Study Results Link Road Traffic Noise to Higher Risk of Parkinson Disease

People with long-term residential exposure to higher levels of road traffic noise had a modestly higher risk of Parkinson disease (PD), according to results from a nationwide Danish cohort study published in JAMA Neurology.

Investigators evaluated 3,103,577 residents of Denmark aged 40 years and older who were free of PD at baseline and followed up from 2000 through 2017. Incident PD cases were identified through the Danish National Patient Register. Using complete residential address histories beginning in 1990, investigators estimated 10-year time-weighted road traffic noise exposure at both the most exposed and least exposed residential facades.

The analysis included adjustment for individual- and area-level sociodemographic factors, air pollution, and green space. Investigators also evaluated the difference in noise levels between the most and least exposed residential facades as an indicator of whether a residence had access to a quieter side.

Cohort and Exposure Findings

• Among 3,103,577 participants, 20,587 developed PD during follow-up.
• Mean baseline age was 50.9 years, and 51.2% of participants were female.
• In fully adjusted models, each interquartile increment of 11.5 dB in road traffic noise at the most exposed facade was associated with higher PD risk (hazard ratio [HR], 1.03; 95% CI, 1.01 to 1.05).
• After accounting for the difference between noise at the most and least exposed facades, the association between noise at the most exposed facade and PD risk was stronger (HR, 1.05; 95% CI, 1.02 to 1.08).
• Each interquartile increment of 8.9 dB in noise at the least exposed facade was associated with higher PD risk (HR, 1.04; 95% CI, 1.02 to 1.06).
• A residential noise difference of 10 dB or greater between the most and least exposed facades was associated with lower PD risk across higher categories of noise exposure at the most exposed facade.
• Associations were generally consistent across subgroups defined by sex, education, income, cohabiting status, and population density.
• In a subpopulation with available lifestyle data, additional adjustment for smoking and physical activity resulted in only minor changes in risk estimates.

What Do the Data Mean for Neurologists?

The authors noted that the findings support mitigation strategies that preserve or create a quieter residential facade, alongside established traffic-noise reduction approaches such as noise barriers, quieter road surfaces, and urban planning measures.

Several limitations should be considered. PD cases were identified through a national hospital registry, which may not capture people diagnosed exclusively in neurology practices. Noise exposure was estimated at residential facades rather than indoors, so the analysis could not account for sound insulation, window type, ventilation, bedroom location, commuting, workplace noise, or other time-activity patterns. Lifestyle data were unavailable in the full cohort, although adjustment for smoking and physical activity in a subpopulation produced similar results. The study was conducted in Denmark, and findings may not generalize to countries with different housing, traffic, environmental, or health care patterns.

Source

Sørensen M, Poulsen AH, Raaschou-Nielsen O, et al. Road traffic noise, noise difference between residential facades, and risk of Parkinson disease. JAMA Neurol. Published online July 20, 2026. doi:10.1001/jamaneurol.2026.2262