Air Force Health Study (Ranch Hand) Research Assets

Type: Epidemiological Study
Topics: Military and Veterans Health, Biomedical and Health Research
Board: Medical Follow-Up Agency

Activity Description


In 1979, the US Congress directed that an epidemiologic study be conducted to evaluate the frequency and nature of adverse health effects that might be related to exposure to “Agent Orange” and other military herbicides used during the Vietnam conflict. The effort—formally called the Air Force Health Study (AFHS) and informally referred to as the Ranch Hand Study—involved Operation Ranch Hand veterans and a comparison group of Air Force personnel who served in Southeast Asia but who were not involved in herbicide spraying operations. 

After the Study concluded, the Congress directed that its research assets be transferred to the custodianship of the Institute of Medicine (IOM). A later Public Law (110-389) instructed the Department of Veterans’ Affairs to work with the IOM to make the AFHS assets available to scientific investigators for scientifically peer reviewed pilot and other research studies.

Access to the AFHS Assets for Novel Research

Most of the AFHS information collection effort was focused on the morbidity component of the study, where exceptionally detailed data gathering took place. The initial physical examination and surveying of AFHS subjects was conducted in 1982 and subsequent cycles were conducted in 1985, 1987, 1992, 1997, and 2002. Physical examinations included spirometry, chest X rays, electrocardiograms (ECGs), dermatology and peripheral vascular examinations, neurological assessments, psychological testing, and many other clinical endpoints. A laboratory component of blood draws, urine and semen collections, skin and fat biopsies, and stool smears was also part of the physical examinations. More than 86,000 biologic specimens were collected over the course of the study; approximately half of these are serum. Blood was collected in all six cycles and serum stored; semen was obtained in the first cycle and urine in first three cycles. Adipose tissue was collected during the fifth examination cycle and, in the sixth cycle, whole blood was also stored. Serum is available for all six cycles for 1,204 subjects. 

Subjects were asked to provide their medical records, as well as those of their children (up to age 17), their present partner, and any previous partner. Questionnaires eliciting information on education, employment, income, marital and fertility history, child and family health, health habits, recreation, leisure, and physical activities, toxic substances exposure, military experience, and wartime herbicide exposure were also administered. Although 2,758 subjects participated in at least one cycle exam, information and biospecimens are available only for those 2,210 individuals who consented to have their materials transferred to IOM custodianship and used in research. Reproductive data were gathered and coded on 9,921 conceptions and 8,100 live births. The mortality component of the study followed over 20,000 Vietnam War-era veterans with service in Southeast Asia for nearly 25 years.

Details on the original AFHS, its research subjects, and the data and biospecimens collected may be found in the Institute of Medicine report Disposition of the Air Force Health Study, which may be freely downloaded from the National Academies Press website.

While the AFHS was intended to evaluate the health effects of herbicide and dioxin exposure, the data and biospecimens may be used for studies of other issues, including but not limited to:

  • Long-term health outcomes and changes in biomarkers, DNA methylation, or other measures with regard to response or susceptibility to health endpoints; 
  • Using biospecimens for early detection, identification of therapeutic targets, and/or disease response markers; 
  • New statistical analyses, methods, and models of exposures on health effects; 
  • Environmental, leisure, and occupational exposures on health outcomes; 
  • Health impacts of aging;  
  • Reanalysis of outcomes examined by the AFHS using different assumptions and approaches than have been applied to date; 
  • New analyses can be performed on the existing medical records and other study data that examine questions that were not addressed as part of the AFHS; 
  • New assays and technologies permit biomarker, genotype, and other analyses that were not possible during the term of the original study; 
  • Expansion of the study’s period of analysis through follow-up of the cohorts using publicly available information; and
  • Additional follow-up of health and medical outcomes in AFHS participants. 

Proposals for innovative uses of the materials for research to further the goals of understanding the determinants of health and promoting wellness are encouraged. Access to the materials is open to qualified researchers whose use of the AFHS assets is deemed appropriate by an IOM committee. The first step to applying for to access the AFHS data or specimens is to submit a brief letter of intent that outlines a proposed area[s] of research on the AFHS assets, and can be submitted by clicking here. If approved, the committee will invite the investigator to submit a full proposal. The committee evaluates the scientific merit of proposals, which will also be subject to review by both the investigator’s institution and the National Academies’ institutional review boards.  Details on the application process can be found in the Request for Proposal.


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