High circulating insulin-like growth factor-I (IGF-I) concentrations have been associated with increased risk for prostate cancer in several prospective epidemiological studies. In this study, we investigate the association between circulating IGF-I concentration and risk of prostate cancer over the long term in the European Prospective Investigation into Cancer and Nutrition (EPIC) study.In a nested case-control design, 1,542 incident prostate cancer cases from eight European countries were individually matched to 1,542 controls by study center, age at recruitment, duration of follow-up, time of day, and duration of fasting at blood collection. Conditional logistic regression models were used to calculate risk for prostate cancer associated with IGF-I concentration, overall and by various subgroups.Circulating IGF-I concentration was associated with a significant increased risk for prostate cancer [OR for highest vs. lowest quartile, 1.69; 95% confidence interval (CI), 1.35-2.13; P(trend) = 0.0002]. This positive association did not differ according to duration of follow-up [ORs for highest vs. lowest quartile were 2.01 (1.35-2.99), 1.37 (0.94-2.00), and 1.80 (1.17-2.77) for cancers diagnosed <4, 4-7, and >7 years after blood collection, respectively (P(heterogeneity) = 0.77)] or by stage, grade, and age at diagnosis or age at blood collection (all subgroups P(heterogeneity) >0.05).In this European population, high circulating IGF-I concentration is positively associated with risk for prostate cancer over the short and long term.As IGF-I is the only potentially modifiable risk factor so far identified, research into the effects of reducing circulating IGF-I levels on subsequent prostate cancer risk is warranted.

Original publication

DOI

10.1158/1055-9965.epi-12-0481-t

Type

Journal article

Journal

Cancer epidemiology, biomarkers & prevention : a publication of the American Association for Cancer Research, cosponsored by the American Society of Preventive Oncology

Publication Date

09/2012

Volume

21

Pages

1531 - 1541

Addresses

Cancer Epidemiology Unit, Nuffield Department of Clinical Medicine, University of Oxford, Oxford, United Kingdom. alison.price@ceu.ox.ac.uk

Keywords

Humans, Prostatic Neoplasms, Insulin-Like Growth Factor I, Insulin-Like Growth Factor Binding Protein 3, Logistic Models, Risk, Case-Control Studies, Prospective Studies, Aged, Middle Aged, Male