Larsson Susanna C, Bergkvist Leif, Wolk Alicja
The National Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden.
Am J Clin Nutr. 2009 Sep;90(3):556-60. doi: 10.3945/ajcn.2009.27480. Epub 2009 Jun 2.
Studies in animals and in vitro suggest that conjugated linoleic acids (CLAs), a group of fatty acids found mainly in dairy products and in the meat of ruminants, have protective effects against mammary carcinogenesis. However, findings from epidemiologic studies on CLA intake in relation to breast cancer risk are sparse and inconsistent.
The objective was to examine prospectively the association between CLA intake and the incidence of invasive breast cancer in the Swedish Mammography Cohort.
In 1987-1990, 61,433 cancer-free women completed a food-frequency questionnaire from which we estimated each woman's CLA intake. Cox proportional hazards models were used to estimate relative risks, adjusted for breast cancer risk factors.
During a mean follow-up of 17.4 y, 2952 incident cases of breast cancer were ascertained. In multivariate analyses, no significant association was observed between dietary CLA intake and risk of breast cancer, overall or by estrogen receptor (ER) and progesterone receptor (PR) status. The multivariate relative risks (95% CI) for the highest quintile of CLA intake (> or =155.7 mg/d) compared with the lowest quintile (<78.1 mg/d) were 1.04 (0.92, 1.17) for overall breast cancer, 1.09 (0.90, 1.31) for ER+/PR+ tumors, 1.09 (0.78, 1.53) for ER+/PR- tumors, and 0.84 (0.57, 1.24) for ER-/PR- tumors.
The results provide no evidence of a protective effect of CLA against breast cancer development in women.
动物实验和体外研究表明，共轭亚油酸（CLA）是一组主要存在于乳制品和反刍动物肉类中的脂肪酸，对乳腺癌发生具有保护作用。然而，关于CLA摄入量与乳腺癌风险关系的流行病学研究结果稀少且不一致。
前瞻性研究瑞典乳腺X线摄影队列中CLA摄入量与浸润性乳腺癌发病率之间的关联。
1987年至1990年期间，61433名未患癌症的女性完成了一份食物频率问卷，据此我们估算了每位女性的CLA摄入量。采用Cox比例风险模型估算相对风险，并对乳腺癌风险因素进行了校正。
在平均17.4年的随访期内，共确诊2952例乳腺癌病例。多因素分析显示，总体上或按雌激素受体（ER）和孕激素受体（PR）状态分类，膳食CLA摄入量与乳腺癌风险之间均未观察到显著关联。CLA摄入量最高五分位数组（≥155.7毫克/天）与最低五分位数组（<78.1毫克/天）相比，总体乳腺癌的多因素相对风险（95%CI）为1.04（0.92，1.17），ER+/PR+肿瘤为1.09（0.90，1.31），ER+/PR-肿瘤为1.09（0.78，1.53），ER-/PR-肿瘤为0.84（0.57，1.24）。
结果未提供CLA对女性乳腺癌发生具有保护作用的证据。
