Although physical activity is associated with lower breast cancer risk for average-risk women, it is not known if this association applies to women at high familial/genetic risk. We examined the association of recreational physical activity (self-reported by questionnaire) with breast cancer risk using the Prospective Family Study Cohort, which is enriched with women who have a breast cancer family history ( N = 15,550). We examined associations of adult and adolescent recreational physical activity (quintiles of age-adjusted total metabolic equivalents per week) with breast cancer risk using multivariable Cox proportional hazards regression, adjusted for demographics, lifestyle factors, and body mass index. We tested for multiplicative interactions of physical activity with predicted absolute breast cancer familial risk based on pedigree data and with BRCA1 and BRCA2 mutation status. Baseline recreational physical activity level in the highest four quintiles compared with the lowest quintile was associated with a 20% lower breast cancer risk (HR, 0.80; 95% confidence interval, 0.68–0.93). The association was not modified by familial risk or BRCA mutation status ( P interactions >0.05). No overall association was found for adolescent recreational physical activity. Recreational physical activity in adulthood may lower breast cancer risk for women across the spectrum of familial risk. Significance: These findings suggest that physical activity might reduce breast cancer risk by about 20% for women across the risk continuum, including women at higher-than-average risk due to their family history or genetic susceptibility. See related commentary by Niehoff et al., [p. 23][1] [1]: /lookup/volpage/80/23?iss=1

中文翻译：

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娱乐活动与降低罹患乳腺癌高风险的成年女性患乳腺癌的风险有关：一项针对选择患有家族遗传风险的女性的队列研究

尽管体育锻炼与中等风险女性的乳腺癌风险较低相关，但尚不清楚这种关联是否适用于家族/遗传风险较高的女性。我们使用前瞻性家庭研究队列研究了娱乐性体育活动（通过问卷自行报告）与乳腺癌风险的关系，该研究队列丰富了有乳腺癌家族病史的妇女（N = 15550）。我们使用多变量Cox比例风险回归，人口统计学，生活方式因素和体重指数进行了调整，检验了成人和青少年娱乐活动（每周经年龄调整的总代谢当量的五分之一）与乳腺癌风险的关联。我们根据谱系数据以及BRCA1和BRCA2突变状态，测试了体育活动与预测的绝对乳腺癌家族风险的乘法相互作用。与最低的五分位数相比，最高的四分位数的基线娱乐体育活动水平与乳腺癌风险降低20％相关（HR，0.80； 95％的置信区间，0.68–0.93）。家族风险或BRCA突变状态未改变该关联（P相互作用> 0.05）。未发现青少年娱乐性体育活动的总体关联。在成年期进行娱乐性体育锻炼可以降低妇女在整个家族风险中的乳腺癌风险。启示：这些发现表明，体育锻炼可以使女性在整个风险连续过程中患乳腺癌的风险降低约20％，包括因其家族史或遗传易感性而处于高于平均风险的妇女。参见Niehoff等人的相关评论，[p。23] [1] [1]：/ lookup / volpage / 80/23？iss = 1