DOD.030325b "The design and implementation of surveillance systems to generate valid epidemiological data on deployed forces." Testimony by Manning Feinleib, MD, DrPH Johns Hopkins Bloomberg School of Public Health Baltimore, MD 21205 Fax: 410-614-9314 Hearings Before the Committee on Government Reform on Protecting the Health of Deployed Forces: March 25, 2003 2:00pm Rayburn Building Room 2247 Thank you, Mr. Chairman. 2 I am Manning Feinleib, Professor of Epidemiology at the Johns Hopkins Bloomberg School of Public Health. I was formerly Director of the National Center for Health Statistics at CDC and Associate Director for Epidemiology and Biometry at the National Heart, Lung, and Blood Institute of NIH. I am a member of the Institute of Medicine and have served on a recent IOM Panel on Gulf War and Health. Today I would like to discuss some aspects of the design and implementation of surveillance systems needed to generate valid epidemiological data on deployed forces. Following the 1991 Gulf War many groups became concerned about the health of the deployed forces. Several research studies confirmed the impression of the veterans that they were experiencing a variety of symptoms at higher rates than the general population (Joseph 1997, Joellenbeck 1998, Murphy 1999, Kang 2000). However, the studies were hampered by a lack of data on the base-line health of the veterans, lack of objective data on post-deployment health status, and inadequate data on exposures during deployment. Acting on the advice of numerous committees and task forces, and directives from Congress (PL 105-85 Sec. 765.) and from the National Science and Technology Council (NSTC 1998), DoD established several programs to improve the health of the military, veterans, and their families. DoD also requested the Institute of Medicine to evaluate these efforts and several extensive reports were produced providing detailed comments and numerous recommendations. (IOM 1996, 1998, 1999a, 1999b, 2000) Recently, analyses of the data generated from these efforts have begun to appear (MSMR 2002a, 2002b). It is my overall impression that although some initial steps have been taken to carry out this important mandate, implementation has been fragmented and little worthwhile data will be forthcoming from the forms currently used for pre- and post-deployment health assessment. As used by epidemiologists and public health workers, surveillance is a process for monitoring the health status of defined populations by collecting, analyzing, interpreting, and disseminating information about the occurrence of diseases in these populations. The various expert committees have been unanimous in recommending that the type of surveillance most suitable for studying emerging health problems in deployed forces is the prospective cohort study. At the time of deployment and immediately upon returning from deployment, a roster of all deployed personnel would be obtained and their baseline health status would be ascertained by means of standardized questionnaires and interviews supplemented with medical examinations and laboratory studies where indicated. During the period of deployment, data would be obtained on potential hazardous exposures and circumstances that may predispose the troops to future health problems. A tracking system would determine ensuing health events among all of the cohort members as early as possible. Procedures would be in place to verify diagnoses 3 and make referrals to appropriate health care facilities. In order to identify and determine the impact of specific exposures, various comparison groups would be assembled concurrently and followed in a similar manner to the deployed personnel. Congress has already mandated this tracking system in the National Defense Authorization Act of 1998 (PL 105-85 Sec. 765). More detailed descriptions of the tracking system and strong recommendations to implement such longitudinal cohort surveillance was made by the IOM Committee on Measuring the Health of Persian Gulf Veterans (IOM 1999a) and the IOM Committee on Strategies to Protect the Health of Deployed U.S. Forces (IOM 2000), chaired by Dr. John Moxley. The Committees recognized the great challenge this presented and that it would require the collaboration and commitment of both the VA and DoD, and possibly other agencies. A key requirement for the success of this endeavor would be obtaining the continuing participation of the deployed personnel for many years after their deployment. The Committees emphasized that this approach could eliminate major problems that were encountered in trying to resolve many of the veteran health issues that arose following the Vietnam and Gulf Wars. I vigorously second this recommendation and urge that adequate direction and resources be provided to implement it effectively. From an epidemiological perspective, cohort surveillance in the military setting offers some formidable challenges but also unique opportunities. I would like to go over some of these in the next few minutes. 1. Purposes of a surveillance system for deployed forces. In designing a surveillance system it is desirable to start with a clear concept of the purposes of the system, what questions it will be used to answer, and what are the population and subgroups of interest. There are many parties concerned about the health of veterans and the purposes for and questions to be addressed by the surveillance of deployed personnel are therefore many and varied. For some of these purposes it may not be necessary to track all of the deployed personnel and appropriate samples of the population may provide desired information in a more efficient and timely manner. Basically the purposes of surveillance include the following elements: 1. To ascertainment health status immediately before and after deployment. 2. To document exposures to known or potential hazards. 3. To provide an opportunity for personnel to express concerns about their health and receive early medical attention. 4. To ascertain health events after discharge, including physical, mental, and reproductive effects. The experience of Viet Nam and the Gulf War indicate that potential effects may be both subtle and complex, and may take several years to manifest themselves. 5. To compare the nature and frequency of health events among groups with different exposures. 5 |