Largest Study Yet Links Traffic Noise to Parkinson's Risk

A study tracking 3.1 million people in Denmark for 18 years found that long-term exposure to road traffic noise is linked to a higher risk of Parkinson's disease. Each noticeable rise in noise level added about 3% to the risk. Experts caution the study cannot prove noise directly causes the disease. The WHO already ranks traffic noise as Europe's second-biggest environmental health threat after air pollution.