Selected Vietnam Era Registry Research Studies

For any questions regarding studies conducted at the Registry, please contact the VET Registry toll-free at 1-866-774-9647.

Select VET Registry Studies Currently Collecting Data 

The goal of the Veteran Health Study is to better understand the physical and mental health of Veterans as they grow older. In this study twins complete a pencil and paper questionnaire about their physical health and are interviewed by telephone about their mental health. The knowledge from this study will help researchers understand how aging affects general health, disability, diabetes, PTSD, depression, and other issues. This information will assist the VA in designing programs for prevention and treatment of the health problems of aging Veterans. (Note this study is also known as, “CSP #569: A Twin Study of the Course and Consequences of Post-traumatic Stress Disorder in Vietnam Era Veterans.”)

Funding Agency: VA Cooperative Studies Program (VETR Study ID#: VETR0705)
Principal Investigators: Jack Goldberg, PhD (University of Washington) and Kathy Magruder, PhD (Ralph H. Johnson VA Medical Center)

VETSA 2: A Longitudinal Study of Cognitive Aging

The goal of VETSA is to follow twins throughout their lives, contacting them every 5 years to learn about genetic (nature) and environmental (nurture) factors that influence the aging process. The VETSA magnetic resonance imaging (MRI) studies are linked to the main VETSA project and are studying the brain and how it changes as Veterans age. Through these studies, researchers hope to learn about the influence genes have on the aging brain. Their studies include over 1,200 twins and follow-up research on these twins is now underway.

Funding Agency: NIH-NIA (VETR Study ID#s: VETR0106 and VETR1008)
Principal Investigators: William Kremen, PhD, (University of California, San Diego) and Michael Lyons, PhD (Boston University)

Alcoholism Course thought Midlife: A Twin Family Study and Offspring of Twins: G, E and GxE Risk for Alcoholism

Studies at the VA in Palo Alto, CA focus on the mental and physical health of Veterans and their families with an interest in determining how genes and experiences affect whether people smoke, drink, use drugs, and have depression. In one study, twins are being followed throughout their adult years to determine how their drinking habits change as they age. In another study, the focus is on adult children of twins to determine similarities and differences in health patterns across the generations. It is hoped these studies will help clinicians design prevention and treatment programs.

Funding Agency: NIH-NIAA (VETR Study ID#: VETR1104) and VA Merit Review and NIH-NIAAA (VETR Study ID#: VETR0105)
Principal Investigator: Theodore Jacob, PhD (VA Palo Alto Health Care System)

GE: Offspring of Twins with Substance Use Disorder

At Washington University in St. Louis, MO, the Transition to Adulthood Project (TAP) began collecting data from Registry twin fathers and their families in 2002 and is currently conducting follow-up interviews with the adult children of twins. The TAP team is measuring young adult milestones, like marriage and parenthood, completion of education, occupation and job satisfaction; the team will examine how these milestones relate to health, especially in the areas of mood and the use of alcohol, tobacco and drugs.

Funding Agency: NIH-NIDA (VETR Study ID#: VETR0505)
Principal Investigator: Kathryn Bucholz, PhD (Washington University)

Mechanisms Linking Depression to Cardiovascular Risk (Twins Heart Study 2)

The goal of this research is to measure the influence of mental health on heart disease. The SAVE IT study involves participants traveling to Atlanta to undergo testing for early symptoms of heart disease.

Funding Agency: NIH-NHLBI (VETR Study ID#: VETR0209)
Principal Investigator: Viola Vaccarino, MD, PhD (Emory University)

Post-traumatic Stress Disorder and Cardiovascular Disease

The objective of the THS-2 study is to better describe the role of emotional depression on heart disease. Eighty pairs of twins who had already participated in an earlier phase of this study, have been invited to participate. This new study will look at how heart disease progresses and the relationship between the depression and heart disease.

Funding Agency: NIH-NHLBI (VETR Study ID#: VETR1203)
Principal Investigator: Viola Vaccarino, MD, PhD (Emory University)

Biological Markers for Post-traumatic Stress Disorder (T3)

This study is using functional magnetic resonance imaging (fMRI) to compare the brain function in identical twin pairs, where only one twin was exposed to combat during the Vietnam War. The goal of this study is to determine if specific brain regions function differently in combat Veterans with PTSD compared with their identical twins who were exposed to combat and do not have PTSD.

