Research Studies
The twin identification process from military records took approximately 3 years from 1983-1986. Since that time there have been four research initiatives that have attempted to collect information from all twins on the VET Registry. We present a snapshot of data available from the:
a. 1983-1986 Registry military record,
b. 1987 Survey of Health,
c. 1991 National Heart Lung and Blood Institute Survey,
d. 1993 Harvard Twin Study of Substance Abuse and
e. 1999 Male Health Survey.
| Summary of VET Registry Data Collection Projects |
| Study Name |
Type of Study |
Recruitment Period |
Number Participated |
Complete Pairs |
| Registry Construction |
| Military Records |
Record Abstracts |
1983-1986 |
14,750 |
7,375 |
| Surveys of the Full Registry |
| Survey of Health |
Mail/ Telephone Follow-up |
1987 |
10,979 |
4,774 |
| NHLBI VET Study of Cardiovascular Disease |
Mail/ Telephone Follow-up |
1990 |
8,169 |
3,698 |
| Harvard Twin Study of Drug Abuse and Dependence |
Telephone |
1991-1993 |
10,979 |
3,698 |
| Male Health Survey |
Mail |
1999 |
5,349 |
1,615 |
| Studies of Selected Twins |
| Impulsivity and Aggression |
Mail/ Telephone Follow-up |
1992 |
796 |
314 |
| Consequences Of Drug Abuse |
In-Person |
1995-1996 |
254 |
127 |
| Alcohol and Health Services Utilization |
Telephone |
1995 |
2,936 |
|
| Biologic Markers for PTSD |
In-person
Telephone |
1995-1998
1995-1996 |
322
2,003 |
161
322 |
| Alcohol Vulnerability |
In-person |
1997-1999 |
760 |
380 |
| PTSD Sleep Study |
In-person
Telephone |
Ongoing |
11/22
207/248 |
9
248 |
| Twin-Family Study of Health Behaviors |
Telephone and Mail |
Ongoing |
533 |
214 |
| PTSD MRI Study 1 |
In-person |
Ongoing |
48 |
45 |
| PTSD MRI Study 2 |
In-person |
Ongoing |
52 |
|
| New Studies of Selected Twins |
| Pathological Gambling |
Telephone |
Newly Funded |
2510* |
1,255* |
| Spirituality and PTSD |
Mail |
Newly Funded |
510* |
255* |
| Cardiovascular Disease and Depression |
In-person |
Newly Funded |
320* |
160* |
| Twins as Parents |
Telephone and Mail |
Newly Funded |
1060* |
530* |
Military Record Information
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.
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 pairwise response rate
for twins was 64% representing ~4,774 pairs where
both responded.
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.
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.
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.
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