Health Surveillance Mechanisms Used by Armed Forces Worldwide

Health surveillance is an essential tool in monitoring health in an armed force and in helping to protect the health of service personnel. This study used a literature search and direct contacts with individual countries to identify and evaluate health surveillance mechanisms used by armed forces worldwide. The study identified several health surveillance mechanisms ranging from periodic health assessments of personnel to complex databases of medical data linked to demographic and other supporting data. Essential elements of an effective health surveillance system are outlined, including the requirement that systems are adequately supported and allow the routine monitoring of health at the population level consistently throughout an armed force and consistently during times of peace and during operations. Areas for further research and development include linking of data on hazardous exposures, jobs and the locations of personnel with medical data, and the follow-up of personnel beyond their military service.

Introduction

Health surveillance and health screening, for which there is evidence of benefit, form an integral part of any effective health care system and should allow "... the routine, systematic collection, analysis, interpretation and reporting of standardized, population-based data for the purposes of characterizing and countering threats to a population's health, well-being and performance."1 This needs to be closely integrated with the timely dissemination of these data to decision makers and, to be effective, must be directly linked to preventive action.2

In civilian industry, health surveillance programs play an important role in monitoring trends in illness, injury, and exposure to workplace hazards and in helping to identify areas where preventive action can help reduce the impact of disease. Health surveillance in the military setting poses particular challenges due, for example, to a large mobile workforce, differences in operational practices between services, and a broad range of hazards to which personnel may be exposed. Developing an effective military health surveillance system requires multidisciplinary involvement not only of medical units but also, for example, of occupational and environmental health professionals and personnel departments. This multidisciplinary involvement is necessary to collect, collate, and organize the required data, which include demographic data, data that identify locations, jobs or tasks undertaken by individuals, and data on exposures of personnel to occupational and environmental hazards.

In recent years, the challenge of developing a comprehensive military health surveillance system has begun to be addressed by several armed forces worldwide, particularly in light of experiences following the 1990-1991 Gulf War conflict and operations in the former Republic of Yugoslavia, where inadequate health, exposure, and associated records hampered the investigation of health concerns after these operations.3-6 As part of a wider research program on health surveillance, the United Kingdom Defense Science and Technology Laboratory commissioned a review of health surveillance systems used by armed forces worldwide, with a view to learning from the experience of other armed forces to inform the development of the United Kingdom Defense Medical Service's health surveillance capability (Institute for Environment and Health: An Objective Assessment of Existing and Planned Health Surveillance Mechanisms Used by Armed Forces Worldwide (unpublished report). The aim of the project was to identify and compare health surveillance mechanisms, processes, and methodologies, existing or planned, in armed forces worldwide and to evaluate their effectiveness and suitability for adoption or modification and incorporation by the United Kingdom Armed Forces. This article summarizes the types of mechanisms identified in the review and discusses the common elements necessary for an effective military health surveillance system.

Study Design

Information about the health surveillance systems used by armed forces worldwide was obtained through a literature search and by direct approaches to individual countries. The literature search consisted of a search of 12 online databases to identify published material on health surveillance mechanisms used in armed forces. It was conducted in May 2001 and was updated in December 2001 and was restricted to references published in the last 10 years for which an English title or abstract was available. Additional references were obtained through the review of the reference lists of those articles obtained, ad hoc searches of the Internet, and from individuals in the countries contacted. Direct contact was made with a number of non-United Kingdom armed forces to request unpublished material about each country's health surveillance system and to administer a questionnaire. The questionnaire was developed based on guidelines from the Centers for Disease Control and Prevention7 and a short pilot study conducted within the United Kingdom Armed Forces. Additionally, a workshop was held in January 2002, at which the preliminary findings of the review were presented and discussed by representatives of the United Kingdom and overseas armed forces, civilian industry, and academia; the workshop also considered essential elements for an effective military health surveillance system. The information gathered from the literature search, from individual countries and the workshop were used to develop an overall understanding of the health surveillance systems used by armed forces worldwide and to critically evaluate approaches used for military health surveillance.

In total, 31 countries or organizations were approached to be involved in the study between May 2001 and February 2002. Of these, 14 responded and were able to provide information about their health surveillance system and/or complete the questionnaire. An additional six countries responded but for several reasons information was not obtained; 12 countries or organizations made no response. One country and one organization for which published information was available were not contacted because of the lack of contact details. Table I summarizes the information obtained.

Results

The literature search and direct approaches to individual countries identified several health surveillance mechanisms used to varying extents by different armed forces. The health surveillance mechanisms identified have been categorized here into short-term and long-term mechanisms. Short-term health surveillance mechanisms are those mechanisms designed to identify short-term changes in the health of individuals or a population that may impact on manpower; long-term health surveillance mechanisms are those that enable more comprehensive health surveillance of a population over a longer time period. A number of countries operated more than one of these health surveillance mechanisms, which, combined, comprised their armed forces' health surveillance system. The mechanisms identified are described below and summarized in Table II.

