|April 14, 2011|
Direct-to-consumer genetic testing satisfies the curious, but at what cost?
Recent surveys provide a glimpse into the psychological, behavioral and clinical impact of test results
National DNA Day, which is tomorrow, represents an ideal occasion to recognize the growing interest in how genes influence our health. We credit, or blame them for the bodies we have, and we are increasingly told that they hold the secret to living longer and smarter.
A “DNA Day sale” offered by genome-profiling company 23andMe exclaims, “Start filling in the gaps with your DNA.”
The FDA is currently considering whether to regulate the claims and operations of direct-to-consumer (DTC) genetic testing companies, given concerns about the reliability of results, lack of industry standards, and the question of whether genetic testing companies should be required to make sure a clinician is available to help customers interpret the results.
Several major studies have been conducted recently on how DTC test results affect the behavior and actions of those who have their genomes decoded. One survey, funded by the National Institutes of Health, polled 1,048 customers of 23andMe, Navigenics and deCODEme between January and May 2010. That survey was led by the Genetics and Public Policy Center, a part of the Johns Hopkins Berman Institute of Bioethics.
In another study, researchers surveyed 3,639 subjects from technology and health companies who bought a Navigenics service called “Health Compass.” Just over 2,000 of the individuals completed follow-up questions about anxiety or changes they made to their diet or exercise routines because of their test results. This study, featured in the Feb. 10 issue of the New England Journal of Medicine, was also funded by the National Institutes of Health, as well as Scripps Health.
In essence, both surveys reported that participants experienced minimal distress about their test results and did not alter their exercise routines much in response to them. A significant percentage did discuss their results with a health professional. So, have critics of DTC tests been fretting over nothing?
Not necessarily, says Prof. Gail Geller, who focuses on the ethical and psychosocial implications of genetic technologies. Although these studies give researchers, regulators and the rest of us a glimpse into how DTC tests affect some individuals, Geller says the surveys do not necessarily reflect how people in general would react to results that indicate they may be genetically predisposed to certain diseases or conditions.
In addition, Geller points out several issues in the larger study that make its findings seem even less conclusive. First, the survey in NEJM conflated two different kinds of genetic tests: those that look for inherited mutations that have a high likelihood of resulting in disease—such as breast or colorectal cancer—and those that look for common gene variants that have a low likelihood of causing illness.
“Direct-to-consumer genetic tests focus on the latter, which, by their very nature, are less likely to cause anxiety because their clinical significance is very low,” Geller said.
She also noted that there are several types of harm—beyond anxiety—that people can experience because of genetic testing. The participants in these studies may not have worried much about test results that indicate an increased risk of disease. But Geller said they may have developed a false sense of reassurance from results that indicate a decreased risk of disease.
“We would not want women with lower than average breast cancer risk to avoid having mammograms, or people with a lower than average lung cancer risk to conclude that smoking is safe,” Geller said. “This would be a greater harm than anxiety.”
In the study conducted by the Genetics and Public Policy Center (GPPC), more than a quarter of those surveyed discussed their results with a health professional, and 20 percent shared them with their primary-care provider. And among the 16 percent of respondents who altered their medication or supplement regimens after their test, just over half said they shared their results with a healthcare provider.
Meanwhile, the NEJM article stated that people who underwent personal DNA analysis did not significantly increase their use of medical screenings afterward—although there was an increase in intention to screen among those indicated to be at higher genetic risk. However, Geller points out, there is a common bias in survey research called “social desirability,” in which respondents give answers that they think the researchers want to hear.
But perhaps most importantly, the samples in both studies were not representative of the general population. An article in Nature on the NEJM study stated that participants belonged to a nonprofit health network or worked at nearby technology companies. So these people were more likely to be active in their own health care, or in the case of the tech workers, be well-educated—and therefore less representative of the public at large.
Of greater concern, Geller noted, is that those who choose to have their DNA analyzed are a self-select group of active information “seekers.” In other words, they are more likely to feel anxious if they do not receive information that bears on their health than if they do receive such information.
By contrast, Geller continued, those who decline participation—or drop out of the study before the results are disclosed—may be more prone to anxiety if they receive information that indicates they have a slightly elevated risk of disease than if they avoid that information.
“This study had significant non-participation and drop-out rates,” Geller said. “Therefore, the low anxiety levels among participants in this study may reflect this selection bias.”
At an FDA hearing on March 8, results from the GPPC survey were presented by the center’s director of research and statistics, Dave Kaufman. Testifying before an advisory panel that is assessing whether DTC genetic tests should be allowed to remain widely available, Kaufman said that, of the 1,048 participants polled, 87 percent were white, two-thirds reported annual household incomes over $85,000, and more than half had some form of post-graduate education.
“The relatively wealthy and well-educated make-up of early adopters of DTC genetic testing must be kept in mind when interpreting research findings about comprehension of the results and follow-up behaviors,” Kaufman told the panel.
He ended by saying that longer, more detailed studies will be needed to measure whether DTC genetic tests truly have health benefits, or result in harm. The authors of the study in NEJM concluded on a similar note: “Potential effects of this type of genetic testing on the public at large are not known.”
(Note: A detailed, first-person account of someone with a family history of certain diseases, and took a DTC test that her brother bought as a gift from 23andMe, is at http://www.fairwarning.org.)