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Disposition of the
Air Force Health Study
Michael A. Stoto, PhD
Institute of MedicineApril 14, 2005
Disclaimers
• I chair the official advisory committee in my personal capacity– Not a RAND project
• Some information from AFHS
• Opinions are my own, based on following the study closely for a decade– Not Air Force, RHAC, RAND, or NAS/IOM
Outline• AFHS as a national resource to study
– Agent Orange and Vietnam herbicides
– Dioxin
– Veterans’ and occupational health issues
– Aging
– Chronic disease risks
– Other environmental health issues
• Disposition options and issues
• Congressional and Presidential mandate
• To conduct a 20-year prospective epidemiological study of herbicide exposure and health, mortality, and reproductive outcomes in veterans of Operation Ranch Hand
AFHS Purpose
Study Design
• Index group: Ranch Hand veterans (N=1,208)
• Control population: Air Force veterans of Southeast Asia (N=19,080)
• Examined controls matched on age, race, military occupation (N=1,668)
Study Design (Continued)• Multiple endpoints
– Mortality, morbidity, reproductive outcomes
• Repeated physical examinations, interviews and mortality assessments, plus– Biological samples– Medical records– Military and civilian employment history
• Herbicide and dioxin exposure based on military records, military occupation, serum dioxin measurement
Morbidity Endpoints
• General Health
• Cancer
• Neurological
• Psychological
• Gastrointestinal
• Dermatological
• Endocrinological
• Immunological
• Pulmonary
• Cardiovascular
• Renal
Study Schedule
1960 1970 1980 1990 2000 2010
Protocol DevelopmentPhysical Examination
Exposure period
Serum dioxin (ppt)
With chloracne
Without chloracne
New Zealand sprayers
German plant workers
quintile 5
quintile 4
quintile 3
quintile 2
NIOSH workers - quintile 1
Enlisted men - non-flying
Enlisted men - flying
Officers - flying (pilots)
Officers - flying (navigators)
Officers - non-flying
Controls
High
Medium
Low
Controls
Median serum dioxin levels in selected populations
157
4540
16,600
Ground troop veterans in AOVS
Ranch Hand veterans
Occupational exposures
Seveso, Italy population
355
0 20 40 60 80 100 1000 10,000
Numbers of Veterans Physically Examined
Year Ranch Hand Comparison Total
1982
1985
1987
1992
1997
2002
1,045
1,016
995
952
869
777
1,224
1,293
1,299
1,281
1,252
1,174
2,269
2,309
2,294
2,233
2,121
1,951
Study Materials
Item Number
Biological specimensX raysPhysical examinationsQuestionnairesDeath recordsViable conceptionsNonviable conceptions
74,57719,59413,17720,645
2,8196,8011,490
Knowledgeable Staff
Research Results
Study Disposition• Veterans Benefits Act of 2003 (PL108-
183): NAS study to address (among others)– Potential value of extending the study– Scientific merit of retaining and
maintaining medical records, specimens, other data
– Obstacles to retaining materials– Advisability and cost of making
specimens available to independent researchers
Extending the Study
• Due to age and number of remaining participants, value of extending the study to do more physical examinations is not clear
• Consider
– Value of completing research in progress
– Monitoring mortality
Retaining and Maintaining Materials• Not the original goal, but the result is a
– Longitudinal study of males with very detailed information on a variety of occupational and other health risks and outcomes
• Clear value of retaining and maintaining materials to study– Health effects of herbicides/dioxin in veterans– Other aspects of military health and
environmental and occupational exposures– Chronic disease risks– Normal aging
Consent to Use Records and Materials
Response
Comparison
N (%)
Ranch Hand
N (%)
Total
N (%)
AO & Health
AO only
Do not use
Other
Total
1,138 (96.9)
23 (2.0)
11 (0.9)
2 (0.2)
1,174
731 (94.1)
32 (4.1)
11 (1.4)
3 (0.4)
777
1,869 (95.8)
55 (2.8)
22 (1.1)
5 (0.3)
1,951
Making Data and Materials Available to Researchers
• Separately consider– A. Logistics and costs of maintenance of
materials– B. Costs of further research using these
materials• If data and material were available to
researchers, NIH and other research funders could support research using it through established programs