Nagata C, Shimizu H, Takami R, Hayashi M, Takeda N, Yasuda K
Departments of Public Health, Gifu University School of Medicine, Gifu 500-8705, Japan.
Jpn J Cancer Res. 2000 Sep;91(9):948-53. doi: 10.1111/j.1349-7006.2000.tb01039.x.
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, was obtained by self-administered health questionnaire including a validated semiquantitative food frequency questionnaire. Body mass index (BMI) was significantly correlated with the ratio of estradiol to SHBG (Spearman r = 0.30, P = 0.0004), fasting plasma insulin (r = 0.45) and HOMA-R (r = 0.43, P = 0.0001) after controlling for age. The correlations were still significant between BMI and estradiol / SHBG ratio (r = 0.21, P = 0.047) after controlling for fasting plasma insulin and between BMI and fasting plasma insulin (r = 0.40, P = 0. 0001) as well as HOMA-R (r = 0.38, P = 0.0003) 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.
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风险因素的一个介导因素。另一方面，一些（但并非全部）众所周知的乳腺癌风险因素与血清雌激素浓度有关。我们评估了88名绝经后日本女性中潜在乳腺癌风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）之间的关系。我们还研究了胰岛素抵抗是否能解释乳腺癌风险因素与血清雌二醇和性激素结合球蛋白（SHBG）之间的关联。通过自我管理的健康问卷，包括经过验证的半定量食物频率问卷，获取了潜在乳腺癌风险因素的信息，如人口统计学特征、吸烟和饮酒习惯、饮食、运动、月经和生殖因素等。在控制年龄后，体重指数（BMI）与雌二醇与SHBG的比值（Spearman相关系数r = 0.30，P = 0.0004）、空腹血浆胰岛素（r = 0.45）和HOMA-R（r = 0.43，P = 0.0001）显著相关。在控制空腹血浆胰岛素后，BMI与雌二醇/SHBG比值之间的相关性仍然显著（r = 0.21，P = 0.047）；在控制雌二醇/SHBG比值后，BMI与空腹血浆胰岛素（r = 0.40，P = 0.0001）以及HOMA-R（r = 0.38，P = 0.0003）之间的相关性也仍然显著。BMI对乳腺癌风险的影响有可能是由胰岛素抵抗和雌激素代谢共同介导的。
