Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, New York.
The Lundquist Institute for Biomedical Innovation at Harbor-UCLA Medical Center, Torrance, California.
Cancer Epidemiol Biomarkers Prev. 2021 Sep;30(9):1753-1756. doi: 10.1158/1055-9965.EPI-21-0404. Epub 2021 Jun 29.
Results of observational studies of the association between dietary fat and risk of invasive breast cancer have been inconsistent. In the Women's Health Initiative dietary modification (DM) randomized trial designed to lower fat intake, the intervention was not associated with a statistically significant reduction of overall breast cancer risk. However, the DM association with risk of ductal carcinoma (DCIS) of the breast, a putative breast cancer precursor, has not been reported.
A total of 48,835 postmenopausal women, ages 50-79 years at enrollment, with no breast cancer history and ≥32% of total energy intake from fat, were randomly assigned either to a dietary intervention ( = 19,541) designed to reduce total fat intake to 20% of energy and to increase vegetable, fruit, and grain consumption, or to a comparison group ( = 29,294). Cox proportional hazards models were used to estimate HRs and 95% confidence intervals for the association between the intervention and DCIS risk.
During 18.7 years (median) cumulative follow-up, including intervention (∼8.7 years) and post-intervention phases (∼13.0 years), 817 DCIS cases were ascertained. No evidence of an association between the DM intervention and DCIS risk was observed overall, or by trial phase (intervention and post-intervention). Similarly, no associations were found in subgroups defined by potential risk factors for DCIS.
DM aiming to reduce fat intake was not associated with altered risk of DCIS.
These results do not provide evidence of an association between dietary fat reduction and the risk of DCIS among postmenopausal women.
观察性研究中关于脂肪摄入与侵袭性乳腺癌风险之间的关联结果不一致。在旨在降低脂肪摄入量的妇女健康倡议饮食干预（DM）随机试验中，干预与整体乳腺癌风险的统计学显著降低无关。然而，DM 与乳腺导管癌（DCIS）风险的关联，即乳腺癌的一个潜在前兆，尚未报道。
共有 48835 名绝经后妇女，入组时年龄为 50-79 岁，无乳腺癌病史，总能量摄入中脂肪占比≥32%，随机分配到饮食干预组（n=19541），设计为降低总脂肪摄入量至能量的 20%，并增加蔬菜、水果和谷物的摄入量，或比较组（n=29294）。使用 Cox 比例风险模型估计干预与 DCIS 风险之间的 HRs 和 95%置信区间。
在 18.7 年（中位数）的累积随访期间（包括干预期（约 8.7 年）和干预后期（约 13.0 年）），共确定了 817 例 DCIS 病例。总体上或按试验阶段（干预和干预后），均未发现 DM 干预与 DCIS 风险之间存在关联的证据。同样，在 DCIS 潜在风险因素定义的亚组中也未发现关联。
旨在减少脂肪摄入的 DM 与 DCIS 风险增加无关。
这些结果并未提供证据表明，在绝经后妇女中，减少膳食脂肪摄入与 DCIS 风险之间存在关联。
