Associations of plasma C-peptide and IGFBP-1 levels with risk of colorectal adenoma in a multiethnic population.
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.
Le Marchand
Loïc
L
Epidemiology Program, Cancer Research Center of Hawaii, University of Hawaii, Honolulu, HI 96813, USA. Loic@crch.hawaii.edu
Wang
Hansong
H
Rinaldi
Sabina
S
Kaaks
Rudolf
R
Vogt
Thomas M
TM
Yokochi
Lance
L
Decker
Robert
R
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
D002096:C-Peptide; D018970:Insulin-Like Growth Factor Binding Protein 1