miologic studies of veterans could yield valuable information. That is true especially because diseases of aging could emerge as the population grows older, and as a new exposure-reconstruction model is developed and validated.
The Air Force Health Study (AFHS) is an epidemiologic study whose purpose is to determine whether exposure to the herbicides used in Vietnam might underlie any adverse health conditions observed in a cohort of Air Force personnel (termed the Ranch Hands) who conducted aerial spray missions (Operation Ranch Hand). A baseline morbidity study of them and a matched comparison cohort was conducted in 1982, and there were follow-up assessments in 1985, 1987, 1992, and 1997. In accordance with the study protocol, one additional assessment is under way and will be completed in April 2003. A final report will be issued in early 2005 (personal communication, Joel Michalek, Brooks Air Force Base, September 17, 2002).
The AFHS is one of the few primary sources of information on the health of Vietnam veterans known to be exposed to Agent Orange and other herbicides. The study is coming to its scheduled end as the cohorts are reaching the age at which several health outcomes of interest may be expected to manifest, such as cancers and diseases related to aging. The committee recommends continuing the study past its planned completion date to enable further study of those diseases. Given the increased incidence of such diseases as amyotrophic lateral sclerosis, Parkinson's disease, prostatic cancer, and brain cancer in aging populations and the increasing age of the Vietnam-veteran cohort, research should specifically examine those diseases in the Vietnam veterans. Such studies should be conducted with an appropriate control population. Similarly, continued study of other exposed cohorts (for example, the cohort studied by the National Institute for Occupational Safety and Health) could also provide information on diseases of aging.
The committee also recommends retaining and maintaining medical records and samples on the AFHS cohort so that—with proper respect for the privacy of the study participants—they can be available for future research. The federal government should examine how the various forms of data and specimens collected in the course of the AFHS might be maintained and what form of oversight should be established for their future use. Any extension of the research or future use of the records would, of course, have to have the full knowledge and consent of the AFHS population and respect for the privacy of the participants. The committee's judgment is that continued research on the health of the Ranch Hands and comparison veterans is likely to yield important information on the determinants of health and disease in those who served in Vietnam and perhaps in their offspring.