Expert Commentary

Direct-to-consumer genetic testing: Research review

What happens when you take genetic tests out of the doctor's office? Research highlights the effects of direct-to-consumer testing services.


While clinical genetic testing is a common medical practice, in the past decade, the introduction of direct-to-consumer (DTC) genetic testing has moved the practice out of the doctor’s office and into the home. DTC genetic testing companies such as 23andMe provide genotyping services that reveal the genetic basis of family heritage, physical traits and health conditions.

This last component of DTC genetic testing – providing information on health risks — proved controversial from the start. In July 2009, the Food and Drug Administration (FDA) began talks with 23andMe to discuss regulating the services they provide, though these conversations did not lead to any changes. However, a televised ad campaign run by 23andMe in August 2013 that focused on the benefits of learning about health information through DTC testing prompted the FDA to shutter this arm of 23andMe’s operations. The FDA argued that if 23andMe was to market their services as “medical devices,” the products must be FDA approved.

On November 22, 2013, the FDA issued a warning letter to 23andMe, preventing the release of health information in their genetic test results. The letter said that 23andMe had not scientifically proven that its tests served the aims they were advertising, namely that they provide useful information for improving personal health. Further, the FDA worried consumers might be misled by potentially incorrect test results.

But in April 2017, the FDA approved marketing of 23andMe for a number of health conditions, including Parkinson’s disease, late-onset Alzheimer’s disease and Celiac disease. “Authorization of the 23andMe Genetic Health Risk (GHR) tests was supported by data from peer-reviewed, scientific literature that demonstrated a link between specific genetic variants and each of the 10 health conditions,” the FDA wrote in a news release.

Most recently, in March 2018 the FDA authorized 23andMe to release risk information on three gene mutations linked to increased breast cancer risk.

The changing landscape around the release of health information by direct-to-consumer genetic testing services prompts a number of questions: Do people understand the information conveyed through these tests? What are the effects — mentally, behaviorally and otherwise — of DTC genetic test results on consumers?

This roundup highlights research on these topics. Generally, these tests lead to modest-to-no change in user behavior. Some, however, report increased exercise, more doctor visits and dietary changes. This piece also features research on user motivations for purchasing these tests, which might shed light on subsequent interpretations of and actions stemming from results. Lastly, it includes research on a less-researched consequence of DTC testing: what happens to users’ data at the hands of these services.


Research reviews

Internet-Based Direct-to-Consumer Genetic Testing: A Systematic Review
Covolo, Loredana; et al. Journal of Medical Internet Research, 2015. DOI: 10.2196/jmir.4378.

Results: “In the final sample, 118 articles were identified. Articles were summarized in five categories according to their focus on (1) knowledge of, attitude toward use of, and perception of direct-to-consumer genetic tests (DTC-GT) (n=37), (2) the impact of genetic risk information on users (n=37), (3) the opinion of health professionals (n=20), (4) the content of websites selling DTC-GT (n=16), and (5) the scientific evidence and clinical utility of the tests (n=14). Most of the articles analyzed the attitude, knowledge, and perception of DTC-GT, highlighting an interest in using DTC-GT, along with the need for a health care professional to help interpret the results. The articles investigating the content analysis of the websites selling these tests are in agreement that the information provided by the companies about genetic testing is not completely comprehensive for the consumer. Given that risk information can modify consumers’ health behavior, there are surprisingly few studies carried out on actual consumers and they do not confirm the overall concerns on the possible impact of DTC-GT. Data from studies that investigate the quality of the tests offered confirm that they are not informative, have little predictive power, and do not measure genetic risk appropriately.”

Direct-to-Consumer Genetic Testing and Personal Genomics Services: A Review of Recent Empirical Studies
Roberts, J. Scott; Ostergren, Jenny. Current Genetic Medicine Reports, 2013. PMID: 24058877.

Abstract: “Direct-to-consumer genetic testing (DTC-GT) has sparked much controversy and undergone dramatic changes in its brief history. Debates over appropriate health policies regarding DTC-GT would benefit from empirical research on its benefits, harms, and limitations. We review the recent literature (2011-present) and summarize findings across (1) content analyses of DTC-GT websites, (2) studies of consumer perspectives and experiences, and (3) surveys of relevant health care providers. Findings suggest that neither the health benefits envisioned by DTC-GT proponents (e.g., significant improvements in positive health behaviors) nor the worst fears expressed by its critics (e.g., catastrophic psychological distress and misunderstanding of test results, undue burden on the health care system) have materialized to date. However, research in this area is in its early stages and possesses numerous key limitations. We note needs for future studies to illuminate the impact of DTC-GT and thereby guide practice and policy regarding this rapidly evolving approach to personal genomics.”

