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Biomedical subjects

Gary D Gackstetter

Publications and source records attributed to Gary D Gackstetter.

18 recordsLinked to original sources
PubMed2006

Millennium Cohort: enrollment begins a 21-year contribution to understanding the impact of military service.

OBJECTIVE: In response to health concerns of military members about deployment and other service-related exposures, the Department of Defense (DoD) initiated the largest prospective study ever undertaken in the U.S. military. STUDY DESIGN AND SETTING: The Millennium Cohort uses a phased enrollment strategy to eventually include more than 100,000 U.S. service members who will be followed up through the year 2022, even after leaving military service. Subjects will be linked to DoD and Veterans Affairs databases and surveyed every 3 years to obtain objective and self-reported data on exposures and health outcomes. RESULTS: The first enrollment phase was completed in July 2003 and resulted in 77,047 consenting participants, well representative of both active-duty and Reserve/Guard forces. This report documents the baseline characteristics of these Cohort members, describes traditional, postal, and Web-based enrollment methods; and describes the unique challenges of enrolling, retaining, and following such a large Cohort. CONCLUSION: The Millennium Cohort was successfully launched and is becoming especially relevant, given current deployment and exposure concerns. The Cohort is representative of the U.S. military and promises to provide new insight into the long-term effects of military occupations on health for years to come.

Adolescent↗
PubMed2006

Understanding the effect of deployment on the risk of fatal motor vehicle crashes: a nested case-control study of fatalities in Gulf War era veterans, 1991-1995.

Motor vehicle crashes (MVCs) are an important cause of morbidity and premature loss of life among military personnel during peacetime and particularly following combat. A nested case-control study of fatal MVC occurring between 1991 and 1995 was conducted in a cohort of Gulf War era veterans. Cases were validated MVC deaths in the Fatality Analysis Reporting System. Controls were selected using risk set sampling by gender and year of case ascertainment in a 10:1 ratio. Preliminary results, consistent with previous reports of increased fatal MVC risk among returning combat veterans, showed a crude odds ratio of 1.45 (95% confidence interval 1.27-1.65). Multivariable logistic regression modeling was used to identify important independent predictors, as well as to quantify the influence of deployment on a risk profile for fatal MVC. Because of significant interaction between deployment and inpatient diagnosis of substance abuse, the final model was stratified by deployment status. Results suggest that demographic, military, and behavioral characteristics of deployed healthy warriors are similar to the risk profile for fatal MVC. In addition to young, single, high school-educated, enlisted male personnel, those who served during times of ground combat, particularly in infantry, gun crews, or seamanship occupations, should be targeted for preventive interventions.

Accidents, Traffic↗
PubMed2006

Fatal motor vehicle crashes among veterans of the 1991 Gulf War and exposure to munitions demolitions at Khamisiyah: a nested case-control study.

BACKGROUND: A proposed explanation for the observed higher risk of fatal motor vehicle crashes (MVC) among 1991 Gulf War-deployed veterans is neurocognitive deficits resulting from nerve agent exposure at Khamisiyah, Iraq. Our objective was to assess any association between postwar fatal MVC and possible nerve agent exposure based on 2000 modeled plume data. METHODS: Cases were defined as MVC deaths with a record in the Department of Transportation Fatality Analysis Reporting System through 1995. Cases (n = 282) and controls (n = 3,131) were derived from a larger nested case-control study of Gulf War-era veterans and limited to Army, male, deployed personnel. Exposure and cumulative dose by case-control status were analyzed using multivariate techniques. RESULTS: Exposure status was not associated with fatal MVC (OR 0.96, 95% CI 0.72-1.26), nor were tertiles of cumulative dose. CONCLUSIONS: Findings do not support an association between possible exposures at Khamisiyah and postwar fatal MVC among Gulf War veterans.

Accidents, Traffic↗
PubMed2006

Motor vehicle fatalities among Gulf War era veterans: characteristics, mechanisms, and circumstances.

