Reacción a "Long-term exposure to residential road traffic noise is associated with an increased risk of Parkinson's disease, study finds"

The study by Sørensen and colleagues provides, to date, the most robust evidence on the link between road traffic noise and the risk of Parkinson’s disease. It was carried out on a Danish cohort of over three million people, followed for almost two decades, with a complete residential history dating back to 1990 and an estimate of noise exposure using a validated model applied to both the façade most exposed to noise and the least exposed. One of the study’s main strengths is that it adjusts the analyses for relevant confounding factors such as air pollution, green space, socioeconomic status and, in a sub-cohort, smoking and physical activity. Sørensen et al. found a modest increase in the risk of Parkinson’s disease for each interquartile increase in noise (around 3–4 per cent), but this increase was consistent across subgroups and consistent with the pathophysiological mechanisms involved in the disease, such as oxidative stress, microglial activation and disruption of circadian rhythms. I find it particularly interesting that having a quiet façade—with a difference of at least 10 dB compared to the most exposed one—attenuates the association, as this suggests that good urban planning can help reduce exposure to this risk factor.

Although the link between traffic noise and the risk of Parkinson’s disease had already been studied in other European and Canadian cohorts, with mixed results, Sørensen’s study stands out due to the size of the population studied, the quality of the exposure estimates and the protective effect of a quiet façade.

However, the results should be interpreted with the caution typical of an observational study. Furthermore, it should be borne in mind that exposure was estimated solely on the basis of outdoor noise, without taking into account noise inside homes or exposure in other settings, such as the workplace. However, this does not detract from the relevance of the results presented in the study. Given that millions of people are exposed to noise levels exceeding those recommended by the WHO, even a small increase in risk can have a major impact on public health.