Serum concentrations of insulin-like growth factor and insulin-like growth factor binding protein 3 and recurrent colorectal adenomas.
Insulin-like growth factor I (IGF-I) and its primary binding protein, IGFBP-3, have been associated with colorectal cancer incidence in prior epidemiologic studies. High concentrations of IGF-I generally result in increasing risk and high concentrations of IGFBP-3 in decreasing risk. Only one prior study of IGF-I and IGFBP-3 and adenoma recurrence has been reported. We assayed fasting serum from 375 subjects with and 375 subjects without a recurrent adenoma during the course of the Polyp Prevention Trial to determine baseline concentrations of IGF-I and IGFBP-3. To estimate relative risk of adenoma recurrence over the course of 4 years of follow-up for each of these serum measures, we calculated odds ratios (OR) and 95% confidence intervals (CI) using multivariable logistic regression models adjusting for age, gender, body mass index, intervention group, aspirin, smoking, ethnicity, and education. For both IGF-I and IGFBP-3, we found trends indicating decreased risk for subjects in the high compared with the low quartile (for IGF-I: OR, 0.65; 95% CI 0.41-1.01; for IGFBP-3: OR, 0.66; 95% CI, 0.42-1.05). The associations were even greater for advanced adenomas (for IGF-I: OR, 0.51; 95% CI, 0.21-1.29; for IGFBP-3: OR, 0.32; 95% CI, 0.13-0.82). These results showed an unexpected null association, or even the suggestion of a reduction in risk for recurrent adenoma, with not just high IGFBP-3 concentration but also with high levels of IGF-I. Why IGF-I would decrease risk of recurrent adenoma (as distinct from incident adenoma or colorectal cancer) is not clear.
Division of Epidemiology and Community Health, University of Minnesota, 1300 South Second Street, Suite 300, Minneapolis, MN 55454, USA. flood009@umn.edu
Andrew
A
Flood
Volker
V
Mai
Ruth
R
Pfeiffer
Lisa
L
Kahle
Clifford J
CJ
Rosen
Elaine
E
Lanza
Arthur
A
Schatzkin
D000236:Adenoma / Q000097:blood* / Q000473:pathology; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000097:blood* / Q000473:pathology; D005260:Female; D006801:Humans; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000097:blood* / Q000473:pathology
D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I