title: Associations of plasma C-peptide and IGFBP-1 levels with risk of colorectal adenoma in a multiethnic population.
abstract: BACKGROUND
  Circulating levels of insulin and insulin-like growth factor (IGF) hormones have been associated with colorectal cancer risk, but few studies have examined their associations with colorectal adenoma.
  
  
  METHODS
  We measured plasma C-peptide, a marker of insulin secretion, and IGF hormones in a case-control study of 554 pathologically confirmed, first-time adenoma cases and 786 controls with normal endoscopy among Caucasians, Japanese, and Native Hawaiians in Hawaii.
  
  
  RESULTS
  High plasma levels of C-peptide were statistically significantly associated with risk of colorectal adenoma [multivariate odds ratio (95% confidence interval) for increasing quartiles: 1.0, 0.91 (0.65-1.27), 1.21 (0.86-1.71), and 1.79 (1.23-2.60); P(trend) = 0.0002]. We also observed a statistically significant inverse association between levels of plasma IGF binding protein-1 (IGFBP-1) and adenoma risk [1.0, 0.97 (0.70-1.34), 0.82 (0.58-1.15), and 0.47 (0.32-0.70); P(trend) <0.0001]. These associations remain significant after adjusting for each other and were not confounded by known risk factors. IGF-I, IGFBP-3, body mass index, and waist or hip circumference were not independently associated with adenoma risk.
  
  
  CONCLUSIONS
  These results provide evidence for an association of insulin and IGFBP-1 levels with colorectal adenoma.
  
  
  CONCLUSIONS
  This study suggests that hyperinsulinemia and IGF hormones may act as etiologic factors in colorectal carcinogenesis, as early as during adenoma formation.
authors.affiliation: Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, HI 96813, USA. Loic@crch.hawaii.edu
authors.forename: Loïc
authors.initials: L
authors.lastname: Le Marchand
authors.forename: Hansong
authors.initials: H
authors.lastname: Wang
authors.forename: Sabina
authors.initials: S
authors.lastname: Rinaldi
authors.forename: Rudolf
authors.initials: R
authors.lastname: Kaaks
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Vogt
authors.forename: Lance
authors.initials: L
authors.lastname: Yokochi
authors.forename: Robert
authors.initials: R
authors.lastname: Decker
mesh_terms: D000236:Adenoma / Q000097:blood* / Q000453:epidemiology / Q000208:ethnology; D000368:Aged; D044466:Asian People; D015992:Body Mass Index; D002096:C-Peptide / Q000097:blood*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000097:blood* / Q000453:epidemiology / Q000208:ethnology; D005006:Ethnicity; D005260:Female; D006254:Hawaii / Q000453:epidemiology; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood; D018970:Insulin-Like Growth Factor Binding Protein 1 / Q000097:blood*; D007564:Japan / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D044465:White People
chemical_list: D002096:C-Peptide; D018970:Insulin-Like Growth Factor Binding Protein 1