糖尿病与肥胖提高乳腺癌风险

    瑞典一项研究揭示，患有糖尿病或60岁以后肥胖显著升高乳腺癌患病风险。研究还表明，诊断乳腺癌时高血脂并不常见，而低血脂与乳腺癌风险升高有关。

　　研究者在2011年12月6-10日举行的圣安东尼奥乳腺癌大会上报告了上述研究结果。研究者还关注了癌症总体发病率，并发现使用某种糖尿病治疗药物与任意癌症发病率较低有关，而使用另外一种糖尿病治疗药物与该风险升高有关。

　　研究者评估了瑞典西南部一个拥有150万人口的地区的卫生保健数据，以对癌症风险有一个全面深入的了解。

　　“我们观察了每一个人，发现成年女性糖尿病和60岁及以上女性肥胖显著升高乳腺癌风险，” 瑞典兰德大学肿瘤学和癌症流行病学系教授Håkan Olsson博士说，“这对于想知道自身风险和可采取措施降低风险的女性来说是有价值的信息。

　　他和他的同事们评估了2724例患者罹患癌症前长达10年间的病例资料，以及20542例未曾罹患癌症的患者的病例资料。

　　他们发现女性60岁以后肥胖使乳腺癌风险升高55%。“与普通人群乳腺癌发病率稍低于10%相比，这一数值在肥胖女性中最高为15%，” Olsson说。

　　如果在被诊断为癌症前糖尿病病史已经达4年，女性糖尿病患者罹患乳腺癌的风险将升高37%。

　　血脂水平异常偏低的女性罹患乳腺癌的风险升高25%，而血脂水平高被揭示与乳腺癌风险较低有关。这种现象的背后机制尚不清楚，并且这一发现还有待其他基于人群研究的验证，Olsson说。

　　研究者还调查了瑞典全国药物处方登记资料，以探索各种癌症与应用甘精胰岛素和二甲双胍的关系。在这项研究中，研究者发现，此前已经被欧洲研究证明与癌症风险升高有关的甘精胰岛素几乎使任意癌症风险加倍；而二甲双胍与糖尿病患者癌症风险降低8%有关。

　　Olsson说，今后需要更多研究以阐明某种类型癌症风险升高的原因。在该研究中，使用上述药物且罹患乳腺癌的患者人数较少，因此不能得出它们与乳腺癌风险有关，他说。

相关文献：

Goodwin PJ, Stambolic V.Obesity and insulin resistance in breast cancer--chemoprevention strategies with a focus on metformin.Breast. 2011 Oct;20 Suppl 3:S31-5.

Pandey A, Forte V, Abdallah M, Alickaj A, Mahmud S, Asad S, McFarlane SI.Diabetes mellitus and the risk of cancer.Minerva Endocrinol. 2011 Sep;36(3):187-209.

La Vecchia C, Giordano SH, Hortobagyi GN, Chabner B.Overweight, obesity, diabetes, and risk of breast cancer: interlocking pieces of the puzzle.Oncologist. 2011;16(6):726-9.

Hemminki K, Li X, Sundquist J, Sundquist K.Obesity and familial obesity and risk of cancer. Eur J Cancer Prev. 2011 Sep;20(5):438-43.

英文相关报道：

SAN ANTONIO — Having diabetes or being obese after age 60 significantly increases the risk for developing breast cancer, a Swedish study has revealed. Data also showed that high blood lipids were less common in patients when diagnosed with breast cancer, while low blood lipids were associated with an increased risk.

Researchers of the study, reported at the 2011 CTRC-AACR San Antonio Breast Cancer Symposium, held Dec. 6-10, 2011, also looked at overall cancer incidence and discovered that use of one diabetes drug was associated with a lower rate of any cancer, while another was associated with an increased risk.

Researchers evaluated health care data from a region of 1.5 million people living in Southwestern Sweden to provide a comprehensive picture of cancer risk.

“We are looking at everybody, and we found that diabetes in adult women and obesity in women aged 60 and older significantly increased breast cancer risk,” said Håkan Olsson, M.D., professor in the departments of oncology and cancer epidemiology at Lund University. “This is useful information for women who want to know their risk and who can take steps to lower it.”

He and his colleagues examined records of 2,724 patients up to 10 years before they developed cancer and 20,542 patients who never developed the disease.

They found that obesity in women after age 60 increased risk for developing breast cancer by 55 percent. “At the most, 15 out of 100 obese women would get breast cancer compared with slightly less than 10 out of 100 in the general population,” Olsson said.
Women with diabetes had a 37 percent increased risk for developing breast cancer if their diabetes had been diagnosed up to four years before cancer was diagnosed.

Women with abnormally low levels of blood lipids (mostly cholesterol) had a 25 percent greater risk for developing breast cancer, while high levels of blood lipids appeared to be associated with a lower risk for breast cancer. The mechanisms behind these effects are unclear, and the finding needs to be replicated in a different population-based study, Olsson said.

Researchers also looked at the national drug prescription registry to examine the link between risk for all cancers and use of two diabetes drugs, glargine and metformin. In this study, investigators found that glargine use, which had been associated with increased cancer development in previous European studies, almost doubled the risk for development of any cancer, while metformin was linked to an 8 percent lower risk for cancer in patients with diabetes.

Olsson said more research is needed to clarify the specific cancers at increased risk. The number of patients in this study who developed breast cancer using these medications was too small to make any link to breast cancer risk, specifically, he said.

The study was funded by Sweden’s Southern Health Care Region.