Environmental Noise Pollution and Risk of Hypertension in Pregnancy

Abstract

Background: A growing number of studies suggest that environmental noise pollution may impact the risk of hypertension, but the relationship during pregnancy is poorly understood. We investigated the association between environmental noise levels and preeclampsia, a hypertensive disorder of pregnancy.Methods: We undertook a retrospective cohort study of 269,263 pregnancies in Montreal, 2000-2013. Using postal codes, we assigned environmental noise pollution levels (dBA) from land use regression models to each pregnancy. We calculated odds ratios (OR) and 95% confidence intervals (CI) for the association of environmental noise with preeclampsia, adjusted for air pollutants, neighbourhood walkability, maternal age, parity, multiple pregnancy, comorbidity, socioeconomic deprivation, and year of delivery. We assessed if associations varied according to preeclampsia severity (mild and severe) and onset time (<34 and ≥34 weeks of gestation).Results: Women exposed to elevated environmental noise levels (≥65 vs. <50 dBA) had a higher prevalence of preeclampsia (37.9 vs. 27.9 per 1,000). Compared with 50 dBA, exposure to a noise level of 65 dBA was associated with 1.09 times the odds of preeclampsia (95% CI 0.99-1.20). Associations were stronger for severe preeclampsia (OR 1.29, 95% CI 1.09-1.54) and preeclampsia before 34 gestational weeks (OR 1.71, 95% CI 1.20-2.43). There was no association with mild preeclampsia and preeclampsia at ≥34 weeks.Conclusion: Environmental noise pollution may be a risk factor for preeclampsia, particularly severe or early onset preeclampsia. In light of rising levels of urban noise, these results suggest that vulnerable populations, including pregnant women, could benefit from residential noise reduction policies.