stronger at 5 years than at 3.5 years and were stronger in boys.
Center for Children's Environmental Health Research, School of Public Health, University of California, Berkeley, Berkeley, California 94720, USA.
Amy R
AR
Marks
Kim
K
Harley
Asa
A
Bradman
Katherine
K
Kogut
Dana Boyd
DB
Barr
Caroline
C
Johnson
Norma
N
Calderon
Brenda
B
Eskenazi
D000293:Adolescent; D000328:Adult; D001288:Attention / Q000187:drug effects; D001289:Attention Deficit Disorder with Hyperactivity / Q000208:ethnology*; D002140:California / Q000208:ethnology; D002675:Child, Preschool; D015331:Cohort Studies; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D004785:Environmental Pollutants / Q000633:toxicity / Q000652:urine*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D017058:Mexican Americans / Q000208:ethnology; D015233:Models, Statistical; D009943:Organophosphorus Compounds / Q000633:toxicity / Q000652:urine*; D010575:Pesticides / Q000633:toxicity / Q000652:urine*; D011247:Pregnancy; D055815:Young Adult
D004785:Environmental Pollutants; D009943:Organophosphorus Compounds; D010575:Pesticides