Genetic Risk of Disease Results Don’t Change Health-Related Behaviors

By Lori Solomon, Editor, Diagnostic Testing & Emerging Technologies

Communicating genetic risk of disease estimates does not impact individuals’ health related behaviors, according to a review published March 15 in the British Medical Journal. Of the seven evaluated health behaviors, the absence of impact was strongest for smoking cessation in light of lung cancer risk and physical activity related to diabetes risk. The authors say that these results do not support the use of genetic testing or the search for risk-conferring gene variants for common, complex diseases for the purpose of promoting risk-reducing behavior.

The authors say these findings are pertinent given demand for direct-to-consumer tests for a range of common complex disorders. While the availability of these tests is currently limited in the United States, they are sold in Canada, the United Kingdom, and other European countries.

“As the science develops, it is increasingly possible to provide information about multiple single genes, each relating to different disease risks, and also to aggregate multiple risk loci and identify patterns of characteristics across multiple genes that in combination confer increased risks of one or more diseases,” writes lead author Gareth Hollands, from University of Cambridge in the United Kingdom.”However, DNA based disease risk estimates will only translate into health benefits if acting on them modifies disease outcomes, and if those informed of these genetic risks undertake the relevant actions.”

The researchers conducted a systematic literature review to identify 18 randomized and quasi-randomized controlled trials involving adults with one group that received personalized DNA-based estimates of disease risk for conditions where risk could be reduced by behavior change. Seven behavioral outcomes were assessed, including: smoking cessation (six studies; n=2,663), diet (seven studies; n=1,784), physical activity (six studies; n=1,704), alcohol use (three studies; n=239), screening or behavioral support program attendance (two studies; n=891), sun protection behavior (one study; n=73), and medication use (one study; n=162).

The meta-analysis found no significant effects of communicating DNA-based risk estimates on any of the behavior modifications. Similarly, there was no effect on the secondary outcome of motivation to change behavior.

“The available evidence does not provide support for the expectations raised by researchers and proponents of personalized medicine as well as direct-to-consumer testing companies that the receipt of results from DNA based tests for gene variants that confer increased risk of common complex diseases motivates behavior change,” write the authors, who additionally say, “Concerns that communicating DNA based disease risk estimates may demotivate behavior change are also unsupported by the results of this review.”