OBJECTIVES: Our objective was to describe fatal motor vehicle crashes (MVC) among veterans of the 1991 Gulf War era and to compare the distribution of crash and individual characteristics between those deployed to the Gulf War (GWV) and those not deployed (NDV). METHODS: We compared individual characteristics, crash mechanisms, and crash circumstances between 765 GWV and 553 NDV who died from MVC within the first five years of the war, between May 1991 and December 1995. RESULTS: Overall, GWV and NDV who died from a MVC were more likely to be enlisted males (97%), 21-30 years old (72%), have a high school education or less (91%), drive a passenger car (52%), and not use restraints (60%). The overall annual rate of motor vehicle fatalities for GWV (23.6 per 100,000; 95% confidence interval: 21.9-25.3) was significantly greater than the rate for NDV (15.9, 95% CI: 14.6-17.3). GWV with the highest motor vehicle fatality rates include males (24.8, 95% CI: 23.0-26.6), 17-20 year olds (105.0, 95% CI: 78.2-138.1), and those not married (27.3, 95% CI: 25.1-30.1). Adjusting for differences in age distribution across GWV and NDV did not account for the difference in rates. Characteristics of MVC fatalities that were over-represented among GWV include serving as regular active duty (p = 0.001), having a high school education or less (p = 0.01), being involved in a single-vehicle crash (p = 0.008), and dying within the first hour following the crash (p = 0.004). Also, we identified a greater proportion of alcohol-related crashes among GWV during the late night and early morning hours. CONCLUSIONS: The highest rates of motor vehicle fatality among young, single males in the military mirror the experience of the general population. Further research is necessary to determine modifiable risk factors that can be targeted for specific interventions and whether the elevated late night alcohol-related crash rate among GWV is an effect of deployment or an inherent population bias among those selected for operational deployments.

Accidents, Traffic↗
PubMed2005

Assessing the potential health impact of the 1991 Gulf War on Saudi Arabian National Guard soldiers.

BACKGROUND: There has been considerable publicity that the 1991 Gulf War may have caused a wide array of health problems in military personnel. Although post-war health outcomes have been studied in US, British, Canadian, Danish, and other deployed troops, this issue has not been previously evaluated in coalition forces native to the Gulf region. METHODS: A collaborative team of US and Saudi health researchers was assembled, data sources evaluated, and hospitalizations among Saudi Arabian National Guard (SANG) soldiers between 1991 and 1999 analysed. Multivariate modelling was used to evaluate differences between 8342 soldiers exposed to combat at Al Khafji and a comparison group of 7270 soldiers in the Riyadh area. RESULTS: Among 15 612 SANG soldiers, we identified 148 with at least one hospitalization over the 9 years following the war. The adjusted rate of hospitalization was higher in the combat-exposed group (risk ratio (RR) = 1.80, 95% confidence interval (CI) 1.25-2.59). No unusual patterns of diagnoses were found and, because the overall number of hospitalizations was low, the absolute difference in risk was found to be very small. CONCLUSIONS: This is the first reported epidemiological investigation of post-war hospitalizations among coalition forces native to the Gulf region that participated in the 1991 Gulf War. A very small increase in hospitalizations was identified in SANG soldiers exposed to combat at Al Khafji. However, because of data limitations, the clinical relevance of this finding should be interpreted with caution. Future collaborative studies to better understand the health effects of deployment should be encouraged.

Adolescent↗
PubMed2005

Leveraging existing databases to study vehicle crashes in a combat occupational cohort: epidemiologic methods.

