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

Area of Science:

• Oncology
• Radiology
• Epidemiology

Background:

• Cigarette smoking is a recognized breast cancer (BC) risk factor, though biological mechanisms are unclear.
• High mammographic breast density (MBD) is associated with BC risk and influenced by various factors including lifestyle.
• Understanding factors modulating MBD is crucial for BC risk assessment.

Purpose of the Study:

• To prospectively investigate the association between smoking habits and MBD in post-menopausal women.
• To assess the impact of smoking duration and intensity on MBD.
• To explore the relationship between smoking and volumetric breast density measures.

Main Methods:

• Analysis of 3,774 women from the European Prospective Investigation into Cancer and Nutrition (EPIC) Florence cohort.
• Collection of detailed smoking, anthropometric, lifestyle, and reproductive history data.
• Automated assessment of total breast volume, absolute dense volume (DV), and volumetric percent density (VPD) using Volpara™ software.

Main Results:

• An inverse association was found between smoking exposure and VPD (current smokers: -7.96%; former smokers: -3.92%).
• A dose-response relationship was observed with smoking intensity, duration, and lifetime exposure (pack-years).
• Former smokers showed a direct association with time since smoking cessation; similar trends were seen for DV.

Conclusions:

• This longitudinal study confirms an inverse association between active smoking and MBD in post-menopausal women.
• Smoking habits may influence MBD, a factor implicated in breast cancer risk.
• Future research could evaluate incorporating smoking habits into BC risk prediction models.