Smoking and risk of breast cancer in the Generations Study cohort

Abstract

BackgroundPlausible biological reasons exist regarding why smoking could affect breast cancer risk, but epidemiological evidence is inconsistent.MethodsWe used serial questionnaire information from the Generations Study cohort (United Kingdom) to estimate HRs for breast cancer in relation to smoking adjusted for potentially confounding factors, including alcohol intake.ResultsAmong 102,927 women recruited 2003–2013, with an average of 7.7 years of follow-up, 1815 developed invasive breast cancer. The HR (reference group was never smokers) was 1.14 (95% CI 1.03–1.25; P = 0.010) for ever smokers, 1.24 (95% CI 1.08–1.43; P = 0.002) for starting smoking at ages < 17 years, and 1.23 (1.07–1.41; P = 0.004) for starting smoking 1–4 years after menarche. Breast cancer risk was not statistically associated with interval from initiation of smoking to first birth (P-trend = 0.97). Women with a family history of breast cancer (ever smoker vs never smoker HR 1.35; 95% CI 1.12–1.62; P = 0.002) had a significantly larger HR in relation to ever smokers (P for interaction = 0.039) than women without (ever smoker vs never smoker HR 1.07; 95% CI 0.96–1.20; P = 0.22). The interaction was prominent for age at starting smoking (P = 0.003) and starting smoking relative to age at menarche (P = 0.0001).ConclusionsSmoking was associated with a modest but significantly increased risk of breast cancer, particularly among women who started smoking at adolescent or peri-menarcheal ages. The relative risk of breast cancer associated with smoking was greater for women with a family history of the disease.Electronic supplementary materialThe online version of this article (doi:10.1186/s13058-017-0908-4) contains supplementary material, which is available to authorized users.

Transforming growth factor beta 1 polymorphisms and haplotypes associated with breast cancer susceptibility: A case-control study in Tunisian women

“…Significant differences between controls and BC cases were noted in the prevalence of smoking, in agreement with findings elsewhere. 36,37 Higher prevalence of women with irregular menses, and previous/current users of oral contraceptives were seen in BC cases than in control women. This was reminiscent of findings which documented association of irregular menses 38,39 and oral contraceptive use 38,40 with increased incidence of BC.…”

Long‐term exposure to extremely low‐dose of nicotine and 4‐(methylnitrosamino)‐1‐(3‐pyridyl)‐1‐butanone (NNK) induce non‐malignant breast epithelial cell transformation through activation of the a9‐nicotinic acetylcholine receptor‐mediated signaling pathway

“…Several studies were conducted on first‐hand smokers (active smokers), focusing on the effects of Nic or NNK at different doses to determine the risk of developing breast and lung cancer and the underlying molecular mechanisms . The researchers used different doses of Nic starting from highest doses of 10 μM of Nic and 1 μM of NNK to the lowest dose of 1 nM and 100pM for Nic and NNK, respectively, in normal and cancerous breast cells .…”

Untitled

“…Moreover, nanoparticles conjugated to cancer-specific ligands could be used in early identification of tumours, allowing early intervention with a chemopreventive agent. Several nanotechnological approaches have been used to improve delivery of chemotherapeutic agents to cancer cells with the goal of minimizing toxic effects on healthy tissues while maintaining antitumour efficacy 14 192 has been reported the plausible biological reasons exist regarding why smoking could affect breast cancer risk, but epidemiological evidence is inconsistent. In this study, 102, 927 women recruited 2003-2013, with an average of 7.7 years of follow-up, 1815 developed invasive breast cancer.…”