Short-Term Health Surveillance Mechanisms

Periodic Medical Assessments

Most armed forces reported carrying out a prerecruitment and/or initial medical examination and periodic medical examinations thereafter. The interval between the examinations and the reason for them varied according to service, job, or task being undertaken, potential exposures, and the age of personnel. These examinations were mainly used as medical screening tools to ensure personnel were fit for duty and to detect health problems at an early stage. No armed forces reported routinely analyzing these data at the population level to identify population health trends, although the prerecruitment or periodic medical examination data have the potential to be used to provide a baseline with which to compare any subsequent changes in health.

Notifiable Disease and Condition Reporting

Many of the countries contacted had a notifiable disease and condition reporting system to identify cases of diseases or medical events of particular concern and to act as a trigger to implement preventive action. The systems identified were often based on, or closely linked to, national requirements for reporting notifiable diseases and conditions and usually required reporting to civilian and military authorities. The majority of systems were used during operations and during peacetime.

An example of a typical notifiable disease and condition reporting system is the Notifiable Condition Reporting System of the Australian Defense Force (ADF).8 The system covers all ADF personnel during peacetime, and operational deployments or while overseas and is based on a list of nationally notifiable diseases, with some additional ADF-specific notifiable conditions. When a notifiable condition is identified, it is reported to the civilian authorities and to the Defense Health Services Branch. On receipt, the Defense Health Services Branch enters the data into a database and use the data to monitor trends of notifiable conditions within the ADF, identify public health issues, define health priorities, and verify health threat assessments. Quarterly summaries of the data are disseminated to all ADF health care facilities and senior commanders via the ADF Quarterly Health Surveillance Report. Quarterly totals of notifiable disease reports are also used to update the Australian Disease and Environmental Alert Reporting System-a World Wide Web-based system that provides assessments of health threats in areas of operational importance.9

Pre- and Postdeployment Health Assessments

In addition to periodic medical examinations, many armed forces undertake pre- and postdeployment health assessments. These vary from a full medical assessment, such as those carried out in the Belgian Armed Forces, to a short questionnaire, like that administered in the U.S. Armed Forces. The purpose of these assessments is to ensure personnel are fit to deploy and to provide baseline data with which to compare postdeployment health status. The majority of the armed forces contacted appear not to have used pre- and postdeployment health assessment data to assess changes in health at the population level. Indeed, only one published analysis at a population level was identified, that of pre- and postdeployment health assessments of U.S. service personnel.10 This analysis looked at 55,085 service members who had completed a pre- and postdeployment health assessment form between January 1, 2000 and May 31, 2002. The analysis found that the majority of those deploying (61.7%) reported the same health status on their predeployment health assessment form as on their postdeployment health assessment form. Of the remainder, almost identical proportions reported an improvement or decline in health status. Additionally, approximately 4% of personnel indicated concerns about possible hazardous exposures. The U.S. Institute of Medicine, when assessing strategies to protect the health of U.S. Armed Forces, recommended that unless necessary for military purposes, pre- and postdeployment health assessments should be replaced by a regularly administered health questionnaire.11 One armed force, the New Zealand Defece Force, has decided to replace its pre- and postdeployment health assessments with an annual questionnaire and discretionary medical examination, partly because of the difficulty in defining what constitutes a deployment.

Disease and Nonbattle Injury Reporting

Disease and nonbattle injury (DNBI) reporting systems record data on a service member's first and subsequent attendance at a medical treatment facility, their diagnosis, and the subsequent impact on manpower. Recording of DNBI events was widely used among the countries contacted; the systems used included the British Army's J97 system, EPINATO, the Joint Chiefs of Staff DNBI Report, or a modified variant of one of these systems. Most of the armed forces contacted used a DNBI reporting system while on deployments or operations requiring its implementation, such as NATO operations, as a means of assessing the impact of DNBI on manpower. However, DNBI reporting systems are also used during peacetime by some armed forces (e.g., the British Army, the Israel Defense Force [IDF]), and the Royal New Zealand Navy).

