Climate change represents a threat to human health. In this research, we have investigated the sensitivity of Parkinson's disease (PD) to climate change, and assessed whether there is any detectable link between climate warming and key PD indices.

We contrasted variations between 1990 and 2016 of PD patients’ indices (prevalence, deaths, and disability-adjusted life years) and climate indices (warming and annual average temperature) for 185 countries. Countries were clustered in four categories, depending on whether they had higher-than-median or lower-than-median warming, and higher-than-median or lower-than-median temperature. For all four clusters, we assessed the relationship between variations in PD patients’ indices, and climate indices.

In the cluster of the 25 countries (home to about 900 million people) characterized by higher-than-average warming and higher-than-average temperature, we have found a positive correlation between more intense warming and higher variations in the PD indices: in other words, warmer countries that have experienced more intense warming have reported a larger increase in PD cases.

These results indicate that in warmer-than-average countries, i.e., countries that have in general a warmer climate, climate change has an impact on PD that depends on the intensity of the warming: the more intense the warming, the stronger the impact. In other worlds, climate change should be considered as one of the ‘environmental factors’ that can impact PD.