Jacobsen Katja Kemp, Lynge Elsebeth, Vejborg Ilse, Tjønneland Anne, von Euler-Chelpin My, Andersen Zorana J
Department of Public Health, Center for Epidemiology and Screening, University of Copenhagen, Øster Farimagsgade 5, 1014, Copenhagen K, Denmark.
Department of Technology, Faculty of Health and Technology, Metropolitan University College, Copenhagen N, Denmark.
Cancer Causes Control. 2016 Feb;27(2):271-80. doi: 10.1007/s10552-015-0704-3. Epub 2015 Dec 8.
Smoking before first childbirth increases breast cancer risk, but the biological mechanism remains unknown and may involve mammographic density (MD), one of the strongest biomarkers of breast cancer risk. We aimed to examine whether active smoking and passive smoking were associated with MD.
For the 5,356 women (4,489 postmenopausal) from the Danish Diet, Cancer and Health cohort (1993-1997) who attended mammographic screening in Copenhagen (1993-2001), we used MD (mixed/dense or fatty) assessed at the first screening after cohort entry. Active smoking (status, duration, and intensity) and passive smoking were assessed at cohort baseline (1993-1997) via questionnaire, together with other breast cancer risk factors. Logistic regression was used to estimate associations (odds ratios, 95 % confidence intervals) between smoking and MD, adjusting for confounders.
Two thousand and twenty-six (56.5 %) women had mixed/dense MD, 2,214 (41.4 %) were current, and 1,175 (21.9 %) former smokers. Current smokers had significantly lower odds (0.86, 0.75-0.99) of having mixed/dense MD compared to never smokers, while former smoking was not associated with MD. Inverse association between smoking and MD was strongest in women who initiated smoking before age of 16 years (0.79, 0.64-0.96), smoked ≥15 cigarettes/day (0.83, 0.71-0.98), smoked ≥5 pack-years (0.62, 0.43-0.89), smoked >30 years (0.86, 0.75-0.99), and smoked ≥11 years before first childbirth (0.70, 0.51-0.96). Association between smoking and MD diminished after smoking cessation, with increased odds of having mixed/dense breasts in women who quit smoking >20 years ago as compared to current smokers (1.37, 1.01-1.67). There was no association between passive smoking and MD.
We found an inverse association between active smoking and MD.
首次分娩前吸烟会增加患乳腺癌的风险，但生物学机制尚不清楚，可能与乳房X线密度（MD）有关，MD是乳腺癌风险最强的生物标志物之一。我们旨在研究主动吸烟和被动吸烟是否与MD相关。
对于丹麦饮食、癌症与健康队列研究（1993 - 1997年）中在哥本哈根参加乳房X线筛查（1993 - 2001年）的5356名女性（4489名绝经后女性），我们采用队列入组后首次筛查时评估的MD（混合型/致密型或脂肪型）。通过问卷在队列基线（1993 - 1997年）评估主动吸烟（状态、持续时间和强度）和被动吸烟情况，同时评估其他乳腺癌风险因素。采用逻辑回归估计吸烟与MD之间的关联（比值比，95%置信区间），并对混杂因素进行调整。
2026名（56.5%）女性为混合型/致密型MD，2214名（41.4%）为当前吸烟者，1175名（21.9%）为既往吸烟者。与从不吸烟者相比，当前吸烟者患混合型/致密型MD的几率显著更低（0.86，0.75 - 0.99），而既往吸烟与MD无关。吸烟与MD之间的负相关在16岁前开始吸烟的女性中最强（0.79，0.64 - 0.96），每天吸烟≥15支（0.83，0.71 - 0.98），吸烟≥5包年（0.62，0.43 - 0.89），吸烟>30年（0.86，0.75 - 0.99），以及首次分娩前吸烟≥11年的女性中（0.70，0.51 - 0.96）。戒烟后吸烟与MD之间的关联减弱，与当前吸烟者相比，20多年前戒烟的女性患混合型/致密型乳房的几率增加（1.37，1.01 - 1.67）。被动吸烟与MD之间无关联。
我们发现主动吸烟与MD之间存在负相关。
