Narita Saki, Inoue Manami, Saito Eiko, Abe Sarah K, Sawada Norie, Ishihara Junko, Iwasaki Motoki, Yamaji Taiki, Shimazu Taichi, Sasazuki Shizuka, Shibuya Kenji, Tsugane Shoichiro
Department of Global Health Policy, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 1130033, Japan.
AXA Department of Health and Human Security, Graduate School of Medicine, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 1130033, Japan.
Cancer Causes Control. 2017 Jun;28(6):569-578. doi: 10.1007/s10552-017-0881-3. Epub 2017 Mar 23.
Epidemiological studies have suggested a protective effect of dietary fiber intake on breast cancer risk while the results have been inconsistent. Our study aimed to investigate the association between dietary fiber intake and breast cancer risk and to explore whether this association is modified by reproductive factors and hormone receptor status of the tumor.
A total of 44,444 women aged 45 to 74 years from the Japan Public Health Center-based Prospective Study were included in analyses. Dietary intake assessment was performed using a validated 138-item food frequency questionnaire (FFQ). Hazard ratios (HRs) and 95% confidence intervals (CIs) for breast cancer incidence were calculated by multivariate Cox proportional hazards regression models.
During 624,423 person-years of follow-up period, 681 breast cancer cases were identified. After adjusting for major confounders for breast cancer risk, inverse trends were observed but statistically non-significant. Extremely high intake of fiber was associated with decreased risk of breast cancer but this should be interpreted with caution due to limited statistical power. In stratified analyses by menopausal and hormone receptor status, null associations were observed except for ER-PR- status.
Our findings suggest that extreme high fiber intake may be associated with decreased risk of breast cancer but the level of dietary fiber intake among Japanese population might not be sufficient to examine the association between dietary fiber intake and breast cancer risk.
流行病学研究表明膳食纤维摄入对乳腺癌风险具有保护作用，但其结果并不一致。我们的研究旨在调查膳食纤维摄入与乳腺癌风险之间的关联，并探讨这种关联是否会因生殖因素和肿瘤的激素受体状态而改变。
来自日本公共卫生中心前瞻性研究的44444名年龄在45至74岁之间的女性被纳入分析。使用经过验证的138项食物频率问卷（FFQ）进行饮食摄入评估。通过多变量Cox比例风险回归模型计算乳腺癌发病率的风险比（HRs）和95%置信区间（CIs）。
在624423人年的随访期内，共确诊681例乳腺癌病例。在调整了乳腺癌风险的主要混杂因素后，观察到呈负相关趋势，但在统计学上无显著意义。极高的纤维摄入量与降低乳腺癌风险相关，但由于统计效力有限，对此应谨慎解释。在按绝经和激素受体状态进行的分层分析中，除了雌激素受体（ER）-孕激素受体（PR）双阴性状态外，未观察到相关性。
我们的研究结果表明，极高的纤维摄入量可能与降低乳腺癌风险相关，但日本人群的膳食纤维摄入量水平可能不足以检验膳食纤维摄入与乳腺癌风险之间的关联。
