Insulin-like growth factor-1 and breast cancer risk in postmenopausal African-American women

We explored the relationship between insulin-like growth factor-1 (IGF-1) c oncentrations and breast cancer risk. Also, we examined whether obesity, se x hormone-binding globulin (SHBG), and estradiol influenced IGF-1 concentra tions. A pilot study of 60 postmenopausal African-American women (30 cases and 30 controls was used. Plasma concentrations of IGF-1 were higher among the cases, as compared to the controls. A negative trend was seen for plasm a concentrations of IGF-1 and TNM (tumor-node-metastasis) stage and IGF-1 a nd body mass index. IGF-1 was found to be associated negatively with SHBG. After adjustment, plasma concentrations of IGF-1 remained significantly and positively associated with breast cancer risk (odds ratio, 1.183; 95% conf idence interval, 1.167-1.201). No significant associations for breast cance r risk were observed for estradiol, SHBG, and body mass index. Further rese arch with a larger sample is needed to clarify the relationships between ob esity and IGF-1 concentrations to breast cancer risk in this population.