Genetic Testing Can Change Behavior
Preliminary evidence suggests people respond more strongly to genetic risk.
People who find out they have high genetic risk for
cardiovascular disease are more likely to change their diet and exercise
patterns than are those who learn they have a high risk from family history,
according to preliminary research. The findings, from a personalized medicine study at the Coriell Institute
for Medical Research, a non-profit research institute based in Camden, NJ, suggest both a potential benefit of genetic
testing–inspiring patients to get healthy–and a misunderstanding of the power of genetics.
The research is part of a larger effort designed to help
answer two major questions surrounding genetic testing: how both patients and
doctors will react to the information and whether the information can actually improve
health outcomes. For example, someone who finds out he has a high genetic risk
of diabetes might adopt a fatalistic attitude and stop exercising, or he might
be motivated to start a new diet. The answers to these questions are becoming
increasingly important as the amount of genetic information available to both
patients and general consumers–via direct-to-consumer tests available via the
internet–has rapidly grown over the last couple of years.
“We need large
prospective studies to determine which aspects of genetic information change
behavior and improve outcomes,” said Michael Christman, the institute’s
president and chief executive officer, at a conference on consumer genetics
last week in Boston. “Genome information won’t be adopted in routine medicine
until its shown it does something.”
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Volunteers for the Coriell study, launched in 2007, provide information
on their family history, medical history, and demographics, as well as a saliva
sample for DNA testing. Each participant is screened for about 2 million different
genetic variations, as well as 2000 genetic markers in 225 genes linked to drug
metabolism. “This is where I think the sweet spot for personalized medicine
will be,” said Christman.
Researchers deliver the results through an educational web
portal and then survey patients and their physicians to assess how the testing
impacts behavior. Patients are given only the genetic information deemed
medically actionable, and they choose which results they want to share with
their doctors.
In addition to genetic risk, researchers calculate disease
risk from an individual’s family history, environmental factors, such as
smoking, and comorbid diseases, such as diabetes. All of this information is
displayed side-by-side when patients access their results for a particular
disease. “We find that’s important for both patients and doctors since people
tend to place undue emphasis on genetics,” said Christman.
Patients still seem to consider genetic information to be
special, however. Researchers surveyed patients to find out how they reacted to
discovering they carry one or two copies of a variation linked to higher risk
of heart disease. People with two copies
took it “very seriously, making big changes to diet and exercise,” says
Christman. That wasn’t true for those with only one copy, or for those whose
family history predicted just as high a risk as that conferred by two copies of
the risk gene. Researchers haven’t yet determined how genetic testing effects
long term health, which will require extensive follow-up.