title: The Moderating Role of Insulin-Like Growth Factor 1 in the Relationship Between Cognitive and Aerobic Endurance Change.
abstract: BACKGROUND
  Improvements in cognition often accompany fitness improvements in older adults, and research suggests insulin-like growth factor 1 (IGF-1) may influence this association. No prior work has examined this in mild cognitive impairment (MCI). We predicted that IGF-1 would moderate the relationship between cognition and aerobic endurance improvement, such that greater baseline IGF-1 would accompany a stronger relationship between cognition and aerobic endurance change.
  
  
  METHODS
  Twenty-seven individuals with MCI completed assessments of aerobic endurance (2-minute step test [2MST]) and global cognition (Modified Mini-Mental State [3MS]) before and after a 6-month period of twice-weekly exercise. Serum IGF-1 levels were assessed at baseline via fasted blood draw. The Johnson-Neyman technique determined whether baseline IGF-1 levels moderated the relationship between changes in aerobic endurance (Δ2MST) and cognition (Δ3MS).
  
  
  RESULTS
  A significant interaction was found; however, Δ2MST was inversely associated with Δ3MS in individuals with above-average serum IGF-1 levels; this relationship was strengthened as IGF-1 increased and was not seen when IGF-1 was below average.
  
  
  CONCLUSIONS
  The relationship between cognitive and aerobic endurance change varies as a function of IGF-1 in persons with MCI. Additional work is needed to clarify the mechanisms of these findings.
authors.affiliation: 1 Department of Psychological Sciences, Kent State University, Kent, OH, USA.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Anderson
authors.affiliation: 1 Department of Psychological Sciences, Kent State University, Kent, OH, USA.
authors.forename: Dayana
authors.initials: D
authors.lastname: Calvo
authors.affiliation: 2 Exercise Physiology Laboratory, Kent State University, Kent, OH, USA.
authors.forename: Ellen
authors.initials: E
authors.lastname: Glickman
authors.affiliation: 1 Department of Psychological Sciences, Kent State University, Kent, OH, USA.
authors.forename: John
authors.initials: J
authors.lastname: Gunstad
authors.affiliation: 1 Department of Psychological Sciences, Kent State University, Kent, OH, USA.
authors.forename: Mary Beth
authors.initials: MB
authors.lastname: Spitznagel
mesh_terms: D000328:Adult; D000368:Aged; D003071:Cognition / Q000502:physiology*; D060825:Cognitive Dysfunction / Q000235:genetics* / Q000503:physiopathology* / Q000523:psychology; D015444:Exercise / Q000502:physiology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism / Q000502:physiology*; D008297:Male; D010807:Physical Endurance
chemical_list: D007334:Insulin-Like Growth Factor I
keywords: aging; cognition; exercise; insulin-like growth factor 1; mild cognitive impairment