Insulin-like growth factors and risk of benign prostatic hyperplasia

BACKGROUND. Insulin-like growth factors (IGFs) have potent mitogenic and antiapoptotic effects on prostate tissue, whereas IGF binding proteins (IGFBI's) inhibit growth of prostatic tissue. The IGF axis has been implicated in prostate cancer risk, but its role in benign prostatic hyperplasia (BPH) is unclear. METHODS. Plasma levels of IGF-I, IGF II, IGFBP-1, and IGFBP-3 were determined from the fasting bloods of 206 BPH cases admitted for treatment and 306 randomly selected population controls in Shanghai, China. RESULTS. Relative to the lowest tertile, men in the highest tertile of IGF-I levels had a significantly elevated risk of BPH (odds ratio [OR]=2.80, 95% confidence interval [95%, CI] =1.60-4.92; P-trend < 0.001). Results for IGF-I were more pronounced after adjustment for serum androgens. In contrast, men in the highest IGFBP-3 tertile had a significantly reduced risk (OR=0.40; 95% CI=0.23-0.69; P-trend < 0.001). No associations of BPH with IGF-II and IGFBP-1 were observed. CONCLUSION. As has been previously observed for prostate cancer, we found that IGF-I and IGFBP-3 are associated with BPH risk in China. Further investigation is needed to elucidate the role of the IGF axis in BPH etiology.