ESR1 and breast cancer: In the fully adjusted models, we found a positive and statistically significant association between each 10 dB increase in residential road traffic noise levels at the residence (24-year mean noise levels preceding diagnosis) and incidence of BC, ranging from a 10% (HR; 95% CI, 1.10; 1.00–1.20) increase in total BC incidence (N = 1193), to a 17% (HR; 95% CI, 1.17; 1.02–1.33) increase in incidence based on the 611 BC cases with ER and PR information (Table 2).