Contributions
Abstract: P490
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 17 Environmental factors
Background: Triggers of multiple sclerosis (MS) relapses are essentially unknown. Relapses´ incidence varies across seasons, suggesting a possible role of season-dependent factors such as ambient air pollution. Relatively few studies have investigated these hypotheses, but the role of ambient air pollution is of growing interest in neurological diseases etiology. A recent study from our group observed an increased risk of relapses with PM10 exposure for the 3 days preceding relapse onset in cold season.
Methods: We conducted a time-stratified case-crossover study to further explore the short-term associations between pollutants (e.g., NO2, C6H6, O3, and CO, initially modelled separately) and the odds of MS relapses occurrence. Our study population consists of 473 MS patients experiencing relapses and living in Strasbourg area (France) who experienced 2,045 relapses (2000-2009). Relative to the case (relapse) day, control days were chosen ±35 days. We performed a conditional logistic regression coupled with a distributed-lag model (considering lags 0-3) using the 'dlnm' R package, stratified by season (hot and cold), and adjusted on daily air pollutants concentrations, maximum temperature, maximum relative humidity, maximum atmospheric pressure, pollen count, influenza-like epidemics, and holidays.
Results: Interquartile range increases in PM10 and NO2 (lags 0-3) were associated with MS relapse incidence (ORPM10=1.06, 95%CI: [1.02-1.11] and ORNO2=1.07, 95%CI: [1.02-1.12], respectively) during cold months (i.e., October to March). We also observed an association with O3 and MS relapse incidence during hot months (ORO3=1.17, 95%CI: [1.09-1.26]). C6H6 and CO were not significantly related to MS relapse incidence (ORC6H6=1.05, 95%CI: [1.00-1.09] and ORCO=1.02, 95%CI: [0.97-1.07], respectively).
Conclusion: We found significant associations between air pollutants (e.g., NO2, PM10 and O3) exposure and occurrence of MS relapses using a case-crossover study, relevant to studies examining rare outcomes. Strengths of our study include a precise spatio-temporal exposure model and a clinically-diagnosed outcome from an exhaustive MS registry.
Disclosure:
Maxime Jeanjean was funded by EHESP French School of Public Health for the submitted work.
Maxime Jeanjean and Dr Bind were supported by the Office Of The Director, National Institutes Of Health, under Award Number DP5OD021412. The content is solely the responsibility of the authors, and does not necessarily represent the official views of the National Institutes of Health.
Jonathan Roux has no disclosure to report.
Dr de Sèze received personal fees as speaker or consultant from Biogen, Merck Serono, Bayer, LFB, Sanofi-aventis, Teva, Genzyme, Almiral, Alergan outside the submitted work.
Dr Ongagna has no disclosure to report.
Dr Bard has no disclosure to report.
Dr Leray reports personal fees as speaker or consultant from Novartis and Sanofi Genzyme, outside the submitted work, and travel grants from Novartis and Roche SAS. Sources of funding in the last year came from the French ARSEP Foundation, the French National Security Agency of Medicines and Health Products, the EDMUS Foundation, and donation from Roche SAS.
Abstract: P490
Type: Poster
Abstract Category: Pathology and pathogenesis of MS - 17 Environmental factors
Background: Triggers of multiple sclerosis (MS) relapses are essentially unknown. Relapses´ incidence varies across seasons, suggesting a possible role of season-dependent factors such as ambient air pollution. Relatively few studies have investigated these hypotheses, but the role of ambient air pollution is of growing interest in neurological diseases etiology. A recent study from our group observed an increased risk of relapses with PM10 exposure for the 3 days preceding relapse onset in cold season.
Methods: We conducted a time-stratified case-crossover study to further explore the short-term associations between pollutants (e.g., NO2, C6H6, O3, and CO, initially modelled separately) and the odds of MS relapses occurrence. Our study population consists of 473 MS patients experiencing relapses and living in Strasbourg area (France) who experienced 2,045 relapses (2000-2009). Relative to the case (relapse) day, control days were chosen ±35 days. We performed a conditional logistic regression coupled with a distributed-lag model (considering lags 0-3) using the 'dlnm' R package, stratified by season (hot and cold), and adjusted on daily air pollutants concentrations, maximum temperature, maximum relative humidity, maximum atmospheric pressure, pollen count, influenza-like epidemics, and holidays.
Results: Interquartile range increases in PM10 and NO2 (lags 0-3) were associated with MS relapse incidence (ORPM10=1.06, 95%CI: [1.02-1.11] and ORNO2=1.07, 95%CI: [1.02-1.12], respectively) during cold months (i.e., October to March). We also observed an association with O3 and MS relapse incidence during hot months (ORO3=1.17, 95%CI: [1.09-1.26]). C6H6 and CO were not significantly related to MS relapse incidence (ORC6H6=1.05, 95%CI: [1.00-1.09] and ORCO=1.02, 95%CI: [0.97-1.07], respectively).
Conclusion: We found significant associations between air pollutants (e.g., NO2, PM10 and O3) exposure and occurrence of MS relapses using a case-crossover study, relevant to studies examining rare outcomes. Strengths of our study include a precise spatio-temporal exposure model and a clinically-diagnosed outcome from an exhaustive MS registry.
Disclosure:
Maxime Jeanjean was funded by EHESP French School of Public Health for the submitted work.
Maxime Jeanjean and Dr Bind were supported by the Office Of The Director, National Institutes Of Health, under Award Number DP5OD021412. The content is solely the responsibility of the authors, and does not necessarily represent the official views of the National Institutes of Health.
Jonathan Roux has no disclosure to report.
Dr de Sèze received personal fees as speaker or consultant from Biogen, Merck Serono, Bayer, LFB, Sanofi-aventis, Teva, Genzyme, Almiral, Alergan outside the submitted work.
Dr Ongagna has no disclosure to report.
Dr Bard has no disclosure to report.
Dr Leray reports personal fees as speaker or consultant from Novartis and Sanofi Genzyme, outside the submitted work, and travel grants from Novartis and Roche SAS. Sources of funding in the last year came from the French ARSEP Foundation, the French National Security Agency of Medicines and Health Products, the EDMUS Foundation, and donation from Roche SAS.