Think After You Spit: Personal Genomic Tests May Offer a Teachable Moment

July 26th, 2012 2:35 pm ET - Muin J Khoury, Director, Office of Public Health Genomics, Centers for Disease Control and Prevention

Katherine Kolor, Office of Public Health Genomics, Centers for Disease Control and Prevention

Patient is showing physician her DTC genetic test results

Personal genomic tests are now widely available and sold directly to consumers, but population-based data are limited on awareness, use and impact of these tests. In collaboration with 4 state public health genomics programs, we have recently reported on consumer awareness and use of personal genomic tests using the 2009 Behavioral Risk Factor Surveillance System

. Awareness of personal genomic tests ranged from 15.8% in Michigan to 29.1% in Oregon. Factors associated with increased awareness include higher education, higher income, and increasing age (up to age 75 years). Awareness is greater in this study compared with a similar survey conducted in 2006. Although less than 1% of respondents had used these tests, we estimated thatbetween 200 thousand and over 1 million people

have undertaken these tests in the US, with about one-half of them sharing the results with a health-care provider. These data indicate a potentially “teachable moment” for consumers and health care providers to engage in a dialogue on improving health and preventing disease using these tests as a starting point for discussion.

Our position on personal genomic tests for improving one’s health was expressed in 2011 in a post entitled “think before you spit” and remains largely unchanged. We are still concerned about the limitations of these tests in risk assessment and disease prevention for common diseases, advocate for a better scientific foundation

for their use, and promote an informed decision making by consumers, providers and policy makers.

Since 2011, there continues to be an improvement in technological developments and a proliferation of test offerings directly to the public. In addition, there have been several studies

conducted on the impact of personal genomic tests on behavior of participants. Although these studies have shown that consumers report concerns related to privacy, worry about receiving the results, and reliability of test results, what we know so far is that, by and large, risk information offered by personal genomic tests, on the short run, is “neither as harmful as feared by critics nor as empowering as promised by providers

”. A recent systematic review

concluded that most consumers desire guidance by a health professional when considering personal genomic tests.

So what can people who undertake personal genomic testing to improve health and prevent disease do with this information? First, we encourage consumers to have a healthy dose of skepticism about the interpretation of the findings, their probabilistic nature, and their utility for improving their health. With the exception of a few rare genetic variants, the interpretation of the test findings, especially the numbers reflecting individual risk of developing diseases should be viewed cautiously. The meaning of “above average” and “below average” life time risks of disease is still based on incomplete scientific data

and needs to be interpreted in the context of how common the disease is and the person’s other risk factors

. In other words, a “below average” risk of heart disease will still mean a high risk of heart disease since heart disease is very common, whereas an “above average” risk of multiple sclerosis will still mean a low risk since the disease is much less common than heart disease.

Second, we encourage consumers to discuss and share the results of tests with their health care providers, especially in the case of reported mutations with high risk for certain genetic conditions or carrier state for these conditions. Most findings do not merit follow up action by providers in terms of ordering more tests or altering treatments and other interventions.The clinical “actionability”

of variation in the genome is still being debated and will be unknown for quite some time. There is currently very little information or guidance from professional groups or independent panels on the benefits and harms of acting on findings from personal genomic testing such as earlier disease screening, prescription of medications, or other interventions. In fact, the few independent evidence-based reviews of certain genetic variants included in personal genomic tests have discouraged their use

in clinical practice.

Third, regardless of what is in the genetic test result, we encourage consumers to seek, collect and validate as much as possible their family health history. The interpretation of genetic risks, especially for rare genetic conditions, could be highly dependent on the presence or absence of family history of certain diseases. There are several available free tools to download for use in family history collection, notably the US Surgeon General my Family Health Portrait

. Family history has value in and of itself, in pointing to general health concerns, independent of the genetic risk factor information derived from available tests.

Fourth, there are general disease prevention and health promotion messages that are important, regardless of one’s genetic risk profile, including smoking cessation, physical activity, diet, vaccinations, injury prevention, and infectious disease control. For a complete list of disease prevention and health promotion recommendations, we refer consumers toCDC’s website for updated health-related messages.

Finally, personal genomic tests can offer a unique process for consumers to use a “genomics lens” to learn about determinants of health and disease and to enhance both family and patient-provider interactions. By educating ourselves about the evolving knowledge ofgenomic and environmental determinants of common diseases and the current limitations of genomics, we can take charge of our own health, broaden our knowledge base, and continuously seek reliable and credible sources of health related information in the midst of tremendous background noise, unsubstantiated claims and rapidly changing science.