Objective: Recent studies have suggested that a relationship between adiponectin and sex hormone, prolactin, and insulin-like growth factor levels could be important for breast cancer risk and insulin sensitivity. Therefore, we assessed the relationship of adiponectin with plasma concentrations of estrone; estradiol; estrone sulfate; testosterone; androstenedione; dehydroepiandrosterone (DHEA); dehydroepiandrosterone sulfate (DHEAS); sex hormone binding globulin (SHBG); prolactin; insulin-like growth factor (IGF-1); its binding protein, IGF binding protein 3 (IGFBP-3); c-peptide; and IGF binding protein 1 (IGFBP-1) among 360 postmenopausal women not taking postmenopausal hormones from the Nurses' Health Study.
Research methods and procedures: Multivariate models were adjusted for physical activity, alcohol consumption, age at blood draw, age at first birth/parity, fasting status, and time of day of blood draw; a separate model was additionally adjusted for BMI at blood draw.
Results: Estrogens were inversely associated with adiponectin levels; however, except for free estradiol, these associations were substantially attenuated after adjustment for BMI. Free estradiol levels were 27% lower among women in the top vs. bottom quartile of adiponectin levels. No consistent associations were observed for the androgens, prolactin, IGF-1, and IGFBP-3. However, SHBG, c-peptide, and IGFBP-1 were strongly and independently associated with adiponectin levels (r = 0.29, -0.30, 0.24, respectively).
Conclusion: With the exceptions of SHBG, c-peptide, and IGFBP-1, the studied analytes were modestly associated with adiponectin and the associations were, in large part, mediated by body fat.