Association between noise pollution exposure and incident breast cancer in the Sister Study.

Noise exposure may contribute to cancer risk via disrupting sleep patterns and the autonomic nervous system. While modest positive associations between noise exposure and breast cancer incidence were observed in Europe, no study has been done in the United States. We examined the association between noise exposure and incident breast cancer in a large nationwide prospective cohort of women in the U.S. We included 46,809 participants in the Sister Study (ages 35-74, enrolled 2003-2009). Median daytime and nighttime anthropogenic noise at the participants' baseline residence was estimated using a U.S. National Park Service noise model. Cox proportional hazards models estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for the association between incident breast cancer and exposure to noise by quartiles and per 10 dB increase, adjusted for sociodemographic and urbanicity-related factors and stratifying by estrogen receptor (ER) status. During an average of 12.5 years of follow-up, 4,271 breast cancer cases were diagnosed. Higher daytime noise exposure was associated with higher breast cancer incidence (HR = 1.06, 95% CI = 0.99, 1.12; HR = 1.11, 95% CI = 1.02,1.21, p-for-trend = 0.03), while nighttime noise showed weaker associations (HR = 1.05, 95% CI = 0.98, 1.13). Associations for ER+ tumors were slightly elevated for both daytime (HR = 1.08; 95% CI = 1.00, 1.16) and nighttime noise (HR = 1.09; 95% CI = 0.99, 1.18). We observed a positive association between daytime noise exposure and breast cancer incidence in a large U.S cohort. Further research incorporating improved exposure assessment is needed to better understand this relationship.