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Vietnam-Era Twin Registry - In Progress & Recent Research Studies

The VET Registry is a resource for genetic epidemiological studies of mental and physical health conditions. The Registry provides a centrally managed resource and operates by collaborating with VA and non-VA investigators interested in questions related to Veteran health. These investigators, to whom we refer as Registry Investigators, have collected a wealth of health-related information on Registry twins. Since its formation, VET Registry members have participated in research studies across the country. Data has been collected via several waves of mail surveys, telephone interviews, in-person data collections, laboratory testing, and secondary data analysis studies. All collected data are returned to the VET Registry data and bio repositories. Visit the History & Formation page to learn about the origin of the VET Registry and the Publications page to view publications that have been produced from studies using the VET Registry.

Listed below are in progress or recently completed VET Registry studies. 

Vietnam-Era Twin Study of Aging (VETSA)

The Vietnam-Era Twin Study of Aging (VETSA) is a set of longitudinal, observational, epidemiologic investigations that examine genetic and environmental influences on cognitive and brain aging starting in midlife. The investigations have 2 main goals. The first goal is to understand the factors accounting for the great diversity of cognitive and brain trajectories in the twin members. The second goal is to advance the early identification of risk factors for mild cognitive impairment (MCI) and dementia. Because the pathological processes underlying dementia can begin decades before onset, early identification is one key to developing effective interventions. Recruitment for wave 4 of VETSA is anticipated to start Winter 2020; in most cases, members will be contacted about 5 to 6 years after they participated in VETSA wave 3.

Principal Investigators at University of California, San Diego (UCSD): Bill Kremen, PhD and Carol Franz, PhD
Principal Investigator at Boston University (BU): Michael Lyons, PhD

Study webpages:

A Twin Study of Chronic Back Pain and Associated Disability in Veterans

This is an observational study that examines the relationship between post-traumatic stress disorder (PTSD) symptoms, and chronic back pain and back pain-related physical functioning limitations. This study has 2 parts. Project #1 uses data from all 7568 Veterans who participated in CSP #569: Veteran Health Study (also known as A Twin Study of the Course and Consequences of PTSD in Vietnam Era Veterans), to examine cross-sectional associations between PTSD and self-reported back pain. Project #2 is a prospective, case-control study nested within the cohort from Project #1 that examines longitudinal associations between PTSD symptoms and incident back pain. Data is collected from participants for Project #2 via a mail survey.

Principal Investigator: Pradeep Suri, MD

Post-Traumatic Stress Disorder (PTSD) and Ischemic Heart Disease Progression: A Longitudinal Twin Study (ETSF)

A possible link between Posttraumatic Stress Disorder (PTSD) and Ischemic Heart Disease (IHD) has been suggested, but evidence for a causal connection is limited due to shortage of prospective studies using objective measures of IHD. A biological hallmark of PTSD is enhanced sympathetic nervous system (SNS) activity with stress, especially in response to trauma-reminiscent stimuli. This study’s overarching hypothesis is that repeated SNS activation with trauma reminders in PTSD leads to microvascular dysfunction, endothelial injury and immune activation which, in turn, increase the risk of myocardial ischemia and acute coronary syndromes.

Using a prospective twin design with objective measures of IHD, VETR14C05 Investigators will confirm a link between PTSD and IHD and test the new paradigm that immune and vascular reactivity during trauma reminders is a fundamental mechanism for the increased cardiovascular risk associated with PTSD. Such discovery will have substantial implications in our understanding of the long-term cardiovascular consequences of PTSD.

Principal Investigator: Viola Vaccarino, MD, PhD

CSP #569: Veteran Health Study

The goal of this study, also known as A Twin Study of the Course and Consequence of Post-Traumatic Stress Disorder in Vietnam Era Veterans, is to better understand the physical and mental health of Veterans as they grow older. This two phase data collection recruited from all twin members of the VET Registry, and included a 21-page mail survey (first phase) and a semi-structured psychiatric telephone interview and collection of information on the diagnoses of PTSD, depression, anxiety, and substance abuse (second phase). This study will help researchers understand how aging affects general health, disability, diabetes, PTSD, depression, and other issues. This information will assist VA in designing programs for prevention and treatment of the health problems of aging Veterans.

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

Family Studies of Health and Behavior

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 smoking, drinking, drug use, and depression. In one study, twins are being followed throughout their adult years to determine how their drinking habits change as they age. Another study focuses 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.

At Washington University, 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 alcohols, tobacco, and drugs.

Principal Investigators: Drs. Theodore Jacob (Palo Alto VA) and Kathleen Bucholz (Washington University)
Funding Agency: NIH-NIAA (VETR Study ID#: VETR1104) and VA Merit Review and NIH-NIAAA (VETR Study ID#: VETR0105) for Palo Alto VA studies; NIH-NIDA (VETR Study ID#: VETR0505) for Washington University studies

Biological Markers for Post-traumatic Stress Disorder (T3)

This study is using functional magnetic resonance imaging (fMRI) to examine the brain function in identical twin pairs, in which only one twin was exposed to combat during the Vietnam War. Twin pairs who may have already participated in the earlier two waves of this study were invited to participate. The goal of this study is to determine the origin of functional brain abnormalities in PTSD.

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

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 it relates to twins who were exposed to combat and are diagnosed with PTSD. Twin pairs who may have already participated in the earlier two waves of this study were invited to participate. The study includes an in-depth clinical evaluation involving interviews, questionnaires, memory tests, laboratory testing, and brain imaging.

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