Air pollution is a possible risk factor for MS

Air pollution could be a risk factor for the development of multiple sclerosis (MS). An Italian study in the province of Pavia –one of the most polluted areas in Europe– found a relationship between MS risk and high concentrations of the fine pollutant particulate matter PM2.5 in the air [1].

MS is associated with multiple genetic and environmental risk factors. Some environmental factors have been extensively studied, including vitamin D levels and smoking, but not air pollution. Airborne PM is a complex mixture of solids and aerosols. PM10 includes particles with a diameter of 10 μm or less, PM2.5 have a diameter of 2.5 μm or less that can penetrate even further into the lungs.

The researchers identified 927 MS patients resident in the province of Pavia (547,251 inhabitants) in Lombardy, Italy. They gathered spatial emission data for PM2.5 concentrations in winter, when PM concentrations peak. Municipalities were stratified into 3 groups by tertiles according to PM2.5 concentrations.

The overall MS prevalence in Pavia was 169.4 per 100,000 inhabitants, compared to 16 per 100,000  in 1974. In 2 of the 3 groups of municipalities, air pollution levels were above the European Commission threshold of 25 µg/m³. In the 2 groups with high air pollution levels, the risk of MS was 29% higher than in the third group with lower air pollution levels, which is a significant difference. The Bayesian map showed consistent high-risk clusters with an excess number of MS cases. The authors hope that this will encourage analytical studies in high-risk areas to analyse multiple environmental factors related to the uneven distribution of MS.

1. Bergamaschi RGE, et al. Abstract EPR1151, EAN 2020.

Posted on 10 September 20205 November 2020