The Relation Between Air Pollution and Multiple Sclerosis Hospitalization in Kerman

Abstract

Background: Air pollutants may harm the nervous system and act as environmental risk factors for increased hospitalizations and relapses in multiple sclerosis (MS). Objectives: This study aimed to assess the potential association between MS hospitalizations and ambient air pollutants, including CO, O3, SO2, NO2, PM10, and PM2.5, in Kerman, Iran. Methods: This ecological study used air pollution and meteorological data obtained from the Kerman Environmental Protection Agency and the Kerman Meteorology Organization, respectively. Multiple sclerosis hospitalization data were obtained from the Shafa Hospital MS Registry in Kerman. Generalized additive models (GAMs) were used to estimate rate ratios (RRs) for air pollutants in predicting MS hospitalization after adjusting for temperature, relative humidity, seasonality, weekdays, and long-term trends, using lags of up to 7 days. Results: During 2008 - 2020, 4,913 MS hospitalizations occurred among patients with MS in Kerman, of which 3,739 were in females. Significant associations were observed between MS hospitalization and CO in individuals aged < 30 years (RR = 1.5647 at lag 0), O3 in individuals aged > 50 years (RR = 1.0161 at lag 5), SO2 in individuals aged > 50 years (RR = 1.0253 at lag 5), NO2 in females (RR = 1.0121 at lag 0), PM10 in individuals aged > 50 years (RR = 0.9828 at lag 3), and PM2.5 in individuals aged > 50 years (RR = 0.9832 at lag 5). Conclusions: Ambient O3 and NO2, and more consistently, CO and SO2, were associated with increased MS hospitalizations in Kerman.