Direct-to-Consumer Personal Genome Testing and Cancer Risk Prediction
Bellcross, Cecelia A.; et al. The Cancer Journal, 2012. DOI: 10.1097/PPO.0b013e3182610e38.

Abstract: “The literature regarding consumer awareness and utilization is explored, including understanding, expectations, and behavioral and psychological responses to DTC genomic risk prediction. Primary care provider and genetic professional knowledge and perceptions of DTC genomic profiling are also addressed. Ethical and scientific controversy surrounding the DTC genetic testing industry is presented, along with policy recommendations, regulatory actions, and the changing landscape of the DTC genetic testing market in response. Although our understanding of the human genome holds much promise in the realm of cancer prevention and treatment, DTC genomic profiling for cancer risk prediction is unlikely in its current form to have any significant impact on the health of the public. Time will tell if the next venture in genomic medicine, whole genome sequencing, will be accompanied by the translational research and emphasis on public/provider education required to ensure its successful application toward reducing the burden of cancer at a population level.”

Genomic Information as a Behavioral Health Intervention: Can It Work?
Bloss, Cinnamon S.; Madlensky, Lisa; Schork, Nicholas J.; Topol, Eric J. Personalized Medicine, 2011. DOI: 10.2217/pme.11.73.

Abstract: “Individuals can now obtain their personal genomic information via direct-to-consumer genetic testing, but what, if any, impact will this have on their lifestyle and health? A recent longitudinal cohort study of individuals who underwent consumer genome scanning found minimal impacts of testing on risk-reducing lifestyle behaviors, such as diet and exercise. These results raise an important question: is personal genomic information likely to beneficially impact public health through motivation of lifestyle behavioral change? In this article, we review the literature on lifestyle behavioral change in response to genetic testing for common disease susceptibility variants. We find that only a few studies have been carried out, and that those that have been done have yielded little evidence to suggest that the mere provision of genetic information alone results in widespread changes in lifestyle health behaviors. We suggest that further study of this issue is needed, in particular studies that examine response to multiplex testing for multiple genetic markers and conditions. This will be critical as we anticipate the wide availability of whole-genome sequencing and more comprehensive phenotyping of individuals. We also note that while simple communication of genomic information and disease susceptibility may be sufficient to catalyze lifestyle changes in some highly motivated groups of individuals, for others, additional strategies may be required to prompt changes, including more sophisticated means of risk communication (e.g., in the context of social norm feedback) either alone or in combination with other promising interventions (e.g., real-time wireless health monitoring devices).”


Motivations for testing

Direct-to-Consumer Genetic Testing: User Motivations, Decision Making, and Perceived Utility of Results
Roberts, J. Scott; et al. Public Health Genomics, 2017. DOI: 10.1159/000455006.

Findings: “Prior to testing, direct-to-consumer personal genomic testing (DTC-PGT) consumers were as interested in ancestry (74 percent very interested) and trait information (72 percent) as they were in disease risks (72 percent). Among disease risks, heart disease (68 percent very interested), breast cancer (67 percent), and Alzheimer disease (66 percent) were of greatest interest prior to testing. Interest in disease risks was associated with female gender and poorer self-reported health (p < 0.01). Many consumers (38 percent) did not consider the possibility of unwanted information before purchasing services; this group was more likely to be older, male, and less educated (p < 0.05). After receiving results, 59 percent of respondents said test information would influence management of their health; 2 percent reported regret about seeking testing and 1 percent reported harm from results.”


Cancer risk

Personal Genomic Testing for Cancer Risk: Results from the Impact of Personal Genomics Study
Gray, Stacy W.; et al. Journal of Clinical Oncology, 2017. DOI: 10.1200/JCO.2016.67.1503.

