Impact of Earplugs on Mechanisms of Noise-Related Cardiovascular Disease

Overview

Noise from cars, planes, and trains affects all people and has been associated with heart disease. Almost 30% of Americans are exposed to harmful levels of noise and noise accounts for the loss of more than one million healthy life years per year in Europe. Noise causes stress and may be most dangerous when it happens at night. The mechanisms linking noise to heart disease involve changes in the brain and the "fight or flight" response. These changes lead to inflammation and blood vessel disease. However, there are few laws that restrict noise and it is not addressed in medical care. Further, as cities and industries grow, noise continues to increase. Moreover, noise often occurs in areas that are also exposed to other stressors like high air pollution and low income. Yet, there is little research on noise, and it is not known if lowering noise exposure helps heart health. The investigators will use imaging to test if earplugs that block noise improve stress symptoms and changes in the the brain, blood vessels, and stress pathways that lead to disease. The investigators expect that people who use earplugs will have lower measures of stress and heart disease at follow-up. The study will include 26 people with heart disease risk with high noise exposure or who are annoyed by noise. At the first visit, subjects will have imaging of the brain and blood vessels and will have assessments of stress, inflammation, and the "fight or flight" response. They will be assigned to use earplugs or not after the first visit. After 6 months, imaging and other testing will be repeated. It will help to understand how noise impacts the body and whether the effects can be changed. It may also identify important treatments to prevent heart disease in people exposed to noise. By testing if the adverse effects of noise can be lowered with earplugs, this project supports the AHA's mission to be a force for a world of longer and healthier lives.

Transportation noise is a pervasive exposure in modern life that has been associated with cardiovascular and metabolic disease. Almost 30% of Americans are exposed to harmful levels of noise and noise accounts for the loss of more than one million healthy life years per year in Europe. Noise exposure leads to activation of the stress response and nocturnal exposure may be more dangerous. The pathologic mechanisms linking noise to cardiovascular disease have recently been shown to involve changes in the metabolic activity of stress responsive brain regions (specifically the ratio of activity in the amygdala to that of the cortex or stress-associated neural activity, SNA) and fluorodeoxyglucose positron emission tomography, FDG PET) and autonomic dysfunction. These changes lead to stress hormone release, inflammation, vascular dysfunction, oxidative stress, increased cardiovascular risk factors, and, ultimately, atherosclerosis. However, there are few laws that restrict noise and it is not addressed in routine medical care. Further, as cities and industries grow, noise exposure continues to increase. Moreover, noise exposure often occurs coincidentally with other psychosocial and environmental stressors, such as high air pollution and low income. Yet, there is little research on noise, and it is not known if personal noise mitigation attenuates the stress response and downstream markers of cardiovascular risk. The investigators will leverage will use advanced FDG PET/magnetic resonance imaging to test if noise canceling earplugs improve stress symptoms and reduce SNA, arterial inflammation, and autonomic and inflammatory intermediaries. The study will assess whether earplug use will decrease SNA and arterial inflammation by attenuating autonomic and inflammatory intermediaries. The investigators will recruit 26 people with cardiovascular risk with high noise exposure or annoyance for this pilot study. At baseline, subjects will have FDG PET/MRI of the brain and aorta and will have assessments of stress, inflammation, and autonomic function. They will be randomized to use earplugs or control. After 6 months, the baseline visit will be repeated. This study will clarify how noise impacts the body and whether its adverse effects can be reduced. It may also identify novel treatments to prevent heart disease in people exposed to noise. By testing if the adverse effects of noise can be mitigated with earplugs, this study takes a necessary step towards reducing noise-related cardiovascular disease.