Cigarette smoking and mammographic breast density in post-menopausal women from the EPIC Florence cohort

Benedetta Bendinelli; Saverio Caini; Melania Assedi; Ilaria Ermini; Elisa Pastore; Luigi Facchini; Maria Antonietta Gilio; Giacomo Duroni; Miriam Fontana; Andrea Querci; Daniela Ambrogetti; Calogero Saieva; Giovanna Masala

doi:10.3389/fonc.2024.1335645

Cigarette smoking and mammographic breast density in post-menopausal women from the EPIC Florence cohort

Front Oncol. 2024 Mar 7:14:1335645. doi: 10.3389/fonc.2024.1335645. eCollection 2024.

Affiliations

¹ Clinical Epidemiology Unit, Institute for Cancer Research, Prevention and Clinical Network (ISPRO), Florence, Italy.
² Cancer Risk Factors and Lifestyle Epidemiology Unit, Institute for Cancer Research, Prevention and Clinical Network (ISPRO), Florence, Italy.
³ Breast Cancer Screening Branch, Institute for Cancer Research, Prevention and Clinical Network (ISPRO), Florence, Italy.

Abstract

Introduction: Cigarette smoking has been recognized as a risk factor for breast cancer (BC) also if the biological mechanism remains poorly understood. High mammographic breast density (MBD) is associated with BC risk and many BC risk factors, such as genetic, anthropometric, reproductive and lifestyle factors and age, are also able to modulate MBD. The aim of the present study was to prospectively explore, in post-menopausal women, the association between smoking habits and MBD, assessed using an automated software, considering duration and intensity of smoking.

Methods: The analysis was carried out in 3,774 women enrolled in the European Prospective Investigation into Cancer and Nutrition (EPIC) Florence cohort in 1993-98, participating in the 2004-06 follow up (FU) and with at least one full-field digital mammography (FFDM) performed after FU. For each woman, detailed information on smoking habits, anthropometry, lifestyle and reproductive history was collected at enrollment and at FU. Smoking information at baseline and at FU was integrated. The fully automated Volpara™ software was used to obtain total breast volume (cm³), absolute breast dense volume (DV, cm³) and volumetric percent density (VPD, %) from the first available FFDM (average 5.3 years from FU). Multivariable linear regression models were applied to evaluate the associations between smoking habits and VPD or DV.

Results: An inverse association between smoking exposure and VPD emerged (Diff% -7.96%, p <0.0001 for current smokers and -3.92%, p 0.01 for former smokers, compared with non-smokers). An inverse dose-response relationship with number of cigarettes/day, years of smoking duration and lifetime smoking exposure (pack-years) and a direct association with time since smoking cessation among former smokers emerged. Similar associations, with an attenuated effect, emerged when DV was considered as the outcome variable.

Discussion: This longitudinal study confirms the inverse association between active smoking, a known risk factor for BC, and MBD among post-menopausal women. The inclusion of smoking habits in the existing BC risk prediction models could be evaluated in future studies.

Keywords: breast cancer; cigarette smoking; lifestyle; mammographic breast density; post-menopausal women.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. The research leading to these results has received funding from the Italian Ministry of Health (RF-2016–02364745 to GM) and from the Associazione Italiana per la Ricerca contro il Cancro (AIRC) under IG 2019 – ID. 23702 – P.I. GM. The funding sources had no role in the design and conduct of the study, collection, management, analysis and interpretation of the data, preparation, review or approval of the manuscript and decision to submit the manuscript for publication.