Results: “Of the 1,042 customers who completed baseline and 6-month surveys (response rate, 71.2 percent), 762 had complete cancer-related data and were analyzed. Most customers reported that learning about their genetic risk of cancers was a motivation for testing (colorectal, 88 percent; prostate, 95 percent; breast, 94 percent). No customers tested positive for pathogenic mutations in highly penetrant cancer susceptibility genes. A minority of individuals received elevated single nucleotide polymorphism-based PGT cancer risk estimates (colorectal, 24 percent; prostate, 24 percent; breast, 12 percent). At 6 months, customers who received elevated PGT cancer risk estimates were not significantly more likely to change their diet, exercise, or advanced planning behaviors or engage in cancer screening, compared with individuals at average or reduced risk. Men who received elevated PGT prostate cancer risk estimates changed their vitamin and supplement use more than those at average or reduced risk (22 percent v 7.6 percent, respectively; adjusted odds ratio, 3.41; 95 percent CI, 1.44 to 8.18). Predictors of 6-month behavior include baseline behavior (exercise, vitamin or supplement use, and screening), worse health status (diet and vitamin or supplement use), and older age (advanced planning, screening).”

The Impact of Direct-to-Consumer Personal Genomic Testing on Perceived Risk of Breast, Prostate, Colorectal, and Lung Cancer: Findings from the PGen Study
Carere, Deanna Alexis; et al. BMC Medical Genomics, 2015. DOI: 10.1186/s12920-015-0140-y.

Findings: “We have quantified the effect on consumer risk perception of returning genetic-based cancer risk information directly to consumers without clinician mediation. Provided via personal genomic testing (PGT), this information has a measurable but modest effect on perceived cancer risk, and one that is in some cases modified by consumers’ non-genetic risk context. Our observations of modest marginal effect sizes, infrequent extreme changes in perceived risk, and a pattern of diminishing impact with time, suggest that the ability of PGT to effect changes to cancer screening and prevention behaviors may be limited by relatively small changes to perceived risk.”


Other effects

Behavioral Changes, Sharing Behavior and Psychological Responses After Receiving Direct-to-Consumer Genetic Test Results: A Systematic Review and Meta-Analysis
Stewart, Kelly F. J.; et al. Journal of Community Genetics, 2018. DOI: 10.1007/s12687-017-0310-z.

Abstract: “After selection, 19 articles were included involving 11 unique studies. Seven studies involved actual consumers who paid the retail price, whereas four included participants who received free genetic testing as part of a research trial (non-actual consumers). In meta-analysis, 23 percent had a positive lifestyle change. More specifically, improved dietary and exercise practices were both reported by 12 percent, whereas 19 percent quit smoking. Seven percent of participants had subsequent preventive checks. Thirty-three percent shared their results with any health care professional and 50 percent with family and/or friends. Sub-analyses show that behavior change was more prevalent among non-actual consumers, whereas sharing was more prevalent among actual consumers. Results on psychological responses showed that anxiety, distress and worry were low or absent and that the effect faded with time. Direct-to-consumer genetic testing has potential to be effective as a health intervention, but the right audience needs to be addressed with tailored follow-up. Research is needed to identify consumers who do and do not change behavior or experience adverse psychological responses.”

Prescription Medication Changes Following Direct-to-Consumer Personal Genomic Testing: Findings from the Impact of Personal Genomics (PGen) Study
Carere, Deanna Alexis; et al. Genetics in Medicine, 2017. DOI: 10.1038/gim.2016.141.

Conclusion: “Receipt of pharmacogenomic results indicating an atypical drug response is common with direct-to-consumer personal genomic testing and is associated with prescription medication changes; however, fewer than 1 percent of consumers report unsupervised changes at 6 months after testing.”

Diet and Exercise Changes Following Direct-to-Consumer Personal Genomic Testing
Nielsen, Daiva Elena; et al. BMC Medical Genomics, 2017. DOI: 10.1186/s12920-017-0258-1.

Findings: “In a longitudinal study of actual direct-to-consumer personal genomic testing (DTC-PGT) customers, we found modest, but statistically significant, increases in self-reported vegetable consumption and strength exercise frequency post-PGT.”

Utilization of Genetic Counseling after Direct-to-Consumer Genetic Testing: Findings from the Impact of Personal Genomics (PGen) Study
Koeller, Diane R.; et al. Journal of Genetic Counseling, 2017. DOI: 10.1007/s10897-017-0106-7.

