A pioneering study has found that long-term exposure to road traffic noise is associated with a higher risk of Parkinson's disease, the largest investigation of its kind to date. Researchers observed a modest but consistent increase in risk, with every 11.5-decibel rise in noise levels at the most exposed facade of a residence corresponding to a 3% increase in Parkinson's risk over the 18-year study period.
Study details and findings
The research, published in JAMA Neurology, included 3.1 million Danish participants aged 40 and older, tracked using nationwide health register data. This made it the largest study on road traffic noise and Parkinson's disease. The team modelled noise exposure at both the most and least exposed sides of each participant's home and calculated the difference. They found that having a quieter part of the home—such as a bedroom on the less exposed side—could mitigate the association between noise and higher Parkinson's risk.
Existing research has identified potential biological pathways linking noise exposure to Parkinson's, primarily through stress responses and disrupted sleep. Chronic noise exposure exceeding World Health Organization thresholds affects nearly one-third of Europeans, according to the study.
Expert perspectives
Thomas Münzel, one of the study's authors, said environmental noise is “still a young entrant in the Parkinson’s disease risk-factor literature.” He added that the findings should move noise from a speculative to a credible risk factor, prompting further research. The researchers accounted for air pollution but lacked data on participants' lifestyles. However, they argue that lifestyle factors would not alter the results, as the association remained consistent regardless of education and income levels.
Anna Hansell, a professor of environmental epidemiology at the University of Leicester not involved in the study, noted that noise is “more likely to be a general stressor” rather than a specific environmental risk factor for Parkinson's, and that the study design “doesn’t ‘prove’ causation.” Dr Peter Chan, a senior researcher at the Nuffield Department of Population Health, said the analysis of noise differences within homes “is interesting as it highlights a dimension of noise issue that noise at home is not uniform and people can mitigate by moving to different rooms.” However, he cautioned that many Parkinson's risk factors are linked to low socioeconomic status, making it hard to isolate noise's effect.
Implications for policy
John Stewart, chair of the UK Noise Association, commented: “This research joins a growing list of studies which show a connection between traffic noise and people’s physical and mental health. It shows the link is strongest where the noise is loudest. In practice, this means main roads. That suggests governments and local authorities should focus their efforts on cutting main road noise.”
Previous research has linked neurological disorders, including Parkinson's, to environmental toxins such as air pollution, microplastics, and pesticides. This study is among the first to implicate noise pollution directly, highlighting a need for updated prevention strategies.
