Tehard Bertrand, Friedenreich Christine M, Oppert Jean-Michel, Clavel-Chapelon Francoise
Equipe Institut National de la Sante et de la Recherche Medicale Nutrition, Hormones et Cancer, Institut Gustave Roussy, 39 rue Camille Desmoulins, 94805 Villejuif Cedex, France.
Cancer Epidemiol Biomarkers Prev. 2006 Jan;15(1):57-64. doi: 10.1158/1055-9965.EPI-05-0603.
There is a need to investigate the type, duration, frequency, and intensity of physical activity that are critical to reduce the risk of breast cancer, and if this relation differs among subgroups of women.
We analyzed the relation between physical activity and breast cancer incidence between 1990 and 2002 (n=3,424 cases), among 90,509 women of the French E3N cohort, ages between 40 and 65 years in 1990. We gave special attention to effect modification by body mass index (BMI), family history of breast cancer, parity, and hormone replacement therapy (HRT).
A linear decrease in risk of breast cancer was observed with increasing amounts of moderate (P(trend)<0.01) and vigorous (P(trend)<0.0001) recreational activities. Compared with women who reported no recreational activities, those with more than five weekly hours of vigorous recreational activity had a relative risk of 0.62 (0.49-0.78). This decrease was still observed among women who were overweight, nulliparous, had a family history of breast cancer, or used HRT. Compared with the whole cohort, among nulliparous women, the reduction of risk observed was of a higher magnitude, although the test for heterogeneity did not reach statistical significance.
A risk reduction of breast cancer was particularly observed with vigorous recreational activity. Further investigations are needed to confirm that intensity is an important variable to consider in risk reduction and to identify the precise biological mechanisms involved in such a risk reduction.
有必要研究对降低乳腺癌风险至关重要的身体活动的类型、持续时间、频率和强度，以及这种关系在女性亚组中是否存在差异。
我们分析了1990年至2002年间法国E3N队列中90509名年龄在40至65岁之间的女性（n = 3424例）的身体活动与乳腺癌发病率之间的关系。我们特别关注体重指数（BMI）、乳腺癌家族史、生育情况和激素替代疗法（HRT）对效应的修正作用。
随着中度（P趋势<0.01）和剧烈（P趋势<0.0001）休闲活动量的增加，乳腺癌风险呈线性下降。与报告无休闲活动的女性相比，每周进行超过五小时剧烈休闲活动的女性相对风险为0.62（0.49 - 0.78）。在超重、未生育、有乳腺癌家族史或使用HRT的女性中也观察到了这种下降。与整个队列相比，在未生育女性中观察到的风险降低幅度更大，尽管异质性检验未达到统计学显著性。
特别观察到剧烈休闲活动可降低乳腺癌风险。需要进一步研究以确认强度是降低风险时需要考虑的重要变量，并确定这种风险降低所涉及的精确生物学机制。
