Stoll B A
Oncology Department, St. Thomas' Hospital, London, UK.
Breast Cancer Res Treat. 1998 Jun;49(3):187-93. doi: 10.1023/a:1006003110909.
The typical high fat, low fibre diet of the industrialised West, particularly when associated with inadequate exercise, is likely to advance the onset of puberty. This will manifest in girls as an earlier menarche, earlier onset of breast development, and an earlier growth spurt. Both earlier menarche and adult tallness are markers of increased risk to breast cancer. Earlier menarche in the West is usually associated with earlier onset of hyperinsulinaemia, and multiple case-control studies report that hyperinsulinaemia too is a marker of increased breast cancer risk. Although the Western diet is linked both to earlier menarche and also to earlier hyperinsulinaemia, the mechanism involved is not necessarily the same. While menarche is likely to be triggered by a threshold level of fatness, manifestation of insulin resistance is genetically-determined and strongly influenced by the fatty acid profile of the diet. The putative mechanisms by which they influence mammary carcinogenesis also differ. Early menarche is reported to be associated with a raised oestradiol level persisting into early adult life. On the other hand, hyperinsulinaemia is commonly associated with abnormal aromatase activity in the ovaries. In addition, the concomitant increase in bioactive levels of insulin-like growth factor-I may synergise with oestrogen in stimulating proliferative activity in mammary epithelium. Dietary modification and exercise regimens are proposed in families at high risk to breast cancer. The measures have been shown to reduce insulin levels in both children and adults, and serial monitoring of insulin and sex steroid levels could be used to detect a metabolic-endocrine effect.
西方工业化国家典型的高脂肪、低纤维饮食，尤其是与缺乏运动相关时，可能会促使青春期提前到来。这在女孩身上表现为月经初潮提前、乳房发育开始时间提前以及生长突增提前。月经初潮提前和成年后身高较高都是患乳腺癌风险增加的标志。西方月经初潮提前通常与高胰岛素血症发病提前有关，多项病例对照研究报告称，高胰岛素血症也是患乳腺癌风险增加的标志。虽然西方饮食与月经初潮提前和高胰岛素血症发病提前都有关联，但其中涉及的机制不一定相同。月经初潮可能由一定程度的肥胖引发，而胰岛素抵抗的表现则由基因决定，并受饮食中脂肪酸构成的强烈影响。它们影响乳腺癌发生的假定机制也有所不同。据报道，月经初潮提前与成年早期持续存在的雌二醇水平升高有关。另一方面，高胰岛素血症通常与卵巢中芳香化酶活性异常有关。此外，胰岛素样生长因子 -I生物活性水平的相应增加可能与雌激素协同作用，刺激乳腺上皮的增殖活动。对于乳腺癌高危家庭，建议进行饮食调整和运动方案。这些措施已被证明可降低儿童和成人的胰岛素水平，对胰岛素和性类固醇水平进行连续监测可用于检测代谢 - 内分泌效应。