Abstract: “Direct-to-consumer personal genomic testing (DTC-PGT) results lead some individuals to seek genetic counseling (GC), but little is known about these consumers and why they seek GC services. We analyzed survey data pre- and post-PGT from 1,026 23andMe and Pathway Genomics customers. Participants were mostly white (91 percent), female (60 percent), and of high socioeconomic status (80 percent college educated, 43 percent household income of ≥$100,000). After receiving PGT results, 43 participants (4 percent) made or planned to schedule an appointment with a genetic counselor; 390 (38 percent) would have used in-person GC had it been available. Compared to non-seekers, GC seekers were younger (mean age of 38 vs 46 years), more frequently had children <18 (26 percent vs 16 percent), and were more likely to report previous GC (37 percent vs 7 percent) and genetic testing (30 percent vs 15 percent). In logistic regression analysis, seeking GC was associated with previous GC use (OR = 6.5, CI = 3.1-13.8), feeling motivated to pursue DTC-PGT for health reasons (OR = 4.3, CI = 1.8-10.1), fair or poor self-reported health (OR = 3.1, CI = 1.1-8.3), and self-reported uncertainty about the results (OR = 1.8, CI = 1.1-2.7). These findings can help GC providers anticipate who might seek GC services and plan for clinical discussions of DTC-PGT results.”

Consumer Perspectives on Access to Direct-to-Consumer Genetic Testing: Role of Demographic Factors and the Testing Experience: Consumer Perspectives on Access to Direct-to-Consumer Genetic Testing
Gollust, Sarah E.; et al. The Milbank Quarterly, 2017. DOI: 10.1111/1468-0009.12262.


  • “The policy context of direct‐to‐consumer personal genomic testing (DTC‐PGT) has been evolving over the last decade, with little empirical data available about consumers’ perspectives.
  • A majority of consumers of DTC‐PGT supported expanded access to services and their integration into the medical context and opposed more governmental regulation.
  • Consumers’ attitudes about access to services and regulation did not vary based on the specific genetic risk information they received from companies, but may vary based on whether consumers perceived their DTC experience negatively.”

Influence of Individual Differences in Disease Perception on Consumer Response to Direct-to-Consumer Genomic Testing: Disease Perception and Genetic Risk
Boeldt, D. L.; et al. Clinical Genetics, 2015. DOI: 10.1111/cge.12419.

Abstract: “Individuals who undergo multiplex direct‐to‐consumer (DTC) genomic testing receive genetic risk results for multiple conditions. To date, research has not investigated the influence of individual differences in disease perceptions among consumers on testing outcomes. A total of 2,037 participants received DTC genomic testing and completed baseline and follow‐up surveys assessing disease perceptions and health behaviors. Participants were asked to indicate their most feared disease of those tested. Perceived seriousness and controllability of the disease via lifestyle or medical intervention were assessed. Participants most frequently reported heart attack (19.1 percent) and Alzheimer’s disease (18.6 percent) as their most feared disease. Perceived seriousness and control over the feared disease both influenced response to DTC genomic testing. Greater perceived seriousness and diminished perceived control were associated with higher, but not clinically significant levels of anxiety and distress. In some cases these associations were modified by genetic risk. No significant associations were observed for diet, exercise and screening behaviors. Individual differences in disease perceptions influence psychological outcomes following DTC genomic testing. Higher perceived seriousness may make a consumer more psychologically sensitive to test results and greater perceived control may protect against adverse psychological outcomes. Findings may inform development of educational and counseling services.”

How Well Do Customers of Direct-to-Consumer Personal Genomic Testing Services Comprehend Genetic Test Results? Findings from the Impact of Personal Genomics Study
Ostergren, Jenny E.; et al. Public Health Genomics, 2015. DOI: 10.1159/000431250.

Findings: “Most customers accurately interpreted the health implications of personal genetic testing (PGT) results; however, comprehension varied by demographic characteristics, numeracy and genetic knowledge, and types and format of the genetic information presented. Results suggest a need to tailor the presentation of PGT results by test type and customer characteristics.”

Characteristics of Genomic Test Consumers Who Spontaneously Share Results With Their Health Care Provider
Darst, Burcu F.; et al. Health Communication, 2014. DOI: 10.1080/10410236.2012.717216.

Abstract: “The purpose of this study was to evaluate the characteristics of direct-to-consumer (DTC) genomic test consumers who spontaneously shared their test results with their health care provider. Utilizing data from the Scripps Genomic Health Initiative, we compared demographic, behavioral, and attitudinal characteristics of DTC genomic test consumers who shared their results with their physician or health care provider versus those who did not share. We also compared genomic risk estimates between the two groups. Of 2,024 individuals assessed at approximately 6 months post testing, 540 individuals (26.5 percent) reported sharing their results with their physician or health care provider. Those who shared were older (p < .001), had a higher income (p = .01), were more likely to be married (p = .005), and were more likely to identify with a religion (p = .004). As assessed prior to undergoing testing, sharers also reported higher levels of exercise (p = .003), lower fat intake (p = .02), fewer overall concerns about testing (p = .001), and fewer concerns related to the privacy of their genomic information (p = .03). The genomic disease risk estimates disclosed were not associated with sharing. Thus, in a DTC genomic testing context, physicians and other health care providers may be more likely to encounter patients who are more health conscious and have fewer concerns about the privacy of their genomic information. Genomic risk itself does not appear to be a primary determinant of sharing behavior among consumers.”

