title: Polygenic risk predicts obesity in both white and black young adults.
abstract: OBJECTIVE
  To test transethnic replication of a genetic risk score for obesity in white and black young adults using a national sample with longitudinal data.
  
  
  METHODS
  A prospective longitudinal study using the National Longitudinal Study of Adolescent Health Sibling Pairs (n = 1,303). Obesity phenotypes were measured from anthropometric assessments when study members were aged 18-26 and again when they were 24-32. Genetic risk scores were computed based on published genome-wide association study discoveries for obesity. Analyses tested genetic associations with body-mass index (BMI), waist-height ratio, obesity, and change in BMI over time.
  
  
  RESULTS
  White and black young adults with higher genetic risk scores had higher BMI and waist-height ratio and were more likely to be obese compared to lower genetic risk age-peers. Sibling analyses revealed that the genetic risk score was predictive of BMI net of risk factors shared by siblings. In white young adults only, higher genetic risk predicted increased risk of becoming obese during the study period. In black young adults, genetic risk scores constructed using loci identified in European and African American samples had similar predictive power.
  
  
  CONCLUSIONS
  Cumulative information across the human genome can be used to characterize individual level risk for obesity. Measured genetic risk accounts for only a small amount of total variation in BMI among white and black young adults. Future research is needed to identify modifiable environmental exposures that amplify or mitigate genetic risk for elevated BMI.
authors.affiliation: Institute of Behavioral Science, University of Colorado Boulder, Boulder, CO, United States of America.
authors.forename: Benjamin W
authors.initials: BW
authors.lastname: Domingue
authors.affiliation: Center for the Study of Aging and Human Development, Duke University Medical Center, Durham, NC, United States of America.
authors.forename: Daniel W
authors.initials: DW
authors.lastname: Belsky
authors.affiliation: Sociology Department and the Carolina Population Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States of America.
authors.forename: Kathleen Mullan
authors.initials: KM
authors.lastname: Harris
authors.affiliation: Institute for Behavioral Genetics, University of Colorado Boulder, Boulder, CO, United States of America.
authors.forename: Andrew
authors.initials: A
authors.lastname: Smolen
authors.affiliation: Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO, United States of America.
authors.forename: Matthew B
authors.initials: MB
authors.lastname: McQueen
authors.affiliation: Institute of Behavioral Science, University of Colorado Boulder, Boulder, CO, United States of America.
authors.forename: Jason D
authors.initials: JD
authors.lastname: Boardman
mesh_terms: D000293:Adolescent; D000328:Adult; D044383:Black People / Q000235:genetics*; D015992:Body Mass Index; D055106:Genome-Wide Association Study; D006801:Humans; D008137:Longitudinal Studies; D009765:Obesity / Q000235:genetics* / Q000473:pathology; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D011446:Prospective Studies; D012801:Sibling Relations; D065927:Waist-Height Ratio; D044465:White People / Q000235:genetics*; D055815:Young Adult; D001741:Black or African American