A LARGE Danish cohort study has revealed that long-term exposure to road traffic noise is associated with a higher risk of Parkinson disease, though having a quiet facade at home appeared to reduce this added risk.
Transportation noise has been proposed as a potential risk factor for Parkinson disease, but epidemiological evidence remained limited and inconsistent. Long-term road traffic noise exposure has increasingly drawn interest as a modifiable environmental factor, yet its link to Parkinson disease risk had not been comprehensively established.
Researchers conducted a Danish nationwide prospective cohort study with follow-up from 2000 to 2017, including residents aged 40 years and older. Using complete residential address histories from 1990 onward, the study assessed 10-year time-weighted exposure to road traffic noise at the most and least exposed facades of each home. Of 3,542,488 eligible individuals, 438,911 were excluded due to prevalent Parkinson disease, incomplete address history, or missing covariates, leaving 3,103,577 participants (mean baseline age 50.9 years; 51.2% female). Cases were identified via the National Patient Register and analysed using Cox proportional hazards models adjusted for sociodemographic, air pollution, and green space covariates.
Among the 3,103,577 participants, 20,587 developed Parkinson disease during follow-up. Noise at the most exposed facade was associated with a hazard ratio of 1.03 (95% CI, 1.00 to 1.05) per interquartile increment of 11.5 dB. A difference of 10 dB or more between the most and least exposed facades, indicating a quiet side, was associated with a decline in risk above 50 dB, and accounting for this difference strengthened the association with the most exposed facade (HR, 1.06; 95% CI, 1.02 to 1.09). Noise at the least exposed facade was also associated with Parkinson disease (HR, 1.04; 95% CI, 1.02 to 1.07) per interquartile increment of 8.9 dB. Associations remained consistent across sex, education, income, cohabiting status, and population density.
These findings have suggested that road traffic noise represents a novel risk factor for Parkinson disease, with a quiet residential facade appearing to mitigate the risk. As this was an observational study, causality cannot be confirmed. The authors have supported mitigation strategies ensuring residents access to a quiet side of their home, alongside further research into the underlying mechanisms.
Reference
Sørensen M et al. Road traffic noise, noise difference between residential facades, and risk of parkinson disease. JAMA Neurol. 2026;DOI:10.1001/jamaneurol.2026.2262
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