title: Food reinforcement and delay discounting in zBMI-discordant siblings.
abstract: OBJECTIVE
  The interaction of food reinforcement and the inability to delay gratification are related to adult energy intake and obesity. This study was designed to test the association of sibling pair differences in relative reinforcing efficacy of food and delay discounting on sibling pair differences in zBMI scores of same-gender zBMI-discordant siblings.
  
  
  METHODS
  We tested main and interactive relationships between delay discounting and relative reinforcing efficacy of food on zBMI discordance in 14 zBMI-discordant biological sibling pairs (6 female pairs) using a discordant sibling study design.
  
  
  RESULTS
  Sibling pair differences in relative reinforcing efficacy of food were associated with sibling pair differences in zBMI (p= 0.046); this effect was moderated by delay discounting (p <0.002). Sibling pairs with greater differences in relative reinforcing efficacy and delay discounting had greater differences in zBMI.
  
  
  CONCLUSIONS
  The combination of greater sibling pair differences in delay discounting and relative reinforcing efficacy is associated with greater discordance in zBMI in adolescent sibling pairs.
authors.affiliation: Department of Pediatrics, University at Buffalo, Buffalo, NY 14221, United States. Electronic address: denise.feda@waldenu.edu.
authors.forename: Denise M
authors.initials: DM
authors.lastname: Feda
authors.affiliation: USDA-ARS-NPA Grand Forks Human Nutrition Research Center, Grand Forks, ND, United States.
authors.forename: James N
authors.initials: JN
authors.lastname: Roemmich
authors.affiliation: Department of Pediatrics, University at Buffalo, Buffalo, NY 14221, United States.
authors.forename: April
authors.initials: A
authors.lastname: Roberts
authors.affiliation: Department of Pediatrics, University at Buffalo, Buffalo, NY 14221, United States.
authors.forename: Leonard H
authors.initials: LH
authors.lastname: Epstein
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002755:Choice Behavior; D065786:Delay Discounting; D004435:Eating / Q000523:psychology*; D002149:Energy Intake; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D016014:Linear Models; D008297:Male; D009765:Obesity / Q000523:psychology; D012054:Reinforcement, Psychology; D035781:Siblings
keywords: Delay discounting; Overweight; Relative reinforcing efficacy; Sibling