Cui Yan, Miller Anthony B, Rohan Thomas E
Department of Epidemiology and Population Health, Albert Einstein College of Medicine, 1300 Morris Park Ave, Belfer 1301D, Bronx, NY 10461, USA.
Breast Cancer Res Treat. 2006 Dec;100(3):293-9. doi: 10.1007/s10549-006-9255-3. Epub 2006 Jun 14.
The results of epidemiologic studies of the association between cigarette smoking and breast cancer risk have been inconsistent. In spite of the inconsistency, several recent analyses have suggested an increased risk of breast cancer among women who smoked cigarettes for a long period of time and/or who started smoking before their first pregnancy. Our analyses were conducted in the Canadian National Breast Screening Study (NBSS), a multi-center, randomized controlled trial of mammographic screening for breast cancer among 89,835 women aged 40-59 at enrollment. Participants were recruited between 1980 and 1985 from the general Canadian population. During an average of 16.1 years of follow-up, we identified 4,445 incident breast cancer cases. We used the Cox proportional hazards models to estimate multivariate rate ratios (RRs) and 95% confidence limits (CLs) for the association between cigarette smoking and breast cancer. We found that breast cancer risk was associated with the duration (40 years versus 0: RR = 1.50, 95% CL = 1.19, 1.89), intensity (40 cigarettes per day versus 0: RR = 1.20, 95% CL = 1.00, 1.44), cumulative exposure (40 pack-years versus 0: RR = 1.17, 95% CL = 1.02, 1.34), and latency of cigarette smoking (40 years since commencement of smoking versus 0: RR = 1.28, 95% CL = 1.06, 1.55), as well as smoking initiation before a first full-term pregnancy (among parous women, more than 5 years of smoking versus 0: RR = 1.13, 95% CL = 1.01-1.25). These results strongly suggest that cigarette smoking might play an important role in the etiology of breast cancer, particularly when initiated relatively early in life and when engaged in for long durations.
关于吸烟与乳腺癌风险之间关联的流行病学研究结果并不一致。尽管存在不一致性，但最近的几项分析表明，长期吸烟和/或在首次怀孕前就开始吸烟的女性患乳腺癌的风险有所增加。我们的分析是在加拿大国家乳腺筛查研究（NBSS）中进行的，这是一项针对89835名年龄在40至59岁之间（入组时）的女性进行乳腺癌钼靶筛查的多中心随机对照试验。参与者于1980年至1985年期间从加拿大普通人群中招募。在平均16.1年的随访期间，我们确定了4445例新发乳腺癌病例。我们使用Cox比例风险模型来估计吸烟与乳腺癌之间关联的多变量率比（RRs）和95%置信区间（CLs）。我们发现，乳腺癌风险与吸烟持续时间（40年与0年：RR = 1.50，95% CL = 1.19，1.89）、吸烟强度（每天40支与0支：RR = 1.20，95% CL = 1.00，1.44）、累积暴露量（40包年与0包年：RR = 1.17，95% CL = 1.02，1.34）以及吸烟潜伏期（开始吸烟40年与0年：RR = 1.28，95% CL = 1.06，1.55）有关，同时也与首次足月妊娠前开始吸烟有关（在经产妇中，吸烟超过5年与0年：RR = 1.13，95% CL = 1.01 - 1.25）。这些结果有力地表明，吸烟可能在乳腺癌的病因学中起重要作用，尤其是在生命相对早期开始吸烟且吸烟时间较长的情况下。