DNBI reporting systems have been successfully implemented during operations in the former Republic of Yugoslavia and during a U.N. mission in Haiti.12-14 The systems were found to be easy to use, unobtrusive, and readily accepted by medical personnel; they were able to show that operations, such as Joint Endeavor and Joint Guard in the former Republic of Yugoslavia, were relatively safe and healthy operations.12 Experience of using DNBI reporting systems has, however, identified a number of limitations of the systems. In particular, the health event categories used (e.g., "Intestinal Infectious Diseases" or "Dermatological Conditions") are broad and do not readily facilitate identification of the initiatives and actions required to tackle the health problems. In addition, a high percentage of health events may be recorded in categories such as "Injuries-Other," thus limiting the usefulness of a large proportion of the data collected. For example, between July 1996 and January 1997, 32.7% of days lost during Implementation Force in the former Republic of Yugoslavia were recorded as "Injuries-Other" or "Diseases-Other."13 Finally, data are also reported as aggregated returns and are not differentiated according to sex, age, job or task, or other factors; this limits the identification of population subgroups more at risk from specific health events and, in turn, may limit the ready identification of appropriate interventions. Nevertheless, it should be noted that DNBI reporting is the only example of a health surveillance mechanism that has been used in joint forces operations, such as NATO operations, and that allows direct DNBI rate comparisons between armed forces from different countries.

Long-Term Health Surveillance Mechanisms

Health Surveillance from Electronic Medical Records

The most advanced and complex systems identified were those based on electronic medical records. These seek to link medical data with other databases, such as personnel or exposure databases, to create a comprehensive database for health surveillance. Only two armed forces were identified (The Netherlands Armed Forces and the U.S. Armed Forces) that have such a system in place, although such systems are planned or are being implemented by the ADF, the Canadian Forces, the IDF, and the United Kingdom Armed Forces.

The most well-developed electronic medical record-based health surveillance system identified was the Defense Medical Surveillance System (DMSS) of the U.S. Armed Forces.15 This system receives, collates, and integrates personnel data, medical data, serological data, and deployment data from all of the U.S. armed services into a single relational database, from which reports are generated and published regularly in the Medical Surveillance Monthly Report. The system captures primary and secondary health care data from military medical treatment facilities and U.S. nonmilitary medical treatment facilities at which service personnel are treated. With such a large system, there are inevitably some gaps in coverage and completeness of records. For example, data are not captured from U.S. Naval hospital ships. However, these gaps have been acknowledged and there are plans to remedy some of them in the future.

Important considerations regarding the use of such health surveillance systems include the accuracy and validity of the data. Several of the systems identified had procedures to ensure consistent and accurate data entry, for example, by having programs that ensure data fields are completed and that the data entered are consistent with the field type.15 However, none of the armed forces with an electronic medical record-based health surveillance system have procedures or plans to validate the reliability of the data entered into the systems. Another important consideration regarding the use of electronic medical record-based health surveillance systems is the ease with which the data can be analyzed. The ease of analysis of data has been addressed in DMSS with the development of the Defense Medical Epidemiology Database.15 This is a data analysis tool that enables users to query a subset of the data within DMSS over the Internet. In other systems, such as the Royal Netherlands Navy electronic medical record system, Geneeskundige Informatie Functie Koninklijgke Marine, analysis of the data in the system is not always as user-friendly, as separate query programs have to be written each time a new nonroutine analysis is required.

Health Questionnaires

Several armed forces use periodic health questionnaires as a health surveillance tool. These allow the ongoing, routine, and systematic collection of health-related data in a relatively cost-effective and efficient manner. Armed forces in which routine health questionnaires are being used or are planned include the Canadian Forces, the IDF, the New Zealand Defence Force, and U.S. Armed Forces. In particular, the IDF conducts an ongoing, population-based health surveillance survey of a representative sample of 5% of all recruits and discharged soldiers, including taking a serum sample. The survey has resulted in many reports that have provided key input for military and national preventive health strategies.16-19 Outcomes from questionnaires used by other armed forces have also been published. For example, the U.S. Armed Forces published an analysis from the Department of Defense (DoD) Survey of Health Related Behaviors and the Canadian Forces published an analysis of their Health and Lifestyle Information Survey.20,21 These questionnaires have proved effective in providing information on indicators of health and less well-defined health outcomes, such as mental health and stress, and have helped inform decision and policy making. Important considerations when using questionnaires for health surveillance are that the questionnaires need to be adequately validated and that the resulting data need to be fully analyzed at a population level.

Disease and Death Registries

Several countries have developed registries for the purpose of conducting surveillance on specific health endpoints and, although few reported it as a health surveillance mechanism as such, many countries maintain data on active duty deaths. An example of two such registries are the DoD Birth and Infant Health Registry, which aims to provide systematic surveillance of births to DoD health care beneficiaries and to estimate the prevalence of birth defects, and the DoD Medical Mortality Registry, which collects detailed data on all active duty deaths with a view to analyzing the data to identify factors involved in the deaths and prevent further occurrences.22,23 The Birth and Infant Health registry, in particular, has been validated and shown to be capturing the majority of birth defects occurring in children born to service members on active duty and their dependants and to retirees and their dependants.24