Direct-to-Consumer Pharmacogenomic Testing is Associated with Increased Physician Utilization
Bloss, Cinnamon S.; Schork, Nicholas J.; Topol, Eric J. Journal of Medical Genetics, 2014. DOI: 10.1136/jmedgenet-2013-101909.

Abstract: “We recruited a sample of adults who purchased a DTC genomic test and had previously received their genomic test results for complex disease risk. All participants additionally underwent pharmacogenomic (PGx) testing. At follow-up, to assess the impact of PGx testing on consumer behavior, healthcare utilization and psychological status were compared between approximately a third of participants who had received their PGx results and the remaining two-thirds of participants who were still awaiting results. The PGx test included genetic testing for drug effectiveness or risk of side effects for 12 medications. …At follow-up, there were 481 PGx test recipients and 844 non-recipients still awaiting results. PGx test recipients had more physician visits (p=0.04) and were more likely to share their results with their physician (p=0.001). Both groups showed a decrease in anxiety symptoms from baseline to follow-up, with a trend for PGx recipients to show less of a decrease compared with non-recipients (p=0.10). PGx recipients were more likely to report that their physician ordered additional tests (p=0.01) based on their genomic test. There were no group differences in follow-up test-related distress (p=0.67).”

Impact of Direct-to-Consumer Genomic Testing at Long Term Follow-Up
Bloss, Cinnamon S.; et al. Journal of Medical Genetics, 2013. DOI: 10.1136/jmedgenet-2012-101207.

Conclusions: “Over a third of DTC genomic test recipients shared their results with their own physician during an approximate 1-year follow-up period, and this sharing was associated with higher screening test completion. Genomic testing was not associated with long term psychological risks, and most participants reportedly perceived the test to be of high personal utility.”

Effect of Direct-to-Consumer Genomewide Profiling to Assess Disease Risk
Bloss, Cinnamon S.; Schork, Nicholas J.; Topol, Eric J. New England Journal of Medicine, 2011. DOI: 10.1056/NEJMoa1011893.

Conclusions: “In a selected sample of subjects who completed follow-up after undergoing consumer genomewide testing, such testing did not result in any measurable short-term changes in psychological health, diet or exercise behavior, or use of screening tests. Potential effects of this type of genetic testing on the population at large are not known.”

Self Diagnosis of Lynch Syndrome Using Direct to Consumer Genetic Testing: A Case Study
Roberts, Maegan E., et al. Journal of Genetic Counseling, 2011. DOI: 10.1007/s10897-011-9356-y.

Abstract: “We are reporting what we believe to be the first published case of patient initiated direct to consumer (DTC) genetic testing to test for the presence of a known familial mutation. Our client in this case is from a known MSH2 family; both his/her parent and associated grandparent have previously tested positive for the known familial MSH2 mutation. Using 23andme’s “family inheritance genome-wide comparison” option we were able to determine that our client most likely inherited the known familial MSH2 mutation without pursuing single site genetic testing. Our client pursued DTC genetic testing instead of single site genetic testing due to the fear of genetic discrimination. This case shows that patients are still fearful of genetic discrimination, despite the passage of the Genetic Information Nondiscrimination Act (GINA), and that DTC genetic testing may be useful despite the overall negative feeling towards this type of testing in the genetic counseling community.”

All Your Data (Effectively) Belong to Us: Data Practices Among Direct-to-Consumer Genetic Testing Firms
Laestadius, Linnea I.; Rich, Jennifer R.; Auer, Paul L. Genetics in Medicine, 2017. DOI: 10.1038/gim.2016.136.

Results: “Although most companies met guidelines related to transparency regarding security protocols, storage procedures, and third-party disclosures, few met guidelines regarding sharing risks from data disclosures. Additionally, few companies disclosed how long data would be kept for services or research. Use of data for research was frequently mentioned only in privacy policies and terms of service documents, and only two-thirds of companies required an additional consent to use consumer data for health-related research.”

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