A common neighborhood nuisance could be doing serious harm to your health, new research has suggested.  

A large new study has found that long-term exposure to road traffic noise may increase the risk of developing Parkinson's disease.

Researchers followed more than 3 million adults for nearly two decades and found a modest but consistent link between traffic noise levels and the neurodegenerative disorder. 

Even small increases in noise were associated with a higher risk and the connection held up even after accounting for other factors like air pollution, green space, income and education.

Parkinson's affects about 1.1 million Americans, with nearly 90,000 new diagnoses made each year. Numbers are expected to rise as populations age, making it more urgent than ever to identify modifiable risk factors.

The disorder is characterized by the progressive loss of nerve cells that produce dopamine, a chemical essential for controlling movement. This leads to tremors, slowed movement, rigid muscles and balance problems.

Parkinson’s also causes non-motor symptoms including sleep disturbances, depression and cognitive decline.

While the study did not prove that noise directly causes Parkinson's, experts say it adds to a growing body of evidence that chronic environmental noise is not only an annoyance, but also a public health threat that has long gone ignored.

Study co-author Thomas Munzel, an environmental cardiologist at the University Medical Center Mainz in Germany, told the Guardian that exposure to chronic noise is 'still a young entrant in the Parkinson’s disease risk-factor literature,' so the authors hope the findings encourage more research into the matter. 

Previous research in 2025 found exposure to loud noises could produce motor deficits in mice whose brains were altered to mimic Parkinson's disease and several smaller studies have found a relationship between traffic noise and the disorder. 

However, this new study 'goes a step further,' researchers said, as it includes a much larger dataset and accounts for other variables that may also influence Parkinson's disease risk. 

For the study, published in the journal JAMA Neurology, the authors analyzed whether participants developed Parkinson's disease between 2000 and 2017. 

Nearly 20,600 people were diagnosed with the disease during the study period.

Researchers then analyzed traffic noise at the loudest and quietest points in the houses of all study participants. 

Results showed that for every increase of just 11.5 decibels - equivalent to just louder than normal breathing - in traffic noise at the loudest point, the risk of developing Parkinson's disease increased by three percent. 

On the side of people's homes least exposed to sound, every 9-decibel increase of noise raised the risk of the condition by four percent. 

Experts not involved in the study wrote in an accompanying editorial: 'These findings suggest that road traffic noise may be a novel environmental risk factor for [Parkinson’s].'

Researchers also found that where a person sleeps in their home may matter. People whose homes had a significant difference between their noisiest and quietest sides had a lower risk, even if the front of their house was loud. 

The authors did not posit why traffic noise was associated with an increased Parkinson's disease risk, but previous research suggests disruptive sounds can interrupt sleep and trigger a stress response that activates the production of molecules that can cause cellular damage in the brain and may play a role in development of the condition. 

Jannette Rodríguez Pallares, a neurobiologist at the University of Santiago de Compostela who wasn’t involved in the research, wrote in the accompanying editorial: 'Although it is unlikely that noise directly causes the death of [nerve cells], it may impair the brain’s protective mechanisms and promote biological processes involved in disease development.'