title: Lifestyle Advice Combined with Personalized Estimates of Genetic or Phenotypic Risk of Type 2 Diabetes, and Objectively Measured Physical Activity: A Randomized Controlled Trial.
abstract: BACKGROUND
  Information about genetic and phenotypic risk of type 2 diabetes is now widely available and is being incorporated into disease prevention programs. Whether such information motivates behavior change or has adverse effects is uncertain. We examined the effect of communicating an estimate of genetic or phenotypic risk of type 2 diabetes in a parallel group, open, randomized controlled trial.
  
  
  RESULTS
  We recruited 569 healthy middle-aged adults from the Fenland Study, an ongoing population-based, observational study in the east of England (Cambridgeshire, UK). We used a computer-generated random list to assign participants in blocks of six to receive either standard lifestyle advice alone (control group, n = 190) or in combination with a genetic (n = 189) or a phenotypic (n = 190) risk estimate for type 2 diabetes (intervention groups). After 8 wk, we measured the primary outcome, objectively measured physical activity (kJ/kg/day), and also measured several secondary outcomes (including self-reported diet, self-reported weight, worry, anxiety, and perceived risk). The study was powered to detect a between-group difference of 4.1 kJ/kg/d at follow-up. 557 (98%) participants completed the trial. There were no significant intervention effects on physical activity (difference in adjusted mean change from baseline: genetic risk group versus control group 0.85 kJ/kg/d (95% CI -2.07 to 3.77, p = 0.57); phenotypic risk group versus control group 1.32 (95% CI -1.61 to 4.25, p = 0.38); and genetic risk group versus phenotypic risk group -0.47 (95% CI -3.40 to 2.46, p = 0.75). No significant differences in self-reported diet, self-reported weight, worry, and anxiety were observed between trial groups. Estimates of perceived risk were significantly more accurate among those who received risk information than among those who did not. Key limitations include the recruitment of a sample that may not be representative of the UK population, use of self-reported secondary outcome measures, and a short follow-up period.
  
  
  CONCLUSIONS
  In this study, we did not observe short-term changes in behavior associated with the communication of an estimate of genetic or phenotypic risk of type 2 diabetes. We also did not observe changes in worry or anxiety in the study population. Additional research is needed to investigate the conditions under which risk information might enhance preventive strategies. (Current Controlled Trials ISRCTN09650496; Date applied: April 4, 2011; Date assigned: June 10, 2011).
  
  
  BACKGROUND
  The trial is registered with Current Controlled Trials, ISRCTN09650496.
authors.affiliation: MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.|Center for Wireless and Population Health Systems, Department of Family Medicine and Public Health and Calit2's Qualcomm Institute, University of California, San Diego, La Jolla, California, United States of America.
authors.forename: Job G
authors.identifier: http://orcid.org/0000-0002-4852-6277
authors.initials: JG
authors.lastname: Godino
authors.affiliation: MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
authors.forename: Esther M F
authors.initials: EM
authors.lastname: van Sluijs
authors.affiliation: Behaviour and Health Research Unit, University of Cambridge School of Clinical Medicine, Institute of Public Health, Cambridge, United Kingdom.
authors.forename: Theresa M
authors.initials: TM
authors.lastname: Marteau
authors.affiliation: Behavioural Science Group, University of Cambridge School of Clinical Medicine, Institute of Public Health, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Stephen
authors.initials: S
authors.lastname: Sutton
authors.affiliation: MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.
authors.forename: Stephen J
authors.identifier: http://orcid.org/0000-0003-2375-1440
authors.initials: SJ
authors.lastname: Sharp
authors.affiliation: MRC Epidemiology Unit, University of Cambridge School of Clinical Medicine, Cambridge, United Kingdom.|Primary Care Unit, University of Cambridge School of Clinical Medicine, Institute of Public Health, University of Cambridge, Cambridge, United Kingdom.
authors.forename: Simon J
authors.identifier: http://orcid.org/0000-0002-2157-4797
authors.initials: SJ
authors.lastname: Griffin
mesh_terms: D000328:Adult; D001007:Anxiety; D001835:Body Weight; D003924:Diabetes Mellitus, Type 2 / Q000235:genetics* / Q000517:prevention & control / Q000523:psychology*; D004032:Diet; D004739:England; D015444:Exercise; D005260:Female; D015438:Health Behavior; D058015:Health Communication; D006801:Humans; D008019:Life Style; D008297:Male; D008875:Middle Aged; D012306:Risk; D057566:Self Report