BACKGROUND: The US military is a large, well-defined occupational cohort offering tremendous opportunities to study risk factors for important health outcomes. This article describes our nested case-control methods to evaluate risk factors for fatal motor vehicle crashes (MVC) within all Service branches in a 1991 Gulf War era cohort. METHODS: We identified 1,343 cases of fatal MVC between 1991 and 1995 that were also included in the Department of Transportation's Fatality Analysis Reporting System database and, using risk set sampling, selected 13,430 controls. Our final analytic dataset consisted of 980 male driver cases and 12,807 controls linked to multiple databases. RESULTS: Cases were disproportionately younger, less educated, not married, enlisted, and deployed to the Gulf War, compared to controls. CONCLUSIONS: The ability to leverage multiple databases to study risk factors for fatal MVC is clearly advantageous and could eventually lead to the reduction of fatalities in similar occupational cohorts.

Accidents, Occupational↗
PubMed2005

Saudi Arabia-United States collaboration in health research: a formula for success.

The aim of this article is to share our experiences from an international collaborative effort to study health outcomes among Saudi Arabian National Guard (SANG) soldiers following the 1991 Gulf War. By paying particular attention to distinct social and religious customs, geopolitical differences, and unique aspects of the health care system, we achieved a successful international collaboration in health research.

Cultural Characteristics↗
PubMed2005

Aeromedical evacuations from Operation Iraqi Freedom: a descriptive study.

OBJECTIVE: To describe health patterns in evacuated military members during Operation Iraqi Freedom (OIF) and utilize demographic, diagnostic, and pre- and postdeployment health information to understand the utility of data collected for aeromedical evacuations. METHODS: We conducted a descriptive analysis of U.S. evacuees from 2003 using data from the U.S. Transportation Command's Regulating and Command & Control Evacuation System and the Defense Medical Surveillance System. RESULTS: The typical patient was an Army male under the age of 29 requiring orthopedic or surgical care. Disease/nonbattle injuries were six times as common as battle injuries and 94% were classified as routine evacuees. Eighty-six percent had health data available in the Defense Medical Surveillance System. Two thirds had pre- and/or postdeployment questionnaire data. CONCLUSIONS: Combining data sources increases our understanding of disease patterns in deployed troops. Targeted preventive interventions can then be implemented. Changes in the U.S. Transportation Command's Regulating and Command & Control Evacuation System database can improve its utility as an epidemiological tool.

Adult↗
PubMed2004

After more than 10 years of Gulf War veteran medical evaluations, what have we learned?

Since the 1991 Gulf War, more than 10 years and 1 billion dollars of health evaluations and research have been invested in understanding illnesses among Gulf War veterans. We examined the extensive published healthcare utilization data in an effort to summarize what has been learned. Using multiple search techniques, data as of June 2003 from four different national Gulf War health registries and numerous hospitalization and ambulatory care reports were reviewed. Thus far, published reports have not revealed a unique Gulf War syndrome nor identified specific exposures that might explain postwar morbidity. Instead, they have demonstrated that Gulf War veterans have had an increase in multi-symptom condition, injury, and mental health diagnoses. While these diagnoses are similar to those experienced by other comparable military populations, their explanation is not fully understood. New strategies to identify risk factors for, and to reduce, such postdeployment conditions are summarized.

Ambulatory Care↗
PubMed2004

The postwar hospitalization experience of Gulf War veterans participating in U.S. health registries.

In response to concerns that Gulf War veterans were experiencing increased morbidity resulting from wartime exposures in the Gulf War, the Department of Veterans Affairs and the Department of Defense (DoD) initiated clinical registries to provide systematic health evaluations for self-referred Gulf War veterans. The authors used Cox's proportional hazard modeling with data from all DoD hospitals to estimate the probability of hospitalization resulting from any cause, resulting from diagnosis in a major diagnostic category, and resulting from a specific diagnosis of interest. After adjusting for other risk factors, registry participants were 1.43 times more likely to have a postwar hospitalization than registry nonparticipants (95% confidence interval, 1.40-1.46). These findings support the hypothesis that registry participants were more likely to experience postwar morbidity than veterans who chose not to enroll in the health registries.

Adult↗
PubMed2004

Variables associated with attrition from Uniformed Services University of the Health Sciences Medical School.

