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Effects of Pesticide Exposure on Learning and Development
Patricia Moulton, Ph.D., Thomas Petros, Ph.D., Sally Pyle, Ph.D., Ric Ferraro, Ph.D., Patrick Kerr, M.A., Sue Offutt, Ph.D. & Dana Barr, Ph.D.
Regional Children’s Environmental Health Summit
Vail, Colorado
September 19, 2006
Funding for this study provided by the National Institute of Environmental and Health Sciences.
Pesticide Research Team
UND Faculty CDC Pesticide Laboratory PhlebotomistsThomas Petros Dana Barr Sandie AntonsonPatricia Moulton Charles Dodson Kristi GroveRic Ferraro Ralph Whitehead Tara JohnsoSally Pyle Dawn KoryntaSue Offutt Naomi SterfSteve Hawthorne Tara WaldalRuth Paur
Graduate Students Undergraduate StudentsHolly Dannewitz Cassandra LeeMatt Garlinghouse Silje LynneShyla Muse Ashley OlsonMatthew Myrvik Bethany ReuterAnna Marie Carlson Christine WegnerJason Douglas Catherine WoellPatrick KerrKaryn PlummKristi SatherCaitlin SchultzJen Short
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What are Pesticides?
• Herbicides• Insecticides• Rodenticides• Fungicides
Pesticide Exposure and Children
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Pesticide Exposure and Cognitive Ability in Children
Objectives of Current Study
Objective 1Examine the impact of chronic routine exposure to pesticides on
cognitive and motor performance in children between 7 and 12 years of
age, including memory performance, executive function performance,
motor performance, and performance on school-related achievement
tests.
Objective 2Measure the concentration of several pesticides and cholinesterase
in the blood or urine in children between 7 and 12 years of age and
examine associations between pesticide and cholinesterase
concentration and cognitive and motor performance.
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Red River Valley
Pesticides in North Dakota
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Participants
Pesticide Group= 64 children and their parents living on or next to an active farm or field
Control Group= 68 Children and their parents living at least one mile from an active farm or field
Physiological
Height and WeightBlood and Urine- pesticides, cholinesterase, trace minerals
Motor Cognitive
Grooved Pegboard Test Wechsler Intelligence Scale for Children-IVBenton Visual Retention Test California Verbal Learning Test ChildrenFinger Tapping Test Verbal Fluency TestHand-eye Coordination Test Continuous Performance Test
Wisconsin Card Sorting TestWechsler Individual Achievement Test- 2nd
ed- Reading & Listening Comprehension
Measurements- Children
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Measurements- Parents
Cognitive Behavioral
Wechsler Adult Intelligence Scale-III Child Behavior ChecklistVocabulary & Block Design ADHD Rating Scale-IV
Nutritional Status Developmental
NIH Diet History Questionnaire Tanner Pubertal Development TestFood Security module Developmental Milestones24-Hour Dietary Recall
Environmental
Pesticide use and exposure questionnaireSurveys on family and child medical history, sleep, occupation, income, education level
Measurements- Teachers
Behavioral
Teacher Report Form for Child Behavior ChecklistTeacher Report Form for ADHD Rating Scale-IV
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Intelligence Test Results
Child Demographics
9.68 9.24
3.39 3.56
02468
1012
Aver
age
Age Grade
Pesticide Control
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Child Full-Scale IQ*
99.3397.08
104.03 103.24
90
95
100
105
110
Male Female Male Female
Pesticide Control
Verbal Comprehension Index**
99.49
95.36
107.17
103.18
90
95
100
105
110
Male Female Male Female
Pesticide Control
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Verbal Comprehension Subtests
11.21(3.77)
10.83(2.68)
9.72(2.69)
9.87(2.53)
Comprehension*
10.15(3.43)
11.23(2.92)
9.16(2.69)
10.13(2.77)
Vocabulary*
10.52(4.12)
11.80(3.21)
9.36(3.03)
9.82(2.60)
Similarities**
FemaleMaleFemaleMale
ControlPesticide
Perceptual Reasoning Index/*
106.41
99.84
106.83104.42
90
95
100
105
110
Male Female Male Female
Pesticide Control
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Perceptual Reasoning Subtests
10.94(2.68)
10.89(2.54)
10.36(3.03)
10.56(2.49)
Matrix Reasoning
10.85(2.49)
10.91(2.63)
10.48(3.14)
11.36(2.61)
Picture Concepts
10.45(2.75)
11.43(2.77)
9.88(2.93)
11.15(2.37)
