medwireNews: A randomized trial shows that knowledge of personal genetic or phenotypic risk for type 2 diabetes is not sufficient to motivate healthy adults to alter their activity levels.
On the other hand, receiving a personalized risk assessment also did not cause them any worry, report Job Godino (University of Cambridge School of Clinical Medicine, UK) and co-researchers.
“This is an important observation, given the expectations that such communications might facilitate behavior change and the concerns about the potential adverse psychological consequences of predictive genetic testing,” they write in PLOS Medicine.
All 550 study participants (average age 47 years) received healthy lifestyle advice, but 184 were also informed of their genetic risk for type 2 diabetes, based on 23 single nucleotide polymorphisms, and 182 were informed of their phenotypic risk, based on the Cambridge Diabetes Risk Score.
The team presented participants’ risk information both as a percentage and as below average/average/above average, “in a manner similar to that of several direct-to-consumer genetic testing companies.”
Participants did not report increased worry or anxiety after being presented with the risk information, but, notably, their perceptions of their own risk actually fell, from an average of 39.2 to 32.9 (on a scale of 0 to 100) in the genetic risk group and from 38.8 to 33.4 in the phenotypic risk group.
“[T]he volunteers tended to overestimate their risk at baseline and may therefore have been somewhat reassured by the information that they received, albeit not to the extent that they adopted unhealthy behaviors,” suggest the researchers.
However, the participants also did not improve their physical activity energy expenditure, measured objectively using the Actiheart for 6 consecutive days and nights during the 8 weeks of follow-up, either overall or in most subgroups.
The only exception was that women presented with their genetic risk were more likely than men to increase their physical activity levels, “raising the possibility that genetic risk information may be more influential among women than among men.”
The researchers observe that any impact of risk communication is offset by “an environment in which there are many impediments to being physically active and eating a healthy diet.”
They say their findings support “a shift in focus […] away from interventions solely based on provision of information and advice to individuals towards interventions that target the wider collective determinants of disease.”
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