Plasma Insulin-Like Growth Factor-I, Insulin-Like Growth Factor-Binding Proteins, and Prostate Cancer Risk: a Prospective Study

• Published in: Journal of the National Cancer Institute
• Main Authors: Stattin, Pär, Bylund, Annika, Rinaldi, Sabina, Biessy, Carine, Déchaud, Henri, Stenman, Ulf-Håkan, Egevad, Lars, Riboli, Elio, Hallmans, Göran, Kaaks, Rudolf
• Format: Text
• Language: English
• Published: Oxford University Press 2000
• Subjects: ARTICLES; Northern Sweden
• Online Access: http://jnci.oxfordjournals.org/cgi/content/short/92/23/1910; https://doi.org/10.1093/jnci/92.23.1910

Background: Recent studies have suggested that men with elevated plasma levels of insulin-like growth factor-I (IGF-I) may have an increased risk of prostate cancer. Furthermore, IGF-binding proteins (IGFBPs) and insulin can modulate the activity of IGF-I. In this study, we sought to determine the role of IGF-I as well as IGFBPs-1, -2, and -3 and insulin as possible etiologic factors for prostate cancer. Methods: We conducted a nested case–control study within the Northern Sweden Health and Disease Cohort Study. We measured levels of IGF-I, IGFBP-1, IGFBP-2, IGFBP-3, and insulin in plasma samples from 149 men who had a diagnosis of prostate cancer between 1 month and 10 years after blood collection and among 298 control men. All statistical tests are two-sided. Results: Case subjects had statistically significantly higher mean levels of IGF-I than control subjects (229 ng/mL; 95% confidence interval [CI] = 218–240 ng/mL] versus 214 ng/mL [95% CI = 208–221 ng/mL]; P = .02) and IGFBP-3 (2611 ng/mL [95% CI = 2518–2704 ng/mL] versus 2498 ng/mL [95% CI = 2437–2560 ng/mL]; P = .04). Conditional logistic regression analyses showed increases in prostate cancer risk with rising levels of IGF-I ( P for trend = .02) and IGFBP-3 ( P for trend = .03). In case subjects younger than 59 years at the time of blood collection, the risk associated with increased IGF-I was higher ( P for trend = .01), whereas the risk associated with increased IGFBP-3 was lower ( P for trend = .44) than the corresponding risks in the full cohort. Prostate cancer risk was not associated with levels of IGFBP-1, IGFBP-2, or insulin. Conclusions: Prostate cancer risk is increased in men with elevated plasma IGF-I. This association was particularly strong in younger men in this study, suggesting that circulating IGF-I may be specifically involved in the early pathogenesis of prostate cancer.