2. Agricultural Health Study http://www.aghealth.org
A large, prospective
cohort study
Goal: Establish a large group of people associated with pesticide application and follow them for many years to evaluate the relationship between agricultural exposures and disease

3. Agricultural Health Study Example of a Prospective Cohort Study
Time
Disease
Exposed to
Agricultural
Risk Factor
Defin
Popula
(Certif
Pestici
Applica ed
tion
ied de
tors)
No disease
Non-
Randomized
Unexposed to
Agricultural
Risk Factor
Disease
No disease
Direction of Inquiry

4. Topics Covered Study Design Pesticide Exposure Assessment
Major Exposures and Health Effects
Pesticides & Human Carcinogenicity

5. Design Pesticide Certification Program (North Carolina and Iowa)
Main Cohort Study
(Cohort Identification/Questionnaire Administration)
Main Cohort Study
Morbidity and Mortality
Follow-Up
Goal: 75,000 study subjects
(Enrolled 89,658)
Nested Case-Control
Studies
a. Cancer
b. Non-Cancer
Pesticide
Exposure
Assessment

6. Collaborating Institutions
Executive
Committee
National Cancer Institute
National Institute of Environmental Health Sciences
Environmental Protection Agency
National Institute for Occupational Safety and Health
Field Stations
University of Iowa
Battelle/Centers for Public Health Research & Evaluation
Coordinating Center (Westat, Inc.)
Operations
Committee

7. Key Organizations Affiliated with Iowa Field Station
Center for Health Effects of Environmental Contamination
College of Public Health
Department of Epidemiology (AHS Iowa Field Station)
Department of Occupational and Environmental Health
State Health Registry of Iowa
Iowa Department of Agriculture and Land Stewardship
Iowa State University Extension Service

8. Study Overview Phase I 1993-97 Phase II 1998-03 Phase III 2004-10
Pesticide Applicators Recruited at Training (84%)
Spouses of Applicators (75%)
CATI follow-up interview (~70%)
Buccal Cell Collection (~40%)
Diet Questionnaire (~40%)
CATI follow-up interview (~50%)
Buccal Cell Collection (N=~1000 cancer subjects)
Cancer and Mortality Follow-up
Phase II
Phase III

9. Enrollment in the Agricultural Health Study by County
(an additional 392 enrollees have an out-of-state address)
762
474
401
393
316
421
573
625
628
575
1,098
1,431
908
598
501
759
734
477
652
869
881
662
1,212
671
902
562
613
452
796
879
930
781
1,037
1,044
652
830
433
599
546
627
482
911
627
733
640
920
616
574
661
931
416
393
695
631
810
748
727
756
401
302
532
362
801
501
618
523
635
631
1,113
704
531
234
368
422
495
688
849
403
484
443
341
262
124
162
114
185
250
679
325
603
514
194
319
174
218
171
196
268
458

10. Sources for Information
Questionnaires (
Environmental monitoring, literature, PHED
Disease registries
Biomarkers

11. Cohort Characteristics at Enrollment
PA (Farmers) CA Spouse of PA
Average age: yrs yrs yrs
Race:
White % % %
Nonwhite % % %
Gender:
Men % % %
Women % % %
Education:
12+ years % % %
Current smoker: % % %
Personally applied
pesticides:
11+ yrs % % %
10+ days/yr % % %
60+ days/yr % % %
(From: Alavanja MCR et al. Scand J Work Environ Health 31 Suppl 1:39-45, 2005)

12. Major Exposures and Health Effects under Study
PESTICIDES
Animals
Engine exhaust
Solvents
Organic and inorganic dust
Health Effects
Cancer
Respiratory Health
Reproductive Health
Neurologic Disease
Work Place Injuries

13. Exposure Assessment Procedures Source: Dosemeci M et al
Exposure Assessment Procedures Source: Dosemeci M et al. Annals of Occupational Hygiene 46(2): , 2002
Questionnaire Data
Identification of
Exposure Scenarios
Intensity Info.
Mixing status
Application type
Repair equipment
PPE use
Work habit
Personal hygiene
Data from
Literature
Assigning Exposure
Scores for Each
Scenario
AHS Surveys
PHED
Time Info.
-Duration of use
- Frequency of use
- Calendar time
Merging
Subject &
Chemical-specific
Assessment

14. Exposure Metrics In the AHS
Lifetime Exposure-Days (specific pesticide) = Yrs Application (specific pesticide) * Days of application/Yr (specific pesticide)
Intensity-Weighted Lifetime Exposure-Days (specific pesticide) = Life time Exposure Days (to specific pesticide) * Intensity of exposure
Lifetime Exposure-Days (all pesticides) = Yrs Application * Days of application/Yr
High Pesticide Exposure Events = acute events involving unusually high exposures because of spills, immersions, etc.

