Insulin resistance in relation to diet, lifestyle, and estrogen profile in Japanese women.

有一种假说认为高胰岛素血症或胰岛素抵抗可能是乳腺癌危险因素的中介。另一方面，一些但不是所有众所周知的乳腺癌危险因素都与血清雌激素浓度有关。我们评估了88名日本绝经后妇女的潜在乳腺癌危险因素与胰岛素抵抗指标、空腹血浆胰岛素浓度和稳态模型评估胰岛素抵抗（HOMA-R）的关系。我们还研究了胰岛素抵抗是否可以解释血清雌二醇和性激素结合球蛋白（SHBG）与乳腺癌危险因素的关联。通过自我管理的健康问卷（包括经验证的半定量食物频率问卷）获得潜在乳腺癌风险因素的信息，如人口特征、吸烟和饮酒习惯、饮食、运动、月经和生殖因素。在控制年龄后，身体质量指数（BMI）与雌二醇/ SHBG、空腹血浆胰岛素、HOMA-R有显著相关。在控制空腹血浆胰岛素后，BMI与雌二醇/SHBG比值的相关性仍然显著；在控制雌二醇/SHBG比值后，BMI与空腹血浆胰岛素及HOMA-R的相关性仍然显著。BMI对乳腺癌风险的影响可能是胰岛素抵抗和雌激素代谢共同介导的。

There is a hypothesis that hyperinsulinemia or insulin resistance may be a mediator for breast cancer risk factors. On the other hand, some but not all of the well-known risk factors of breast cancer have been associated with serum estrogen concentrations. We assessed the relationships of potential breast cancer risk factors to indicators of insulin resistance, fasting plasma insulin concentration and homeostasis model assessment insulin resistance (HOMA-R), in 88 postmenopausal Japanese women. We also examined whether insulin resistance would explain the association of breast cancer risk factors with serum estradiol and sex hormone-binding globulin (SHBG). Information on potential breast cancer risk factors such as demographic characteristics, smoking and drinking habits, diet, exercise, menstrual and reproductive factors were obtained by self-administered health questionnaire including validated semiquantitative food frequency questionnaire. Body mass index (BMI) was significantly correlated with the ratio of estradiol to SHBG, fasting plasma insulin, and HOMA-R after controlling for age. The correlations were still significant between BMI and estradiol/SHBG ratio after controlling for fasting plasma insulin and between BMI and fasting plasma insulin as well as HOMA-R after controlling for estradiol/SHBG ratio. There is a possibility that effect of BMI on breast cancer risk is mediated by both insulin resistance and estrogen metabolism.