Direct to consumer genetic testing in Denmark-public knowledge, use, and attitudes.

Direct to consumer genetic testing (DTC-GT) is offered by commercial companies, but the use in the general population has only been sparsely investigated. A questionnaire was sent to 2013 representative Danish citizens asking about their awareness and use of DTC-GT. Individuals who had undergone a genetic test were interviewed to determine if the results had been understood correctly. A pilot study with 2469 questionnaires was performed before this study. In total, 45.4% of the individuals (n = 913/2013) had knowledge about DTC-GT and 2.5% (n = (18 + 5)/913) previously had a genetic test by a private company and 5.8% through the public health care system (n = (48 + 5)/913). Curiosity about own genetic information was the most frequent motivation (40.9%, n = 9/22) as well as knowledge of ancestry (36.4%, n = 8/22) and advice about lifestyle, exercise, or diet (36.4%, n = 8/22). Test of own disease risk was given as a reason in 27.3% (n = 6/22) and seeking possible explanation of specific symptoms in 13.6% (n = 3/22). 50% (n = 11/22) answered that they had become concerned after the test, and 17.4% (n = 4/23) had consulted their GP. Interviews in a subset of respondents from the pilot study revealed problems with understanding the results. One problem was how to interpret the genetic test results with respect to individual risk for a disease. For example, the difference between disease causing genetic variants in monogenetic diseases versus statistical risks by SNPs in multifactorial diseases was not understood by the respondents.