Block Design*
FemaleMaleFemaleMale
ControlPesticide
Working Memory Index
98.08 96.76
100.00 100.15
90
95
100
105
110
Male Female Male Female
Pesticide Control
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Working Memory Subtests
10.55(2.29)
10.66(3.04)
10.00(2.81)
9.79(2.69)
Letter- Number Sequencing
9.85(2.67)
9.57(2.83)
9.48(2.60)
9.77(2.47)
Digit Span
FemaleMaleFemaleMale
ControlPesticide
Processing Speed Index**
91.46
98.40
94.26
101.00
90
95
100
105
110
Male Female Male Female
Pesticide Control
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Processing Speed Subtests
11.00(2.02)
10.06(2.48)
10.44(3.01)
9.10(2.85)
Symbol Search*
9.45(2.89)
8.03(2.61)
9.52(2.42)
7.85(2.10)
Coding**
FemaleMaleFemaleMale
ControlPesticide
Parents Estimated Full Scale IQ
108.39 109.01
47.34 52.3232.63 30.81
0255075
100125
Estimated FSIQ DuncanSES HollingsheadSES
Pesticide Control
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Biological Measurements
Cholinesterase Concentrations (Ache)
4.39 4.35 4.37 4.11
012345
U/m
l
Male Female Male Female
Pesticide Control
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Cholinesterase Concentrations (Pche)
2.51 2.73 2.93 2.82
012345
U/m
l
Male Female Male Female
Pesticide Control
Acute Pesticide Analysis (Herbicides)
0.070.07
0.730.85
0.160.52
0.370.33
0.210.23
0 0.2 0.4 0.6 0.8 1
ng/ml
2,4,5-T
2,4-D
Metolachlor**
Acetochlor
Atrazine
Pesticide Control
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Acute Pesticide Analysis (Other)
0.41
1.41
0.23
0.36
0 0.5 1 1.5 2
ng/ml
Pyrethroids*
Deet**
Pesticide Control
Acute Pesticide Analysis (Organophosphates)
2.21.77
0.740.54 1.25
1.380.490.5
0.150.150.17
0.21.031.03
0 0.5 1 1.5 2 2.5
Isazaphos
Coumaphos
Pirmiphos methyl
Diazinon
Malathion
Parathion
Chloropyrifos
Pesticide Control
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7.846.92
2.842.94
0.150.111.21.13
20.2521.15
10.156.29
0 5 10 15 20 25
Dieldrin*
Hexaclorobenzene
Hepatpchlor
Mirex
Oxychlordane
Chlordane
Pesticide Control
Persistent Pesticide (Organochlorines)
0.81
2.21
1.38
2.96
0 0.5 1 1.5 2 2.5 3 3.5
Beta-hexachlorocyclohexane*
Gamma-hexachlorocyclohexane
ng/g
Pesticide Control
Persistent Pesticides (Lindane)
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1.3
4.16
101.62
118.3
3.56
4.36
0 20 40 60 80 100 120
ng/g
OP DDT
DDE
PP DDT
Pesticide Control
Persistent Pesticides (DDT)
Conclusions
• A significantly lower IQ was found in children living in areas of a great amount of pesticide use. Although, both groups were within the average range on IQ.
• This difference was independent of parents IQ and their socio-economic status.
• There is evidence of exposure to pesticides based on biological measurements. However, both groups were found to have been exposed to a number of pesticides.
• Next step is to run a multiple regression to examine the association between the biological measurements of pesticides and the IQ results along with the other cognitive tasks.
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Significant Cholinesterase Correlations
SymPche
PSICompAche
PositiveCorrelations
NegativeCorrelations
Significant Herbicide/Other Correlations
SimDeet
Pyrethroids
2,4,5-T
Symb2,4-D
VCI, Sim, VocMetolachlor
Acetochlor
BDAtrazine
PositiveCorrelations
NegativeCorrelations
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Significant Organophosphate Correlations
Chloropyrifos
Parathion
VocMalathion
Diazinon
PRI, BDPirmiphos methyl
Coumaphos
Isazaphos
PositiveCorrelations
NegativeCorrelations
Significant Organochlorine Correlations
BDChlordane
Oxychlordane
WMIMirex
MRHepatochlor
BDHexaclorobenzene
Dieldrin
PositiveCorrelations
NegativeCorrelations
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Significant Lindane & DDT Correlations
OP DDT
DDE
PRI, PC, MRPP DDT
Beta-hexachlorocyclohexane
VocGamma-hexachlorocyclohexane
PositiveCorrelations
NegativeCorrelations
Limitations and Future Directions
• The measurement of pesticide exposure is complex due to the large number of potential pesticides to measure and the number of variations in exposure.
• Future studies are needed to further explore the association between particular groups of pesticides and IQ and to examine the longitudinal effects of pesticide exposure.
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For more information contact:
Patricia Moulton, Ph.D.
Thomas Petros, Ph.D.