WEDNESDAY, Jan. 12, 2011 (HealthDay News) -- People who have direct-to-consumer genetic testing don't experience any short-term increase in anxiety after receiving the results, whether they are positive or negative, researchers report.
Nor do they make any lifestyle changes or get screening tests that might modify that risk, despite professing the intention to do so, according to a study in the Jan. 13 issue of the New England Journal of Medicine.
"This has been a contentious area," said senior study author Dr. Eric Topol, director of the Scripps Translational Science Institute in La Jolla, Calif. "There have been proclamations that this would induce a tremendous amount of fear and trauma for people and speculation as to whether it would help at all, and there were some things [in this study] that were encouraging."
This is the first study to investigate the impact of such genome-wide scans on people, he added.
Direct-to-consumer genetic (DTC) testing, in which consumers can have their genome checked for everything from caffeine metabolism to Alzheimer's risk, is a relatively new phenomenon, and experts are still sorting out the pros and cons of the practice.
Last year, Pathway Genomics announced that it would start selling tests (in general, the test can cost from $400 to $2,000) at Walgreen's stores, which are ubiquitous in the United States. (Walgreen's reversed its decision, however, after the U.S. Food and Drug Administration raised questions about the supplier.)
Even if patients are not disturbed by the results of direct-to-consumer genome-wide profiling, experts are worried that the results may not be valid. Dr. Bruce R. Korf, president of the American College of Genetics, is concerned about is whether the data "given to patients was accurate to patients. This [study] was not intended to assess whether the tests had clinical validity or were clinically useful."
And there has been considerable debate on that point. An undercover investigation of 15 DTC genetic testing services by the U.S. Government Accountability Office found "'egregious examples of deceptive marketing, in addition to poor or nonexistent advice from supposed consultation experts," according to the medical journal The Lancet.
The current study examined about 2,000 participants who were recruited to take a genome-wide test known as Navigenics Health Compass, described by the study authors as "a commercially available [genetics] test of uncertain validity and utility," at a discounted rate. In a baseline questionnaire completed by the participants, there were no differences in anxiety or in exercise levels or in fat intake before and five-to-six months after the test was taken.
More than 90 percent of participants, who tended to be well-educated, had no test-related distress.
And although participants expressed the desire to get relevant screening tests, most did not.
The scan tested for more than 20 health conditions including macular degeneration, heart attack, colon cancer and psoriasis. The risk for all could be modified.
"There's no evidence of improving lifestyle, which is sobering but nothing else has improved lifestyle, so maybe we shouldn't have been so surprised," Topol said.
"We saw a nice relationship between risk and the desire to get health screening but a lot of patients had not done the screening. But they had registered awareness," he added.
Navigenics Health Compass did not respond to a request from HealthDay for comment on the findings.
The study, which is funded by the National Institutes of Health and Scripps Institute, will be ongoing for 20 years, leaving time for some of those results to change.
"At least we've got the groundwork laid that people are going to do OK getting that information. They're not going to be depressed or anxious," Topol said. "We can't expect it to be a way to get people to take better care of themselves."
He and the other researchers noted the study also had a number of limitations, including the lack of a control group, its lack of representation of the population in general, and a large percentage of people (44 percent) who failed to complete the study -- a fact that researchers noted could possibly indicate that some drop-outs were psychologically distressed by the genetic testing results.
Other experts also stressed that the findings do not absolve direct-to-consumer genetic testing kits of the possibility for harm.
The study did not address the possibility of "false reassurance," pointed out Korf, who is also chair of genetics at the University of Alabama at Birmingham.
"There is some concern that somebody is going to learn they're at somewhat reduced risk for, let's say type 2 diabetes, and decide because of that they don't need to watch their diet any more," he said. "The [test] may not give you the whole story and may not even be true for [that patient]."
"We've felt pretty strongly that, for the most part, this type of consumer genomic profiling is not ready for prime time, not because of anxiety but because tests have not been validated [so that] we know they are giving correct information," Korf added. "You have to know what you can and can't learn from this and what kinds of things you can do."
More information
The U.S. National Library of Medicine has more on genetic testing.
