Residential noise exposure and the longitudinal risk of hospitalization for depression after pregnancy: Postpartum and beyond

Abstract Objective Depression is a major public health concern, but the link with the built environment is unclear. We sought to determine the relationship between residential noise during pregnancy and later risk of severe depression in women. Methods We analyzed a population-based cohort of 140,456 women with no documented history of mental illness who were pregnant in Montreal between 2000 and 2016. We obtained residential noise estimates (LA eq. 24 h , L den , L night ) from land use regression models, and followed the women over time for up to 18 years after pregnancy to identify subsequent hospitalizations for depression or other mental disorders. We used Cox regression to compute hazard ratios and 95% confidence intervals (CI) adjusted for maternal characteristics. Results There were 8.0 incident hospitalizations for depression and 16.4 for other mental disorders per 10,000 person-years in women exposed to an LA eq. 24 h of 60–64.9 dB(A). The incidence was lower for noise at eq. 24 h of 60 dB(A) was associated with 1.16 times (95% CI 0.84–1.62) the risk of depression hospitalization, and 1.34 times (95% CI 1.04–1.74) the risk of other mental disorders. Associations were more prominent for L night , with 1.32 times (95% CI 1.08–1.63) the risk of depression hospitalization at 60 dB(A) and 1.68 times the risk (95% CI 1.05–2.67) at 70 dB(A). Conclusions Pregnant women exposed to noise, especially nighttime noise, have a greater risk of hospitalization for depression and other mental disorders later in life. Residential noise may be a risk factor for depression after pregnancy.