title: Higher C-peptide levels are associated with regional cortical thinning in 1093 cognitively normal subjects.
abstract: OBJECTIVE
  Recent studies have demonstrated an association between increased insulin secretion and cognitive impairment. However, there is no previous study that directly evaluates the association between increased insulin secretion and cortical thickness to our knowledge. Therefore, our aim was to evaluate the effect of hyperinsulinemia, as measured by C-peptide level, on cortical thickness in a large sample of cognitively normal individuals.
  
  
  METHODS
  Cortical thickness was measured in 1093 patients who visited the Samsung Medical Health Promotion Center and underwent brain magnetic resonance imaging (MRI) and a blood test to measure C-peptide concentration. Automated surface-based analyses of the MRI data were used to measure cortical thickness. C-peptide levels were divided into quartiles for comparison. Patients in the first to third quartiles were used as the reference category.
  
  
  RESULTS
  Patients in the highest quartile group (Q4) of C-peptide levels showed cortical thinning, predominantly in both medial temporal lobes, the right inferior temporal gyrus, both medial prefrontal lobes and the right superior parietal lobule, compared with the lower quartile groups (Q1-Q3) after controlling for age, gender, body mass index, history of hypertension, hyperlipidemia, previous stroke, cardiovascular disease and fasting glucose level.
  
  
  CONCLUSIONS
  A higher C-peptide level is associated with regional cortical thinning, even in cognitively normal individuals.
authors.affiliation: Department of Neurology, Inha University School of Medicine, Incheon, South Korea.
authors.forename: C W
authors.initials: CW
authors.lastname: Yoon
authors.forename: M
authors.initials: M
authors.lastname: Kang
authors.forename: H Y
authors.initials: HY
authors.lastname: Shin
authors.forename: S
authors.initials: S
authors.lastname: Jeon
authors.forename: J-J
authors.initials: JJ
authors.lastname: Yang
authors.forename: S T
authors.initials: ST
authors.lastname: Kim
authors.forename: Y
authors.initials: Y
authors.lastname: Noh
authors.forename: G H
authors.initials: GH
authors.lastname: Kim
authors.forename: H J
authors.initials: HJ
authors.lastname: Kim
authors.forename: Y J
authors.initials: YJ
authors.lastname: Kim
authors.forename: J-H
authors.initials: JH
authors.lastname: Kim
authors.forename: H
authors.initials: H
authors.lastname: Cho
authors.forename: B S
authors.initials: BS
authors.lastname: Ye
authors.forename: J M
authors.initials: JM
authors.lastname: Lee
authors.forename: S H
authors.initials: SH
authors.lastname: Choi
authors.forename: K
authors.initials: K
authors.lastname: Im
authors.forename: H-S
authors.initials: HS
authors.lastname: Moon
authors.forename: D L
authors.initials: DL
authors.lastname: Na
authors.forename: S W
authors.initials: SW
authors.lastname: Seo
mesh_terms: D000368:Aged; D002096:C-Peptide / Q000097:blood*; D002540:Cerebral Cortex / Q000473:pathology*; D005260:Female; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged
chemical_list: D002096:C-Peptide
keywords: C-peptide; cortical thinning; insulin