Could a small dose of genetic information cure complacency about weight loss and exercise? That鈥檚 the suggestion made by a new study of how information from 鈥減ersonal genomics鈥� companies has influenced their customers.
of the Genetics and Public Policy Center in Washington聽DC quizzed 1048 customers who had ordered genome scans from of Reykjavik, Iceland, of Mountain View, California, or , based in Foster City, California.
Asked about changes in their behaviour between two and six months after receiving the results, 34 per cent of respondents said they were being more careful about their diet, 14 per cent said they were doing more exercise, and 16 per cent had changed their medications or dietary supplements.
Advertisement
鈥淚 was surprised at the number of people who said they鈥檇 made changes already,鈥� says Kaufman, who revealed the results this week at the of the American Society of Human Genetics (ASHG) in Washington聽DC.
That鈥檚 impressive because getting people to adopt more healthy lifestyles is notoriously difficult 鈥� even when family history shows a high risk of conditions like type聽2 diabetes and heart attacks.
Right thing, wrong reasons?
But responses to genetic information may be out of proportion to its actual predictive value. For most common diseases, the genome scans available now explain relatively little about your future risks. In the case of type聽2 diabetes, for example, diet and exercise play a greater role in risk than genetics does, and the DNA variants discovered so far explain only a small proportion of the disease鈥檚 heritability.
Even so, if genetic information has a disproportionate effect in getting people to heed advice that they should be following anyway, that could be a strong force for improving public health.
, a specialist in diabetes prevention at Indiana University in Indianapolis, says he is impressed by reported changes in behaviour, but adds, 鈥淭he question is how long it is sustained.鈥�
Early adopters
Kaufman hopes to run follow-up studies to address that question. Another important issue is whether genetic information will be similarly motivating when it moves outside the self-selecting group who now purchase genome scans and becomes part of mainstream medical practice.
, a specialist in health behaviour at the University of Michigan in Ann Arbor, worries that some people will adopt a fatalistic attitude if told that they have a genetic predisposition to a particular disease, and become less likely to act to improve their health. This is more likely among poor and socially disadvantaged people, she adds.
Customers of personal genomics firms are typically relatively wealthy and well-educated. The same is true of those who have joined academic studies of the effects of providing genetic information on health behaviour. 鈥淭hey tend to be people who are highly motivated health-seekers and science geeks,鈥� says of the University of Pennsylvania in Philadelphia, who has conducted detailed interviews with 60 volunteers in the , a pioneering effort to study the medical value of genetic information.
Risk judgements
Bernhardt鈥檚 findings, also revealed at the ASHG meeting, suggest that people tend to focus mainly on whether their genetic risks for each condition are higher or lower than average, rather than paying close attention to the size of those risks. This means that people might be paying undue attention to risks that are not actually significantly elevated.
Kaufman, meanwhile, has found that a minority of his respondents misunderstand the 鈥渞elative risk鈥� figures provided by personal genomics firms, particularly when the risks are below average 鈥� a relative risk of 0.8, for instance, indicates that the person tested is 20聽per cent less likely to develop a condition than a typical member of the same population.
However, despite these glitches, he finds little evidence that people are misinterpreting genetic information in ways that might be dangerous to their health. Those who said they had changed medications, for instance, had overwhelmingly done so in consultation with their doctor.
鈥淲e don鈥檛 give people enough credit to people鈥檚 abilities to decide what鈥檚 useful to them,鈥� Kaufman suggests. 鈥淧eople who get their data are generally pleased with it, and they respond in generally positive ways.鈥�
