Letting your imagination run wild – genetic testing for risk of weight gain

These are exciting times for people working in genetics.  The field has become trendy.  ‘DNA’, ‘genes’ and ‘genetic code’ are no longer specialist terms, but used casually in everyday language. The media love ‘The gene for’ stories  and attributing individual differences to biology and less to environment is becoming commonplace.  I recently read an interview with a singer who explained that she could not imagine being anything else but a singer, because singing ‘was in her DNA’. If this still does not convince you: The pop band ‘Little Mix’ recently released a new song titled ‘DNA’ (http://www.youtube.com/watch?v=D3h-lLj3xv4).

Why the fascination with genes?  To a degree, it appears to stem from the inherent assumption that our genes can give us insights into ourselves that would otherwise remain inaccessible. Although our DNA is  99.9% identical, this is not interesting – it is all about the tiny bit of difference, the bit which sets us apart and makes us unique.

Companies have been quick to capitalise on our curiosity of what would be possible once the Human Genome was decoded.  Genetic tests for an array of traits and conditions, including those that are common and driven by lifestyle, such as obesity or heart disease, are already available over the Internet.  So far, we are not sure about the effects of giving this type of information to people. It could be that people will use it to prevent the condition. Alternatively, it could be that they become fatalistic or complacent. I have written in more detail about the current debate in a previous blogpost ( http://tinyurl.com/bve6y2m).  I hope to add some evidence to the debate by looking at the psychological and behavioural consequences of receiving genetic test feedback using obesity as an example for a very common, very complex condition.

Because we do not know yet how people react to knowing about their genetic susceptibility to weight gain, it would be unwise to give them this information right away.  Instead, we set up an online study where people were asked to imagine their reactions to receiving a ‘higher-risk’ or an ‘average-risk’ genetic test result for weight gain. They were then asked questions on a broad range of feelings and behaviours. We included 2 sets of people, nearly 400 students, who were predominantly of healthy weight and almost as many people from the general public who were or had been overweight.

Results showed that people in both groups reported to be more motivated to make lifestyle changes after imagining getting a ‘higher’ genetic risk result than after imagining getting an ‘average’ genetic risk result. On average, negative feelings and feelings of fatalism were anticipated to be very low and did not differ between risk scenarios. Those who were already overweight or obese were more likely to think that in comparison with an ‘average’ genetic risk result, receiving a ‘higher’ genetic risk result would offer them an explanation for their weight status.  Finally, people in both groups thought that they would be more likely to seek out information about what their result means in the ‘higher-risk’ than in the ‘average-risk’ scenario.

These findings are good news, because they suggest that giving people feedback for susceptibility to weight gain is unlikely to have unanticipated negative effects, and may even be motivating.  Furthermore, people who are already overweight may also benefit from genetic feedback.  However, these findings may not hold up once people are actually given genetic test feedback, because they only tell us about what people think they might do – and people find it generally quite difficult to imagine to be negatively affected by an event.  The next step is now to give people ‘real’ genetic feedback for risk of weight gain to discover the effect of this type of information.

 

Reference:

Meisel, S. F., Walker, C., & Wardle, J. (2011). Psychological Responses to Genetic Testing for Weight Gain: A Vignette Study. Obesity (Silver Spring); 20 (3).DOI: 10.1038/oby.2011.324