Funding Agency: NIH-NIMH (VETR Study ID#: VETR0207)
Principal Investigator: Lisa Shin, PhD (Massachusetts General Hospital)

Memory and the Hippocampus in Vietnam-era Twins with PTSD (Time 3)

The purpose of this study is to look at an area of the brain involved in learning and memory (called the hippocampus) over time and see how that relates to twins who were exposed to combat and have a diagnosis of PTSD. The study includes an in-depth clinical evaluation involving interviews, paper and pencil questionnaires, tests of memory, laboratory testing, magnetic resonance imaging (MRI), and positron emission tomography (PET) imaging of the brain.

Funding Agency: VA Merit Review (VETR Study ID#: VETR0307)
Principal Investigator: J. Douglas Bremner, MD, PhD (Emory University)

Summary of Past Full Registry Data Collection Projects

The twin identification process from military records took approximately 3 years from 1983-1986. The research initiatives outlined below have attempted to collect information from all twins in the VET Registry. We present a snapshot of data available from the:

1. 1983-1986 Registry Construction ~ Military Records 
2. 1987 Survey of Health 
3. 1991 National Heart Lung and Blood Institute Survey
4. 1993 Harvard Twin Study of Substance Abuse
5. 1999 Male Health Survey

Registry Construction ~ Military Records

Data were abstracted from the veteran military records as part of the construction of the VET Registry (Eisen et al., 1987). The limited set of variables included: date of birth, date of enlistment into the military, rank at enlistment, education at enlistment, height, and weight at enlistment, blood pressure, medals received, and date of discharge. 
VETR Study ID#: CSP #256-VETR

1987 Survey of Health

The 1987 Survey of Health represented the first direct contact with the twin pairs. A 24 page survey was developed that assessed a broad range of health outcomes. The survey was designed to serve several purposes, the first being most critical: 1) define the zygosity so that monozygotic and dizygotic twins could be reliability distinguished (Eisen et al., 1989) and 2) assess the most likely health-related long-term consequences of service in Vietnam (Goldberg et al., 1990; Eisen et al., 1991). Data collection was by mail with telephone follow-up for non-responders. Data items include: zygosity, combat exposure, symptoms of post-traumatic stress disorder, physical health problems, cigarette smoking and alcohol consumption, marriage and divorce history, and number of children. In total 10,979 individuals responded to the mail and telephone survey for a 74% response rate; the pair-wise response rate for twins was 64% representing ~4,774 pairs where both responded. 
VETR Study ID#: CSP #256-SOH

1990 National Heart Lung and Blood Institute Survey

In 1990, the National Heart Lung and Blood Institute contracted with the VA under an interagency agreement to conduct a mailed and telephone survey of the VET Registry twins to obtain data on disorders of interest to the Institute. A 24 page survey was developed in collaboration with staff at NHLBI. The data items include: cardiovascular risk factors, self-reported heart, lung and blood disorders, sleep problems, diet and exercise (Fabsitz et al., 1997). In total 8,870 individuals responded to the mail and telephone survey; and this resulted in 3,698 pairs where both responded. 
VETR Study ID#: CSP #997

1993 Harvard Twin Study of Substance Abuse

This study was initiated in 1993 to study the genetics of substance abuse. All data were collected by telephone interview using the Diagnostic Interview Schedule (Robins, et al., 1981) to assess a wide variety of psychiatric disorders according to the American Psychiatric.

Association, Diagnostic and Statistical Manual III-R (REF). This interview included 15 psychiatric diagnoses, such as: alcohol and drug abuse (Tsuang et al., 1996), post-traumatic stress disorder, depression, and anti-social personality. In total 8,169 individuals responded to the telephone interview resulting in responses from 3,372 complete twin pairs. 
VETR Study ID#: CSP #992

1999 Male Health Survey

This study was initiated in 1999 with internal support from the VA. All data were collected by a two page mail survey as part of the VET Registry newsletter. The brief survey focused on issues related to male health, such as symptoms of urinary tract problems and erectile dysfunction. In total 5,349 individuals responded to the survey which resulted in 1,615 complete pairs.
VETR Study ID#: CSP #993-T