title: Body mass, DRD4, physical activity, sedentary behavior, and family socioeconomic status: the add health study.
abstract: OBJECTIVE
  To investigate the joint role of the 48-base pair repeat polymorphism of the dopamine receptor 4 gene (DRD4) and environmental factors in body mass variation among an ethnically diverse sample of U.S. adolescents and young adults.
  
  
  METHODS
  Approximately 2600 adolescent and young adults in the National Longitudinal Study of Adolescent Health (Add Health) who provided DNA measures and measures of height and weight were included in the analysis. Mixed regression modeling was used to investigate the effects of the 7R/7R and any5R variants in the DRD4 gene simultaneously with the effects of physical activity (PA), sedentary behavior (SB), and family socioeconomic status (SES) on body mass variation. European Americans, African Americans, and Hispanic Americans were modeled separately.
  
  
  CONCLUSIONS
  Both the 7R/7R and any5R genotypes of the DRD4 gene were associated with age- and sex-specific BMI percentile score (BMI-P) based on the Centers for Disease Control and Prevention/National Center for Health Statistics 2000 reference curves among African Americans and only among African Americans (N = 413) 20 years old or younger. Neither genetic variants are associated with the BMI measure among white (N = 1386) and Hispanic-American (N = 331) adolescents. The presence of the 7R/7R genotype was associated with a reduction of 15.1 in BMI percentile (p = 0.005), and the presence of any5R was associated with an increase of 15.5 in BMI percentile (p = 0.003), after adjusting for PA, SB, and family SES. Neither PA nor SB as measured in Add Health is importantly associated with BMI-P, suggesting a complex relationship between body mass and PA/SB among adolescents and young adults. Family SES is negatively related to BMI-P in the European-American sample.
authors.affiliation: Carolina Population Center, University of North Carolina, Chapel Hill, NC 27599-3210, USA. guang_guo@unc.edu
authors.forename: Guang
authors.initials: G
authors.lastname: Guo
authors.forename: Kari E
authors.initials: KE
authors.lastname: North
authors.forename: Penny
authors.initials: P
authors.lastname: Gorden-Larsen
authors.forename: Cynthia M
authors.initials: CM
authors.lastname: Bulik
authors.forename: Seulki
authors.initials: S
authors.lastname: Choi
mesh_terms: D000293:Adolescent; D000328:Adult; D001835:Body Weight; D002648:Child; D005006:Ethnicity; D015444:Exercise / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007899:Leisure Activities; D008297:Male; D009657:North Carolina; D050638:Receptors, Dopamine D4 / Q000235:genetics*; D035781:Siblings; D012959:Socioeconomic Factors
chemical_list: C493599:DRD4 protein, human; D050638:Receptors, Dopamine D4