La Vecchia C, Decarli A, di Pietro S, Franceschi S, Negri E, Parazzini F
Eur J Cancer Clin Oncol. 1985 Apr;21(4):417-22. doi: 10.1016/0277-5379(85)90030-6.
The relationship between menstrual cycle patterns and the risk of breast disease was evaluated using data from a hospital-based case-control study of 288 women with benign breast disease (203 chronic cystic diseases and 85 benign tumours), 317 with breast cancer and 602 age-matched controls with a spectrum of acute conditions unrelated to any of the established or potential risk factors for breast disease. A lifelong irregular menstrual pattern [defined as frequent occurrence of menstrual-like episodes of bleeding less than 21 or more than 35 days apart) was negatively associated with the risk of benign breast lesions (relative risk, RR = 0.6, with 95% confidence interval = 0.4-1.0) and of breast cancer (RR = 0.4, with 95% confidence interval = 0.3-0.8]. This inverse association could not be explained by any of the identified potential confounding factors, including the major risk factors for breast disease. The findings of this study, showing that a lifelong history of irregular (and hence more likely anovular) cycles was less frequent among women with benign and malignant breast diseases, support the hypothesis that frequent ovular cycles might be more carcinogenic than anovular ones.
利用一项基于医院的病例对照研究的数据，评估了月经周期模式与乳腺疾病风险之间的关系。该研究纳入了288例患有良性乳腺疾病的女性（203例慢性囊性疾病和85例良性肿瘤）、317例乳腺癌患者以及602例年龄匹配的对照者，这些对照者患有一系列与乳腺疾病的任何既定或潜在风险因素无关的急性疾病。终生月经模式不规律（定义为月经样出血发作频繁，间隔时间少于21天或超过35天）与良性乳腺病变风险（相对风险，RR = 0.6，95%置信区间 = 0.4 - 1.0）和乳腺癌风险（RR = 0.4，95%置信区间 = 0.3 - 0.8）呈负相关。这种反向关联无法用任何已确定的潜在混杂因素来解释，包括乳腺疾病的主要风险因素。这项研究的结果表明，在患有良性和恶性乳腺疾病的女性中，终生不规律（因此更可能无排卵）周期的病史较少，这支持了频繁排卵周期可能比无排卵周期更具致癌性的假设。