Attrition among medical students is a concern for the institution, the individual, and the profession. Disenrollment has an impact on the institution, in terms of academic reputation and resources expended, and the individual, in terms of self-esteem, personal finances, and opportunity costs. This study summarizes the results of an epidemiologic study of student attrition conducted at the only federal medical school in the United States--the Uniformed Services University of the Health Sciences in Bethesda, Maryland--and describes the association between demographic and selected quantitative variables for those students who graduated or remained enrolled and those who disenrolled. Both sex (female) and a decelerated curriculum were predictive of attrition in this medical student population. The records of the students who left Uniformed Services University of the Health Sciences without graduating were examined to ascertain the presence of noncognitive issues surrounding disenrollment; over one-half of the students who disenrolled left voluntarily and for nonacademic reasons.

Adult↗
PubMed2003

Molecular genetic analysis of 675 group A streptococcus isolates collected in a carrier study at Lackland Air Force Base, San Antonio, Texas.

Contemporary molecular genetic analysis methods have not been used to study large samples of carriage isolates of group A Streptococcus. To determine the emm types causing asymptomatic carriage and pharyngitis in a closed population, we analyzed 675 isolates recovered from a population-based surveillance study of 10,634 recruits at Lackland Air Force Base, Texas, during 4 months in 1993-1994. Strains with emm1 and emm6 alleles accounted for only 22% of the isolates recovered from asymptomatic recruits at entrance to training. However, these 2 emm types caused 69% of the pharyngitis cases identified during training and represented 51% of the isolates recovered from the throat on exit from training. Sequence analysis of the hypervariable sic gene documented that distinct emm1 subclones disseminated in specific training groups called flights. The preferential increase in the prevalence of emm1 and emm6 isolates during the 6-week training period indicates an enhanced ability of these strains to disseminate and cause disease in this population.

Alleles↗
PubMed2003

Identifying new diseases and their causes: the dilemma of illnesses in Gulf War veterans.

Since the Gulf War, investigation continues of symptoms and illnesses among its veterans. Yet, identifying a specific "Gulf War Syndrome" remains elusive. With new disease entities, causal associations are relatively easily established when the condition is serious, verifiable, and has excess disease rates in specific groups. In common conditions, many excess cases are required to establish association with a specific exposure. Establishing causality in syndromes with variable symptoms is difficult because specific diagnostic algorithms must be established before causal factors can be properly investigated. Searching for an environmental cause is futile in the absence of an operational disease case definition. Common subjective symptoms (without objective physical or laboratory findings) account for over one-half of all medical outpatient visits, yet these symptoms lack an identified physical cause at least one-third of the time. Our medical care system has difficulty dealing with disorders where there is no identified anatomic abnormality or documented metabolic/physiological dysfunction.

Causality↗
PubMed2002

Are Gulf War veterans experiencing illness due to exposure to smoke from Kuwaiti oil well fires? Examination of Department of Defense hospitalization data.

There has been much concern among the public and veterans that specific environmental exposures incurred during the Gulf War were the cause of subsequent illness among Gulf War veterans. In this historical cohort study, the authors compared the postwar morbidity of US military personnel exposed to smoke from the 1991 Kuwaiti oil well fires with that of unexposed personnel. Complete exposure and demographic data were available for 405,142 active-duty Gulf War veterans who did not remain in the region after the war. The authors used data from all Department of Defense hospitals for the period August 1, 1991-July 31, 1999 to estimate rates of hospitalization due to any cause, hospitalization due to a diagnosis in one of 15 major categories, and hospitalization due to one of nine diagnoses likely to be manifestations of smoke exposure. Exposures to particulate matter from oil-well-fire smoke were based on the integration of meteorologic data, diffusion modeling, and troop location data. The authors constructed seven exposure groups combining duration and amount of exposure. In Cox modeling, three of the 25 models showed an increased adjusted risk of hospitalization. However, there was no evidence of a dose-response relation. Despite some limitations, these data do not support the hypothesis that Gulf War veterans have an increased risk of postwar morbidity from exposure to Kuwaiti oil-well-fire smoke.