Follow-Up beyond Military Service

Follow-up of personnel after they leave the armed services was also considered. No country contacted had developed a comprehensive routine method for following up personnel after they leave the armed forces. However, several countries are following up limited cohorts, such as the cohorts of veterans of the 1990-1991 Gulf War conflict being studied by the Australian, Canadian, and United Kingdom Armed Forces, and the Canadian Forces have plans to link all post-1990 service members to their national cancer and mortality databases. The U.S. Armed Forces are also developing several initiatives to address this issue; in particular, the Federal Health Information Exchange is being developed, which will facilitate the transfer of medical information between the DoD and the Department of Veteran's Affairs, thereby facilitating monitoring of health beyond military service.25 The U.S. Armed Forces have also begun the prospective follow-up of 140,000 personnel, as part of the Millennium Cohort study, with the aim of evaluating the influence of military service on the health of service personnel over a period of up to 21 years.26 The study will provide a basis for comparing health status between deployed and nondeployed personnel and will provide a foundation upon which other routinely captured medical and deployment data may be built to answer future health-related questions.

Discussion

Health surveillance is an essential tool for monitoring ill health in an armed force to help protect the health of service personnel. A variety of mechanisms have been identified for health surveillance in armed forces worldwide. From these, a number of essential elements have been identified that contribute to an effective health surveillance system: the importance of the system should be recognized at senior command levels and should be under-pinned with well-defined policy and objectives, clear lines of responsibility, and with adequate resources; the system should facilitate the routine monitoring of health at the population level; the system should be implemented and applied consistently throughout the services within the armed force concerned, in peacetime and during operations and deployments; the system should have adequate linkages to data on the demographic characteristics of the population concerned, and to information on their location, jobs or tasks, and exposures to potential hazards; the system should follow-up personnel beyond their military service; the system should be supported and coordinated by dedicated and appropriately qualified staff; the data collected should be analyzed on a routine basis and reported in an appropriate format to senior commanders and to those collecting the data; and the outcomes of the health surveillance system should be used to inform policy and, where appropriate, lead to action to prevent further ill health.

A number of the systems identified fulfill, or have made some progress toward fulfilling, some of these essential elements. For example, in many armed forces there is high-level commitment to health surveillance, with clear policy and lines of responsibility that have resulted in health surveillance systems that appear relatively successful. These essential elements are probably most successfully addressed in electronic medical record-based health surveillance systems, such as DMSS, where ready access to medical data, and corresponding demographic data, facilitate analysis of the data, which are subsequently reported and distributed widely.

None of the systems identified, however, met all of the suggested elements of an ideal system. In particular, for several of the mechanisms identified, such as periodic health screening and some pre- and postdeployment health assessments, there was no reported analysis of the data at a population level. Although useful at the individual level, the lack of population level statistics limits the interpretation and use of these data.

Thus far, no systems identified have comprehensively addressed the issue of adequately linking health data with other information such as exposure data, job or task information, and location data, although some systems, such as DMSS, have made considerable progress, particularly in linking demographic and medical data. The linkage of health data with data on demographics and exposures is essential in order that groups experiencing higher incidence and/or prevalence of a particular health outcome can be identified, and so that factors associated with the particular health outcomes can be elicited thus facilitating the identification and implementation of preventive measures. This is an area requiring further research and development.

The follow-up of service personnel beyond their military service also remains an area for further research and development. This is important as some health endpoints may only become manifest after a service member has left the forces sometimes many years following the causative exposure(s). The Millennium Cohort Study is an initiative that should help address some of these questions, but the development of methodologies for regular and routine follow-up of service personnel is still needed.

Conclusions

Health surveillance among armed forces worldwide has received much attention over the past decade. As a result, a number of systems have been developed to monitor the health of service personnel and to limit the impact of ill health. These vary considerably in their scope and complexity, but nonetheless have proven useful in better understanding and protecting the health of armed forces. Systems based on electronic medical records have demonstrated some of the potential such approaches hold for future military health surveillance. Development of and experience of using such systems should bring further enhancements to the health surveillance capabilities and ultimately the health of armed forces worldwide.

Acknowledgments

We thank Mr. Neal Smith and Mr. Bob Ferguson of the Defense Science and Technology Laboratory and the Health Surveillance Steering Group of the Surgeon General's Department for their support throughout the project. We also thank those we contacted and who participated in the project, those who kindly commented on this article, and Mrs. Elaine Bottrill and Mrs. Dena Williamson for their administrative support.

This study was funded by the Ministry of Defence, via the Defence Science and Technology Laboratory, Contract RD013-920815.

[Reference]

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[Author Affiliation]

Guarantor: Lesley Rushton, PhD

Contributors: Alexander C. Capleton, MSc; Hemantha Wickramatillake, MedSc; Lesley Rushton, PhD

[Author Affiliation]

Medical Research Council Institute for Environment and Health, University of Leicester, 94 Regent Road, Leicester, LE1 7DD, United Kingdom.

This manuscript was received for review in July 2003 and accepted for publication in January 2004.

Reprint & Copyright � by Association of Military Surgeons of U.S., 2004.