Genetic Epidemiology of Coronary Heart Disease Risk in Women Twins

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00005239
Recruitment Status : Completed
First Posted : May 26, 2000
Last Update Posted : February 18, 2016
Information provided by:
National Heart, Lung, and Blood Institute (NHLBI)

Brief Summary:
To examine genetic and environmental influences on several recently identified coronary heart disease risk factors in identical and fraternal adult women twins. The risk factors included low density lipoprotein (LDL) subclass patterns, plasma apolipoprotein levels, body fat distribution, and serum insulin levels.

Condition or disease
Cardiovascular Diseases Coronary Disease Heart Diseases

Detailed Description:


In 1974, a twin registry was established from members of the Kaiser Permanente Medical Care Program's Northern California region. In all, 9,821 twin pairs were enrolled. In 1978-1979, 434 pairs of female twins were recruited from the registry for a clinical examination of coronary heart disease risk factors. The clinical examination included an extensive health questionnaire, measurements of plasma lipids and serum chemistries, analyses of genetic markers for determination of zygosity, measurement of expired air carbon monoxide and serum thiocyanate levels, and a complete physical examination. During the ten years since the first examination, several new or more specific coronary heart disease risk factors have been recognized, including low density lipoprotein and insulin levels, and the anatomic distribution of body fat.


All women who participated in the first examination were invited to participate in the second examination. Medical records and/or death certificates were obtained to document coronary heart disease events. Questionnaires were used to collect information on health history, nutrition, and physical activity. A clinical examination assessed blood pressure, a variety of anthropometric measures and cardiovascular fitness. Blood specimens were collected for clinical chemistry and lipid/lipoprotein profiles. To assess genetic influence, the heritability of each of the risk factors was estimated. Blood was frozen for future studies of polymorphic DNA markers. Using the monozygotic co-twin control method, the effects of environmental or behavioral factors on these risk factors were assessed after controlling for genetic factors that could explain their association. Two hypotheses were examined that could be uniquely addressed using twin data. First, the association of body fat distribution with other coronary heart disease risk factors was mediated by serum insulin levels. Secondly, cardiovascular fitness explained in part the association of physical activity with coronary heart disease risk factors such as HDL-cholesterol and insulin levels. Lipoprotein analyses were conducted at Donner Laboratory at Berkeley.

The study completion date listed in this record was obtained from the "End Date" entered in the Protocol Registration and Results System (PRS) record.

Study Type : Observational
Study Start Date : January 1989
Actual Study Completion Date : December 1991

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Ages Eligible for Study:   up to 100 Years   (Child, Adult, Older Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   No
No eligibility criteria

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To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00005239

Sponsors and Collaborators
National Heart, Lung, and Blood Institute (NHLBI)
OverallOfficial: Joseph Selby Kaiser Foundation Research Institute

Publications: Identifier: NCT00005239     History of Changes
Other Study ID Numbers: 1120
R01HL041830 ( U.S. NIH Grant/Contract )
First Posted: May 26, 2000    Key Record Dates
Last Update Posted: February 18, 2016
Last Verified: June 2004

Additional relevant MeSH terms:
Cardiovascular Diseases
Heart Diseases
Coronary Disease
Coronary Artery Disease
Myocardial Ischemia
Vascular Diseases
Arterial Occlusive Diseases