Adolescent↗
PubMed2002

Foodborne illness: new developments concerning an old problem.

Foodborne illnesses continue to cause substantial morbidity and mortality in the United States, primarily as gastroenteritis but occasionally as other syndromes as well. Most of these illnesses are caused by a variety of widely known infectious agents, principally viruses, and are probably the result of common mistakes in food handling in the home or in restaurants. The epidemiology of foodborne illness is evolving. Major changes in food production, distribution, and consumption have created opportunities for new pathogens to emerge and for old ones to reemerge, and the potential for widespread outbreaks is increasing. Antibiotic resistance in bacterial pathogens resulting from the widespread use of antimicrobial agents in animal husbandry is also an important concern. Clinicians must be aware of the changing epidemiology of foodborne illness to recognize and manage these conditions in the clinical setting. In addition, clinicians are critical in the reporting of recognized or suspected foodborne illness, so that public health authorities are able to investigate, understand, and ultimately better control them. A number of new techniques have been employed, and others under development will improve our ability to recognize and cope with foodborne diseases.

Bacterial Infections↗
PubMed2002

Ten years and 100,000 participants later: occupational and other factors influencing participation in US Gulf War health registries.

For more than a decade after the Gulf War, there has been concern that wartime exposures have resulted in significant morbidity among Gulf War veterans. After the end of the war, the Department of Veterans Affairs (VA) and the Department of Defense (DoD) initiated health registries to provide systematic clinical evaluations of Gulf War veterans who chose to participate. By September 1999, there were 32,876 participants in the DoD Comprehensive Clinical Evaluation Program and 70,385 participants in the VA Gulf War Registry Health Examination Program. We identified demographic and military service factors, as well as potential war-related exposures associated with subsequent registry participation after 10 years of observation. Veterans potentially exposed to oil well fire smoke, those near Khamisiyah, Reserve and National Guard, Army veterans, and veterans in the theater of operations during intense combat periods were most likely to elect to participate in a registry. These findings support the hypothesis that certain occupational factors and wartime exposures may influence subsequent health care-seeking behavior.

Adult↗
PubMed2002

The millennium Cohort Study: a 21-year prospective cohort study of 140,000 military personnel.

Does military service, in particular operational deployment, result in a higher risk of chronic illness among military personnel and veterans? The Millennium Cohort Study, the largest Department of Defense prospective cohort study ever conducted, will attempt to answer this question. The probability-based sample of 140,000 military personnel will be surveyed every 3 years during a 21-year period. The first questionnaire, scheduled for release in summer 2001, will be sent to 30,000 veterans who have been deployed to southwest Asia, Bosnia, or Kosovo since August 1997 and 70,000 veterans who have not been deployed to these conflict areas. Twenty thousand new participants will be added to the group in each of the years 2004 and 2007 to complete the study population of 140,000. The participants will have the option of completing the study questionnaire either on the paper copy received in the mail or through the World Wide Web-based version, which is available at www.MillenniumCohort.org. This will be one of the first prospective studies ever to offer such an option. The initial survey instrument will collect data regarding demographic characteristics, self-reported medical conditions and symptoms, and health-related behaviors. Validated instruments will be incorporated to capture self-assessed physical and mental functional status (Short Form for Veterans), psychosocial assessment (Patient Health Questionnaire), and post-traumatic stress disorder (Patient Checklist-17). Information obtained from the survey responses will be linked with other military databases, including data on deployment, occupation, vaccinations, health care utilization, and disability. In addition to revealing changes in veterans' health status over time, the Millennium Cohort Study will serve as a data repository, providing a solid foundation upon which additional epidemiological studies may be constructed.

Chronic Disease↗