Impact of Earplugs on Mechanisms of Noise-Related Cardiovascular Disease

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.

Inclusion criteria

• Describe feeling annoyed by transportation noise exposure or have high residential noise exposure (>45 dBA average over 24 hours) using the United States Department of Transportation Map
• Known stable atherosclerosis or at least one typical risk factor (i.e., hypertension, diabetes, active smoking, or hyperlipidemia)
• Ability to understand and sign informed consent

Exclusion criteria

• History of stroke, brain surgery, or seizure
• Use of certain CVD medications (e.g., beta-blockers, high-intensity statins [e.g., rosuvastatin 20/40 mg and atorvastatin 40/80 mg], PCSK-9 inhibitors)
• Psychiatric or cardiovascular medication change within 3 months (i.e., stable regimen is allowed)
• Unstable blood pressure or cardiac arrhythmia
• Current use of personal noise mitigation techniques or involvement in stress management program
• Moderate/severe alcohol/substance use disorder
• Current mania/psychosis
• Weight >300 lbs.
• Claustrophobia
• Pregnancy
• Metal implants
• Uncontrolled hyperglycemia (HgbA1c>7.5%)
• Subjects who have had significant radiation exposure as part of research (>2 nuclear tests, computed tomography images, or fluoroscopic procedures) during the preceding 12-months