Suppr超能文献

低脂高碳水化合物饮食对乳房放射学特征的两年影响:一项随机试验的结果。加拿大饮食与乳腺癌预防研究组

Effects at two years of a low-fat, high-carbohydrate diet on radiologic features of the breast: results from a randomized trial. Canadian Diet and Breast Cancer Prevention Study Group.

作者信息

Boyd N F, Greenberg C, Lockwood G, Little L, Martin L, Byng J, Yaffe M, Tritchler D

机构信息

Division of Epidemiology and Statistics, Ontario Cancer Institute, Toronto, Canada.

出版信息

J Natl Cancer Inst. 1997 Apr 2;89(7):488-96. doi: 10.1093/jnci/89.7.488.

Abstract

BACKGROUND

The appearance of breast tissue on mammography varies according to its composition. Fat is radiolucent and appears dark on mammography, while stromal and epithelial tissue has greater optical density and appears light. Extensive areas of radiologically dense breast tissue seen on mammography are associated with an increased risk of breast cancer.

PURPOSE

The purpose of the present study was to determine whether the adoption of a low-fat, high-carbohydrate diet for 2 years would reduce breast density.

METHODS

Women with radiologic densities in more than 50% of the breast area on mammography were recruited and randomly allocated to an intervention group taught to reduce intake of dietary fat (mean, 21% of calories) and increase complex carbohydrate (mean, 61% of calories) or to a control group (mean, 32% of calories from fat and 50% of calories from carbohydrates). Mammographic images from 817 subjects were taken at baseline and compared with those taken 2 years after random allocation by use of a quantitative image analysis system, without knowledge of the dietary group of the subjects or of the sequence in which pairs of images had been taken. The effects of the intervention on the mammographic features of breast area, area of dense tissues in the breast, and the percent of the breast occupied by dense tissue were examined using t tests. Multiple regression was used to examine these effects while accounting for age at trial entry, weight change, and menopausal status.

RESULTS

After 2 years, the total area of the breast was reduced by an average of 233.7 mm2 (2.4%) (95% confidence interval [CI] = 106.9-360.6) in the intervention group compared with an average increase of 26.3 mm2 (0.3%) (95% CI = -108.0-160.5) in the control group (P = .01). The area of density was reduced by 374.4 mm2 (6.1%) (95% CI = 235.1-513.8) in the intervention group compared with an average of 127.7 mm2 (2.1%) (95% CI = 8.6-246.7) in the control group (P = .01). Weight loss was associated with a reduction in breast area. The effect of the intervention on breast area was only marginally statistically significant after weight change, menopausal status, and age at trial entry were taken into account (P = .06). Greater weight loss and becoming postmenopausal were associated with statistically significant reductions in the area of density on the mammographic image at 2 years (P = .04 and P<.001, respectively). Age at entry into the trial was marginally significant in the same direction (P = .06). The effect of the intervention on area of density remained statistically significant after controlling for weight loss, age at entry, and menopausal status (P = .03). The change in the percentage of dense tissue in the mammographic image was not significantly different between the two groups (P = .71).

CONCLUSIONS AND IMPLICATIONS

These results show that after 2 years, a low-fat, high-carbohydrate diet reduced the area of mammographic density, a radiographic feature of the breast that is a risk factor for breast cancer. Longer observation of a larger number of subjects will be required to determine whether these effects are associated with changes in risk of breast cancer.

摘要

背景

乳房X线摄影中乳房组织的外观因其组成成分而异。脂肪在X线下是透光的,在乳房X线摄影中呈暗色,而基质和上皮组织具有更高的光学密度,呈亮色。乳房X线摄影中可见的广泛放射致密乳房组织区域与乳腺癌风险增加相关。

目的

本研究的目的是确定采用低脂、高碳水化合物饮食2年是否会降低乳房密度。

方法

招募乳房X线摄影中乳房区域超过50%为放射致密的女性,并随机分配至干预组,指导其减少膳食脂肪摄入(平均占卡路里的21%)并增加复合碳水化合物摄入(平均占卡路里的61%),或分配至对照组(平均32%的卡路里来自脂肪,50%的卡路里来自碳水化合物)。在基线时对817名受试者进行乳房X线摄影,并在随机分组2年后再次进行摄影,使用定量图像分析系统进行比较,且不知道受试者的饮食组或图像拍摄顺序。使用t检验检查干预对乳房区域的乳房X线摄影特征、乳房致密组织面积以及致密组织占乳房的百分比的影响。在考虑试验入组时的年龄、体重变化和绝经状态的情况下,使用多元回归分析这些影响。

结果

2年后,干预组乳房总面积平均减少233.7 mm²(2.4%)(95%置信区间[CI]=106.9 - 360.6),而对照组平均增加26.3 mm²(0.3%)(95% CI = -108.0 - 160.5)(P = 0.01)。干预组致密组织面积减少374.4 mm²(6.1%)(95% CI = 235.1 - 513.8),而对照组平均减少127.7 mm²(2.1%)(95% CI = 8.6 - 246.7)(P = 0.01)。体重减轻与乳房面积减少相关。在考虑体重变化、绝经状态和试验入组时的年龄后,干预对乳房面积的影响仅具有边缘统计学意义(P = 0.06)。更大程度的体重减轻和进入绝经后状态与2年时乳房X线摄影图像上致密组织面积的统计学显著减少相关(分别为P = 0.04和P < 0.001)。试验入组时的年龄在相同方向上具有边缘显著性(P = 0.06)。在控制体重减轻、入组时的年龄和绝经状态后,干预对致密组织面积的影响仍具有统计学意义(P = 0.03)。两组乳房X线摄影图像中致密组织百分比的变化无显著差异(P = 0.71)。

结论与启示

这些结果表明,2年后,低脂、高碳水化合物饮食减少了乳房X线摄影致密面积,这是乳房的一种放射学特征,也是乳腺癌的一个风险因素。需要对更多受试者进行更长时间的观察,以确定这些影响是否与乳腺癌风险的变化相关。

文献AI研究员

20分钟写一篇综述,助力文献阅读效率提升50倍。

立即体验

用中文搜PubMed

大模型驱动的PubMed中文搜索引擎

马上搜索

文档翻译

学术文献翻译模型,支持多种主流文档格式。

立即体验