Knowing genetic makeup can make you more receptive to lifestyle changes

A small dose of your genetic information is likely to make you more sensitive towards weight loss and exercise, reveals a new study.

David Kaufman of the Genetics and Public Policy Centre quizzed 1048 customers who had ordered genome scans.

As many as 34% of respondents said they were being more careful about their diet, 14% said they were doing more exercise, and 16% had changed their medications or dietary supplements.

"I was surprised at the number of people who said they'd made changes already," New Scientist quoted Kaufman, as saying.

However, the 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.

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.

However, Toby Jayaratne, a specialist in health behaviour at the University of Michigan, 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.

Customers of personal genomics firms are typically relatively wealthy and well-educated.

"They tend to be people who are highly motivated health-seekers and science geeks," said Barbara Bernhardt of the University of Pennsylvania in Philadelphia, which conducted detailed interviews with 60 volunteers in the Coriell Personalised Medicine Collaborative.

Bernhardt's findings also suggested 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 "relative risk" figures provided by personal genomics firms.

The findings were presented at the annual meeting of the American Society of Human Genetics (ASHG) in Washington DC.