Why Twin Studies Are Important in Science

SRI's hope is that the study of health behaviors in twins will help to identify the extent to which health is influenced by genetics or the environment. Identification of the genetic component to health will, in turn, help SRI and others to target more accurately efforts to improve public health. SRI's Center for Health Sciences formed the Northern California Twin Registry.

"Twins - with their similar genetic make-up - represent an ideal way to study various health and behavior issues and determine more exactly what influence genetic factors play and what influence environmental factors may play," explains Gary Swan, Director, SRI's Center for Health Sciences. "Twin studies have provided scientific insights into such issues as diabetes, heart disease, obesity, as well as alcohol and tobacco use. By identifying a genetic component to these and other health issues, we can target early prevention and treatment efforts."

SRI International works with an existing registry of twins that was developed more than 20 years ago. For the past 15 years, SRI's Center for Health Sciences has utilized the registry by conducting and coordinating a variety of health studies. That original twin registry focused on male veterans of World War II, many of whom are in their late 60s and 70s. Results from this study have been published in the New England Journal of Medicine, the Journal of the American Medical Association (JAMA), and other noted health and science publications.

By developing the Northern California Twin Registry, SRI International hopes to respond to the need for better representation of ethnic and gender diversity in health research involving twins and thereby develop a valuable science resource for studying human behavior. Northern California, with its large and diverse population base, provides ideal demographics for the Registry. By studying twins, insights related to behavior and health -- including smoking, drinking, over eating, exercise, obesity and other behaviors -- can be gathered and analyzed.

In the twin studies conducted thus far, SRI has identified genetic influences on a variety of health-related issues. Key findings include:

• Obesity over the life span is determined, in part, by different genetic factors as people get older
• Tobacco smoking is determined partly by genetic factors, some of which may also underlie alcohol use
• Change in memory function in aging adults is influenced partly by genetic factors; in identical twins who were different on memory change, blood pressure appeared as a significant determinant of this change.

Contact Us
Inquiries or comments on the Registry are welcome and can be directed to:

Center for Health Sciences
SRI International
333 Ravenswood Avenue
Menlo Park, CA 94025
SRITWIN@sri.com

Phone: 1-800-SRI-TWIN (1-800-774-8946)
Fax: 650-859-5099