Effect of Air Pollutant Markers on Multiple Sclerosis Relapses.

BACKGROUND: Multiple Sclerosis (MS) is one of the autoimmune diseases with an unknown cause. The aim of this study was to explore the link between air quality and MS relapses in patients who suffer from MS. METHODS: This time-series study was conducted on patients registered at the Iranian Multiple Sclerosis Society in 2011-2012. They were randomly selected from patients lived in Tehran in the last five years, and had at least one relapse in the last three years. The link between monthly mean air pollutant levels and the relapses of MS in the participants was studied. RESULTS: Among the registered 160 participants, at least 150 had one attack during 2009 and 2012. Most air pollutants such as NO2, NO and CO are in high levels in the rainy season. Others like Pm10 and Nox are in high levels in the dry season. The correlation between NO2 levels of all markers of air quality and MS relapses (P=0.03, r=0.27) is weak. Best ARIMA model (p,d,q; 1,0,1) was determined between number of monthly relapses and living place, although this model was not significant (P=0.3) (AR; P=0.000, MA;P=0.4). CONCLUSIONS: Air pollutants might be regarded as a risk factor for MS relapse.