12 Oct 2011

As direct-to-consumer genetic testing becomes increasingly popular, many in the public healthcare field have worried over how people will react to information about their genetic risk for diseases. Will the knowledge cause undue distress, or lead people to misunderstand their disease susceptibility? Perhaps not, a new paper suggests. In the October Mayo Clinic Proceedings, researchers led by Clayton Cowl at the Mayo Clinic in Rochester, Minnesota, report that in a selected population, disclosing genetic risks for a handful of diseases had but a mild and transient effect on people’s state of mind. One caveat is that this study only looked at diseases that might be pre-empted by lifestyle changes or early preventive screenings. It included no genetic tests linked to neurodegenerative diseases. Formal guidelines for sporadic Alzheimer’s disease genetic testing currently do not recommend genotyping for ApoE, which is by far the strongest genetic risk (see ARF related news story). In addition, the Mayo Clinic study did not examine whether people changed their behavior as a result of genetic information, a key question that awaits future studies.

First author Katherine James recruited 150 volunteers from among well-educated, insured patients scheduled to receive a comprehensive preventive healthcare visit at the Mayo Clinic. While not a random sample of the general public, this population probably represents the group most likely to purchase direct-to-consumer genetic tests, Cowl told ARF. Half the participants received genetic test results from Navigenics, Inc., a DNA testing company in Foster City, California. The panel comprised risk factors for 12 diseases ranging from cancers, diabetes, heart attacks, obesity, Graves' disease, and osteoarthritis. Participants viewed their results on the Internet, and brought the data to their healthcare appointment one week later to discuss with their doctor. To approximate a real-world direct-to-consumer experience, the researchers gave physicians no special instructions on how to handle the information. For most participants, their genetic report combined good news and bad news, showing a higher-than-average risk for some conditions but a lower-than-average risk for others. For example, a 9 percent lifetime risk of colon cancer (higher than the population average of 6 percent) might come with a 20 percent risk of diabetes (lower than the population average of 25 percent).

One week after the appointment, participants completed a survey indicating how likely they thought they were to get each of the specified diseases, and how worried they were about that. For five of the 12 diseases, the control and experimental groups varied in their risk perception, but in somewhat unpredictable ways. People who had received genetic information rated their risk higher than the control group did for four diseases, including some rare conditions, but their risk estimates for prostate cancer were lower. In general, people who had a higher-than-average genetic risk of getting a particular disease also reported the highest perceived risk, Cowl told ARF. In contrast, all participants reported similar levels of worry about getting each of the diseases. In a second survey given one year later, the responses of the two groups were statistically indistinguishable on all measures.

Despite the fleeting nature of altered risk perceptions, they might influence healthcare decisions people made at the time of their doctor’s visit, the authors suggested. They are currently assessing the physicians’ impressions to see if they found the genetic risk information a useful addition to their tool chest. “With this cohort of patients, who are fairly savvy medical consumers, I don’t think [the genetic information] caused any untoward side effects in the way they thought about their health. For most cases, it probably assisted the physician in pushing them toward a certain healthcare goal,” Cowl said.

Other scientists cautioned that the findings might not translate to the broader population. “We need more studies to show how a general population would be able to interpret these kinds of direct-to-consumer genetic results, and how they use the information to change their health behaviors and lifetime planning,” said Jill Goldman at Columbia University, New York City, a genetic counselor who focuses on neurodegenerative diseases.

“This is a well-designed addition to the literature,” said Robert Green at Brigham and Women’s Hospital, Boston. Green led the Risk Evaluation and Education for Alzheimer’s Disease (REVEAL) study, which examined the effects of telling people their ApoE genotype (see ARF related news story). REVEAL also found that the psychological effect of communicating genetic risk information was short-lived, disappearing within six months, Green said, adding that the big question remains unanswered: Does direct-to-consumer genetic testing have an overall positive, negative, or neutral effect on public health? Genetic information might motivate people to make healthy lifestyle changes, for example, but conversely, a low genetic risk for a disease might confer a false sense of reassurance and lull a person into slacking off on healthy habits. To address this question, in 2012 Green and colleagues will start to study people receiving a full slate of genetic information, including ApoE genotype, from two direct-to-consumer California companies, Pathway Genomics in San Diego and 23andMe in Mountain View. The researchers will study what motivated people to seek genetic testing, how they reacted, and what they did differently afterward, if anything.—Madolyn Bowman Rogers

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References

News Citations

1. Early ApoE4 Memory Effects, But Do You Really Want to Know? 17 Jul 2009

Other Citations

1. ARF related news story

Further Reading

News

1. Formal Guidelines Issued for Alzheimer’s Genetic Testing 15 Jul 2011
2. Early ApoE4 Memory Effects, But Do You Really Want to Know? 17 Jul 2009