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Genetic testing doesn’t change how most people behave, study finds

James Bareham

Genetic testing offers people insight into the types of diseases they are most likely to develop — but a new study suggests most people do not alter their lifestyles based on this information. These tests — known as genome sequencing — analyze a person's DNA, telling patients about their known risk for diseases like cancer or diabetes. But being told you’re at a higher risk for lung cancer doesn’t seem to motivate anyone to quit smoking, this study suggests. Because of this, the study authors argue that genetic testing should not be used as a tool for improving people's health.

Today’s finding came from pulling data from 18 other studies that followed people after they received the results of genetic tests. Receiving information about genetic risks didn’t inspire people to eat differently, exercise more, or stop smoking, according to today’s report in the British Medical Journal. Nor were they likely to wear more sunscreen or drink less booze. In fact, no significant behavioral effects for genetic testing were found at all. "Expectations have been high that giving people information about their genetic risk will empower them to change their behavior - to eat more healthily or to stop smoking, for example - but we have found no evidence that this is the case," study author Theresa Marteau, director of behavior and health research at the University of Cambridge, said in a press release.

"The idea that providing genetic risk information is going to be transformative to everyone seems unlikely."

Genetic testing, which the National Institutes of Health says costs anywhere from $100 to $2,000, has become much more accessible as commercial testing companies such as 23andMe and Sure Genomics have sprung up. These companies are not allowed to share disease risk estimates directly with US consumers thanks to the Food and Drug Administration, but 23andMe was recently approved to offer testing for 36 inherited disorders. Today’s study didn’t specify whether the genetic testing results were purely from academic sequencing, or if any of these companies had supplied the tests.

Genetic testing doesn’t get people to change their behavior for the better, but it doesn't have any known negative effects either. Knowing the results of these tests didn't change people's depression or anxiety levels. And there's no indication that testing inspires people to pick up risky or dangerous health habits either, the study found.

That may be because having a genetic predisposition to a disease is common, says to Brian Zikmund-Fisher, an associate professor of health behavior and education at the University of Michigan. But the most common risk factors usually don't raise a person's chances of getting a disease by a significant amount, he said. It's possible that some of the patients in the study had substantially higher disease risks based on their DNA profile, but those patients tend to be rare. "It’s still likely that communicating this type of information is very valuable to some people, it’s just that there aren’t that many of those people," Zikmund-Fisher told The Verge. "The idea that providing genetic risk information is going to be transformative to everyone seems unlikely."