The highest profile direct-to-consumer genetic testing company in the world, 23andMe, has opened shop in Canada. In addition to providing information about your genetic ancestry (turns out I am 100% Irish), 23andMe will, after your genetic information is pulled from the required tube of spit, provide you with a whole bunch of genetic risk information that may, or may not, be relevant to your health.
Should Canadians care? Should Health Canada convene an emergency session to shut down 23andMe, just as the FDA did in the United States in 2013?
I have been following the genetic testing story for years and one clear and consistent theme has emerged: there is a lot of hype and misinformation on both sides of the debate.
Let’s start with what the evidence tells us about promised benefits. At the core of the direct to consumer business model – whether it is 23andMe or one of the many less well-known outfits promising to genetically-personalize your diet, workout or love life – is the idea that receiving your genetic information will empower you to make more informed decisions. You will get your genes tested, find out if you are at increased risk for heart disease or some form of cancer and change your lifestyle. You will go for long runs with your dog. You will eat more fresh fruit and vegetables. You will lose weight, drink in moderation and quit smoking.
Now, I am not going to say that these direct to consumer genetic services are totally ineffective for all. Some may find this information “empowering”. (Heck, some people feel empowered by their horoscope.) But there is absolutely no reason to believe that providing genetic risk information will, for most, lead to healthier decisions or motivate these kinds of changes.
First, the vast majority of the information provided by these companies – or by genetic testing generally – simply isn’t that predictive. Indeed, I got my genes tested by 23andMe in 2011. It was a fun and intriguing process – a bit like eavesdropping on a couple of strangers talking about you. (They are right! I do have blue eyes, my hair is kinda curly and I am slightly taller than average!) But the information I received from 23andMe was (and will forever remain) far less predictive of future health problems than, say, my weight, blood pressure, family history or postal code.
While there are a few well-known genetic mutations that are highly predictive of a future disease, these mutations are relatively rare. Most genetic risk information is largely useless when set against other, well-established risk factors such as smoking, obesity and inactivity. For example, a recent study out of Cambridge published in PLoS Medicine found that the weight of an individual is far more predictive of type 2 diabetes than genetic risk information. As a result, the authors of the study conclude by noting the “importance of universal rather than targeted [i.e., genetically-informed] approaches to lifestyle intervention.”
Second, we should also not forget how incredibly difficult it is to change behaviour. Providing a bit of risk information – whether it comes from your bathroom weigh scale or a multi-million-dollar gene sequencer – is unlikely to have a large impact on population health. Studies have consistently found that genetic risk does not lead to dramatic changes. To cite just a few examples, it does not seem to help smokers quit or the obese lose weight. And a 2013 study on point came to the conclusion that genetic risk counselling does not significantly alter motivation or adherence to weight loss strategies for individuals at risk for diabetes.
OK, so the benefits – at least in terms of lifestyle changes – seem marginal or non-existent, but what about the harms? Just as there is little evidence that people benefit from receiving genetic risk information, there is also little evidence of significant harm. Studies have found, for example, that people do not freak out when they receive their results and they don’t behave fatalistically to bad genetic news (e.g., “bring on the fries, I’m gonna die anyway!”). In addition, despite lots of hand waving (and fear) to the contrary, there is very little solid evidence of widespread genetic discrimination.
There are, of course, other problems that may be associated with direct to consumer genetic testing, including increased (and perhaps unnecessary) utilization of health care resources and an inappropriate framing of chronic disease as a personal, rather than a social, concern. But our first response to the 23andMe development should be to take a deep breath and dial back the exaggerated claims of benefit and harm. Let’s develop an evidence-based direct to consumer policy.
When I got my results from 23andMe I found out that I am at (ever so slightly) increased risk for a whole bunch of nasty things, including coronary heart disease and various cancers. My personalized advice? Drink in moderation, exercise, watch my weight, don’t smoke and eat a healthy diet that includes lots of fruits and vegetables. Solid. Advice we should all follow. No test required.