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Genetic testing results don't change how most people behave

Genetic tests that let people know if they are at a higher risk for developing certain diseases are becoming more common, but what do people do when they learn the results? Armed with that knowledge, you might expect that they'd take action to reduce their risk. But a new study finds that doesn't usually happen.

Reading an individual's entire DNA -- known as genome sequencing -- is a controversial technique that provides people with information on whether or not they carry genes known to increase their risk of certain diseases, such as cancer or heart disease. Carrying these variants does not necessarily mean the person will go on to develop that condition, but if individuals know they are at a greater risk, they can make an informed choice to modify their behavior to help improve their odds.

Researchers from England set out to see if that notion is true. They analyzed over a dozen studies involving more than 6,100 adults ages 30 to 56 that looked at whether having the results of their DNA tests available to them influenced their behavior.

The results showed no evidence that people adopted healthier lifestyle changes after receiving their results.

For example, smokers who learned they were at an increased genetic risk of developing lung cancer were no more likely to stop smoking than those who did not carry these genetic variants. Also, telling a middle-aged man or women that they had a greater chance of developing diabetes did not influence them to adopt a regular exercise routine. The findings were published this week in The BMJ.

"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," lead researcher Theresa Marteau, said in a statement.

However, she pointed out that the research doesn't support concerns that genome sequencing discourages people from changing their behavior.

Over the last decade, several companies began selling DNA tests directly to consumers in the U.S., Canada, and Europe. In 2013, the FDA ordered the company 23andme to stop selling its testing kit for medical purposes due to accuracy concerns, but it resumed offering some health services last October.

Despite their findings, the study authors note that DNA testing may still play a role in improving people's health, especially when it comes to providing instruction to their doctors.

"DNA testing, alone or in combination with other assessments of disease risk, may help clinicians identify individuals at greatest risk and allow them to target interventions such as screening tests, surgery, and drug treatments," said Marteau's co-author Dr. Gareth Hollands.

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