Concentrations of estrogens and IGFs in umbilical cord blood plasma: a comparison among Caucasian, Hispanic, and Asian-American females.

It has been hypothesized that exposure to elevated levels of estrogens and IGFs before birth may increase breast cancer risk in female offspring. We examined whether the concentrations of estrone, E2, IGF-I, IGF-II, and IGF-binding protein-1 (IGFBP-1), -2, and -3 in umbilical cord blood plasma differed in female neonates of three racial/ethnic groups with contrasting breast cancer risk. The study included 57 Caucasian, 22 Hispanic, and 22 Asian-American subjects. Relative contribution of race/ethnicity to the analyte level variability was the largest for IGFBP-1 (P = 0.06). The only statistically significant (P < 0.05) mean difference was the lower IGFBP-3 levels in Asian than in Caucasian subjects. Adjusted mean levels of estrone and E2 for Asian subjects were 128% and 109% of the Caucasian means, respectively, whereas the Hispanic group showed lower means (85% and 84% of the Caucasian means). IGF-I, IGFBP-1, and IGFBP-3 showed lower adjusted means for both Hispanics and Asians compared with Caucasians. However, these differences were not statistically significant. In summary, we have shown that concentrations of estrogens, IGF-I, IGF-II, and IGFBPs are not different in cord blood samples from Caucasian, Hispanic, and Asian-American subjects. These data do not support a link between antenatal exposure to elevated levels of estrogens and IGFs and breast cancer.