Dorgan J F, Brown C, Barrett M, Splansky G L, Kreger B E, D'Agostino R B, Albanes D, Schatzkin A
Division of Cancer Prevention and Control, National Cancer Institute, Bethesda, MD 20852.
Am J Epidemiol. 1994 Apr 1;139(7):662-9. doi: 10.1093/oxfordjournals.aje.a117056.
The authors analyzed data from the Framingham Heart Study to evaluate the association between physical activity and breast cancer risk. Physical activity was ascertained by a physician-administered questionnaire from 2,321 women at the fourth biennial examination conducted in 1954-1956. Breast cancers were identified by self-report, surveillance of admissions to Framingham Union Hospital, and review of death records; all but one were histologically confirmed. During 28 years of follow-up, 117 breast cancer cases were diagnosed among the 2,307 women with data on physical activity and reproductive history (a potential confounder). Analysis was performed using Cox proportional hazards models with age as the underlying time variable. Models were adjusted for age at physical activity assessment, menopausal status, age at first pregnancy, parity, education, occupation, and alcohol ingestion. We observed a gradient of increasing risk of breast cancer with increasing physical activity (trend p = 0.06). The relative risk for women in the highest versus lowest activity quartile was 1.6 (95% confidence interval 0.9-3.0; p = 0.13). Although both moderate-to-heavy leisure and occupational activities were associated with an increased risk, the association was marginally significant only for leisure activity (p = 0.06). Our findings do not support a protective effect of physical activity during adulthood for breast cancer, but suggest an increased risk among more active women.
作者分析了弗雷明汉心脏研究的数据，以评估身体活动与乳腺癌风险之间的关联。在1954年至1956年进行的第四次两年一次检查中，通过医生管理的问卷对2321名女性的身体活动情况进行了确定。乳腺癌通过自我报告、对弗雷明汉联合医院入院情况的监测以及死亡记录审查来识别；除1例之外均经组织学确诊。在28年的随访期间，在2307名有身体活动和生殖史数据（一个潜在混杂因素）的女性中，确诊了117例乳腺癌病例。分析采用以年龄为基本时间变量的Cox比例风险模型进行。模型针对身体活动评估时的年龄、绝经状态、首次怀孕年龄、产次、教育程度、职业和饮酒情况进行了调整。我们观察到随着身体活动增加，乳腺癌风险呈梯度上升（趋势p = 0.06）。活动量最高四分位数与最低四分位数的女性相比，相对风险为1.6（95%置信区间0.9 - 3.0；p = 0.13）。虽然中度至重度休闲活动和职业活动均与风险增加相关，但仅休闲活动的关联具有边缘显著性（p = 0.06）。我们的研究结果不支持成年期身体活动对乳腺癌有保护作用，而是表明活动较多的女性风险增加。