15. Number of Pesticides Per Applicator, AHS 1999 - 2003
Number of Applicators
Number of Pesticides Reported Used

16. Source of Vital Status for Cohort through December 31, 2007 (reported February 17, 2010)

17. Cancer Incidence Linkage through Malignant Cancer Incidence after Enrollment by Type of Applicator and State

18. Commercial Applicators
Update of Cancer Standardized Incidence Ratios (SIR) through 2006, North Carolina and Iowa Combined (Koutros S et al. An update of cancer incidence in the Agricultural Health Study. Journal of Occupational and Environmental Medicine (in press) )
Cancer
Private Applicators
Commercial Applicators
Spouses
SIR
(N)
95% CI
All sites
0.85 (4316)
0.93
(219)
0.82
(1896)
Lung
0.48
(436)
0.75
(26)
0.42
(133)
Colon
0.87
(339)
0.98
(17)
0.83
(144)
Prostate
1.19
(1719)
1.28
(73)
1.05
(7)
Female breast
0.95
(33)
1.00
(770)
Multiple myeloma
1.20
(71) 1
0.94
(21)

19. Number of Deaths by Cause through 2007
Cause of Death Appl Spouse Total
Cancer 1, ,289
Heart Disease 1, ,668
Injuries
Other circulatory
Respiratory
Other
All 4, ,539 6,419
% of total

20. Update of Cancer Standardized Mortality Ratios (SMR) through 2007, North Carolina and Iowa Combined (Waggoner JK et al. Mortality in the Agricultural Health Study: American Journal of Epidemiology (in press))
Cause of Death
Applicators
Spouses
SMR (N)
95% CI
Transportation Motor vehicle - nontraffic
2.80 (25)
(0)
Other injury -machine
4.15 (62)
(3)
Intentional self-harm
0.57 (106)
0.32 (9)
All cancers
0.61 (1624)
0.65 (665)
Heart diseases
0.54 (1376)
0.47 (292)
Respiratory
0.38 (346)
0.30 (92)

21. Publications (n=137) as of September 2010 at www.aghealth.org
Methods (n=11)
Exposure Assessment (n=32)
General (n=21)
High Pesticide Exposure Events (n=6)
Environmental Measures (n=5)
Health Outcomes (n=87)
Mortality (n=5)
Cancer (n=41)
Neurological (n=9)
Respiratory (n=11)
Reproductive (n=9)
Other (n=12)
Diet (n=1)
Injury (n=6)
Iowa Field Station 69 IRB-approved new projects into 18th year of AHS

22. Cancer Causal Inference in AHS: What are we looking for?
Biological
Initial Replication Evidence in
Findings later in time Humans
Iowa
North
Carolina
License
Type
Dose-
Response
Dose-
Response
YES

23. Pesticides Evaluated for Human Carcinogenicity
18 commonly used pesticides associated with one or more of 8 cancer types
Bladder, colon, leukemia, lung, skin melanoma, multiple myeloma, prostate, rectum
9 other commonly used pesticides possibly associated with one or more of 5 cancer types
Colon, leukemia, multiple myeloma, NHL, rectum
Prostate and multiple myeloma are furthest along for biologic evidence in humans

24. Prostate Cancer Risk by Exposure Status with and without a First Degree Family History
(follow-up studies scheduled)
Pesticide
PC risk, no family history of PC
PC risk, family history of PC
Statistical interaction,
PC history & Pesticide Exposure
Odds Ratio
95% C.I.
Fonofos
0.92
1.80
2.04
Coumaphos
0.86
2.17
2.58
Alavanja MCR, et al. American Journal of Epidemiology. 2003: 157 (9):
Similar results found for permethrin, phorate, chlorpyrifos.

25. Biologic Evidence Prostate Cancer Nested Case-Control Study (Gene x Environment Interaction)
8q24
Hormonal Pathway
DNA repair
Xenobiotic metabolism
Lipid metabolism
Telomere length
DNA methylation
Others

26. Observation from AHS (follow-up evaluations scheduled)
Multiple Myeloma in excess in AHS SIR=1.34 ( ) - Alavanja MCR, et al. Scand J Work Environ Health 2005:31 suppl 1:39-45); SIR= 1.20 ( ) - most recent incidence data through 2006
Monoclonal gammopathy of undetermined significance (MGUS) – 2-fold significant excess in AHS (Landgren O. et al., Blood (2009), 113(25); ).
Several widely used pesticides are associated with elevated MGUS levels (Landgren O. et al., Blood (2009), 113(25); ).
Odds ratio for multiple myeloma = 5.7 ( ) for heaviest users of permethrin (Rusiecki J, et al., Environ. Health Perspectives (2009), 117; ).

27. Biologic Evidence AHS Biomarker Study Markers of Potential Interest
Telomere length
DNA methylation
MGUS
Monoclonal B-cell lymphocytosis (MBL)
Mitochondrial DNA copy number
Immune suppression among pesticides associated lymphomas and leukemias
Cytokines including interleukin IL10 and tumor necrosis factor (TNF)
Chromosome aberrations and pesticides associated with lymphomas and leukemias
Urinary metabolite pesticide concentrations

28. Epidemiology Research: Potential Contributions
Characteristics
No extrapolation of results from lab animal to human
No extrapolation from high exposures in animal testing to lower exposure in human experience
Prospective study to minimize information bias
Control for confounders to obtain valid risk estimates
Comprehensive exposure assessment to minimize misclassification
Generate biological results to assess biological plausibility and modes of action and identify susceptible sub-populations
Results generalizable for the chemical evaluated in adults (within the range of exposures of the study)

29. Translational Research
Contrary to widely held misperceptions, AHS research has demonstrated following attributes:
Pesticide applicators have accurate knowledge of pesticides they apply
Questionnaire-based exposure assessments significantly correlated with field measurements of pesticides in urine and on skin
Although each applicator uses a number of different pesticides, the use of these pesticides is generally not highly correlated and rarely cause confounding (an alternative explanation)
Because of these attributes, US EPA recently announce in Federal Register that epidemiological data from the AHS will be used in its risk assessment of pesticides
This marks significant departure from EPA practice, which has focused on short-term bioassays and animal testing in risk assessment

30. ?? ?? Questions ?? ??