Associação entre a exposição a partículas inaláveis (MP10) e hospitalizações por esclerose múltipla no município de São Paulo

Abstract

Introduction: Multiple sclerosis is a chronic autoimmune neurological disease characterized by the demyelination of the myelin sheath in the central nervous system, with a higher incidence in women between 20 and 40 years of age. Particulate matter pollution refers to the presence of airborne particles and is used as an indicator of air pollution. Exposure to these particles, especially fine particles, is associated with respiratory and cardiovascular diseases. Studies suggest that exposure to particulate matter may contribute to the onset and worsening of multiple sclerosis by triggering inflammatory processes and dysregulating the immune system. While the relationship between environmental factors and respiratory and cardiovascular diseases is well established, little is known about their impact on neurodegenerative and autoimmune diseases. Understanding how pollutants, temperature, and humidity influence multiple sclerosis is crucial for guiding public policies and preventive strategies. Objective: To identify the association between exposure to inhalable particles, temperature, air humidity, and the occurrence of hospitalizations due to multiple sclerosis in the municipality of São Paulo. Methods and Data: Daily data on particulate matter, relative humidity, and temperature were collected from the monitoring stations of the Environmental Company of the State of São Paulo from 2016 to 2019. Hospitalization data were obtained from the Hospital Information System database of the Department of Informatics of the Unified Health System. The Kruskal-Wallis test followed by Dunn’s post-hoc test was used to identify differences in the means of the analyzed categories. Linear, Poisson, and logistic regression models were tested, with the latter chosen to assess the association between environmental variables and hospitalizations. Results: The average concentration of particulate matter was 28.62 µg/m³, with an average temperature of 20.46 °C and average relative humidity of 75.99%. Females predominated (69.72%), and the majority of patients self-identified as white (85.86%). Temporal analyses showed significant variations in particulate matter concentrations and hospitalizations. The Kruskal-Wallis test indicated higher particulate matter values and hospitalizations on Fridays and lower values on Sundays. Logistic regression revealed a significant association between immediate exposure to particulate matter and increased hospitalizations for multiple sclerosis (lag 0 days, OR = 1.039, p < 0.001) with a 47.7% increase in the odds of hospitalization for every 10 µg/m³ increase. Significant effects were also observed at lags of six, seven, and 14 days. Discussion: The findings support previous studies that identified an association between particulate matter and disease relapse. Seasonal patterns and other environmental factors may also contribute to hospitalizations. The study data suggest that exposure to air pollutants may trigger or worsen multiple sclerosis, possibly through inflammation and immune responses caused by inhalation of fine particles. Conclusion: This study confirms a significant association between exposure to particulate matter and increased hospitalizations for multiple sclerosis, especially in short-term exposures. It highlights the importance of environmental monitoring and strategies to minimize exposure to pollutants, aiming to protect public health and improve clinical management of the disease.