Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tsukiji 5-1-1, Chuo-ku, Tokyo 104-0045, Japan.
Cancer Causes Control. 2010 Nov;21(11):1787-98. doi: 10.1007/s10552-010-9605-7. Epub 2010 Jul 4.
Physical activity may decrease breast cancer risk. However, it is unclear what intensity of exercise and during which life periods this effect on decreasing risk is efficiently expressed, and whether the associations differ by the estrogen-/progesterone- receptor (ER/PR) status of tumors. We investigated associations between age- and intensity-specific leisure-time physical activity and ER/PR-defined breast cancer risk.
We conducted a hospital-based case-control study in Nagano, Japan. Subjects were 405 cases newly diagnosed (>99% known ER/PR) from 2001 to 2005, who were age-/area-matched with 405 controls. Activity was assessed with a self-reported questionnaire which considered intensity level (moderate and/or strenuous) at different ages (at 12 and 20 years, and in the previous 5 years). Odds ratios (ORs) and 95% confidence intervals were calculated using logistic regression.
Strenuous but not moderate physical activity at age 12 was inversely associated with pre- and postmenopausal breast cancer risk across ER/PR subtypes [overall OR(≥ 5 days/week vs. none) = 0.24 (0.14-0.43)]. Moderate physical activity in the previous 5 years was significantly associated with a decrease in risk for postmenopausal ER + PR + tumors only [OR(≥ 1 day/week vs. none) = 0.35 (0.18-0.67)].
Strenuous activity in teens and moderate activity after menopause may contribute to a reduction in breast cancer risk.
身体活动可能降低乳腺癌风险。然而，目前尚不清楚何种运动强度和生命阶段的运动对降低风险的效果最佳，以及这种关联是否因肿瘤的雌激素/孕激素受体（ER/PR）状态而异。我们研究了年龄和强度特异性休闲时间身体活动与 ER/PR 定义的乳腺癌风险之间的关联。
我们在日本长野县进行了一项以医院为基础的病例对照研究。研究对象为 2001 年至 2005 年间新诊断的 405 例病例（99%以上已知 ER/PR），并按年龄/地区与 405 名对照相匹配。通过自我报告问卷评估活动情况，该问卷考虑了不同年龄（12 岁和 20 岁以及过去 5 年）的活动强度水平（适度和/或剧烈）。使用逻辑回归计算比值比（OR）和 95%置信区间。
12 岁时剧烈但非适度的体力活动与各 ER/PR 亚型的绝经前和绝经后乳腺癌风险呈负相关[总体 OR（每周≥ 5 天与无）= 0.24（0.14-0.43）]。过去 5 年内适度的体力活动仅与绝经后 ER+PR+肿瘤风险降低显著相关[OR（每周≥ 1 天与无）= 0.35（0.18-0.67）]。
青少年时剧烈活动和绝经后适度活动可能有助于降低乳腺癌风险。
