American Journal of Epidemiology Advance Access originally published online on April 11, 2008
American Journal of Epidemiology 2008 167(12):1438-1445; doi:10.1093/aje/kwn080
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ORIGINAL CONTRIBUTIONS |
Insulin-like Growth Factor 1, Insulin-like Growth Factor-Binding Protein 3, and Testicular Germ-Cell Tumor Risk
1 Division of Cancer Epidemiology and Genetics, National Cancer Institute, Bethesda, MD
2 US Army Center for Health Promotion and Preventive Medicine, Washington, DC
3 Walter Reed Army Institute of Research, Forest Glen, MD
4 Keck School of Medicine, University of Southern California, Los Angeles, CA
Correspondence to Dr. Victoria M. Chia, Hormonal and Reproductive Epidemiology Branch, Division of Cancer Epidemiology and Genetics, National Cancer Institute, Executive Plaza South, Suite 550, 6120 Executive Boulevard, Rockville, MD 20892-7234 (e-mail: chiav{at}mail.nih.gov).
Received for publication November 6, 2007. Accepted for publication March 11, 2008.
Studies have consistently shown that taller men are at increased risk of testicular germ-cell tumors. Thus, it is plausible that factors associated with height may also influence risk of these tumors. The authors examined associations between testicular germ-cell tumor risk and circulating concentrations of insulin-like growth factor 1 (IGF-1) and insulin-like growth factor-binding protein 3 (IGFBP-3) among 517 cases and 790 controls from the US Servicemen's Testicular Tumor Environmental and Endocrine Determinants (STEED) Study (2002–2005). Odds ratios and 95% confidence intervals were estimated using logistic regression models, adjusting for age, race/ethnicity, height, and body mass index. All tests of significance were two-sided. Overall, there were no associations between IGF-1 or IGFBP-3 concentrations and risk of testicular germ-cell tumors (p > 0.05). However, when cases were separated by histologic type, there was a suggestion of a reduction in seminoma risk associated with the highest concentrations of IGF-1 as compared with the lowest concentrations (odds ratio = 0.66, 95% confidence interval: 0.40, 1.09). Although there were no overall associations with insulin-like growth factor, contrary to expectation, there was a suggestion that IGF-1 concentrations may be inversely associated with risk of seminoma.
hormones; insulin-like growth factor binding protein 3; insulin-like growth factor I; testicular neoplasms
Abbreviations: IGF, insulin-like growth factor; IGFBP-3, insulin-like growth factor-binding protein 3; STEED, US Servicemen's Testicular Tumor Environmental and Endocrine Determinants