Alvin J. Siteman Cancer Center and Department of Surgery, Washington University School of Medicine, St. Louis, MO, USA.
Cancer Causes Control. 2011 Sep;22(9):1297-305. doi: 10.1007/s10552-011-9803-y. Epub 2011 Jul 12.
Exercise is a modifiable factor that is inversely related to risk for breast cancer. To determine if physical activity has a preventative effect on development of premalignant breast lesions, we examined the association between exercise and the incidence of proliferative benign breast disease.
In 1997, the Nurses' Health Study II cohort reported levels of physical activity during adolescence and adulthood using a validated recall instrument. We followed 40,318 participants free from benign breast disease (BBD) or cancer prospectively for four years and confirmed 232 proliferative benign breast lesions by centralized pathology review. Cox proportional hazards models estimated the age-adjusted and multivariable-adjusted relative risks for physical activity and proliferative benign breast disease.
We observed a significant inverse association for walking and incidence of BBD, risk was reduced by 9% per hour of walking (95% CI 0% to 17%), (p trend = 0.05). Despite a small number of cases, risk of columnar cell lesions also suggested an inverse association with strenuous activity (RR for 4 or more hours of strenuous activity per week = 0.62; 0.31-1.22 compared to < 1 h per week).
This study suggests that exercise may be inversely associated with the risk of developing proliferative benign breast disease, one of the earliest steps in the development of breast cancer.
运动是一个可改变的因素，与乳腺癌风险呈负相关。为了确定体力活动是否对良性乳腺病变的发展具有预防作用，我们研究了运动与增生性良性乳腺疾病的发病率之间的关系。
1997 年，护士健康研究 II 队列使用经过验证的回顾性仪器报告了青少年和成年期的体力活动水平。我们前瞻性地随访了 40318 名无良性乳腺疾病（BBD）或癌症的参与者，随访时间为 4 年，并通过集中病理审查确认了 232 例增生性良性乳腺病变。Cox 比例风险模型估计了体力活动和增生性良性乳腺疾病的年龄调整和多变量调整相对风险。
我们观察到步行与 BBD 的发病率呈显著负相关，步行每小时风险降低 9%（95%CI 0%至 17%），（趋势检验 p=0.05）。尽管病例数较少，但剧烈活动与柱状细胞病变的风险也呈负相关（每周 4 小时或更多剧烈活动的 RR=0.62；0.31-1.22 与每周<1 小时相比）。
这项研究表明，运动可能与增生性良性乳腺疾病的风险呈负相关，增生性良性乳腺疾病是乳腺癌发展的最早阶段之一。
