OBJECTIVES: Traffic is the most important source of community noise, and it has been proposed to be associated with a range of disease outcomes, including breast cancer. As mammographic breast density (MD) is one of the strongest risk factors for developing breast cancer, the present study investigated whether there is an association between residential exposure to traffic noise and MD in a Danish cohort.

METHODS: We included women with reproductive and lifestyle information available from the Diet, Cancer, and Health cohort, who also participated in the Copenhagen Mammography Screening Programme (n = 5,260). Present and historical addresses from 1987 to 2011 were found in national registries, and traffic noise was modeled 5 years before mammogram. Analyses between residential traffic noise and MD were performed using logistic regression.

RESULTS: We found no association between residential road and railway noise exposure 5 years before mammogram, and having a mixed/dense versus a fatty mammogram, and no interaction with menopausal status, BMI, HRT use, and railway noise exposure, for analyses on road traffic noise.

CONCLUSION: The present study does not suggest an association between residential traffic noise exposure and subsequent MD in a cohort of middle-aged Danish women.