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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.

pmoulton@medicine.nodak.edu

Thomas Petros, Ph.D.

thomas.petros@und.nodak.edu