title: Multiple Sclerosis in the Mount Etna region: possible role of volcanogenic trace elements.
abstract: BACKGROUND
  Trace elements have been hypothesised to be involved in the pathogenesis of Multiple Sclerosis and volcanic degassing is the major natural sources of trace elements. Both incidence of Multiple Sclerosis in Catania and volcanic activity of Mount Etna have been significantly increased during the last 30 years. Due to prevailing trade winds direction, volcanic gases from Etna summit craters are mostly blown towards the eastern and southern sectors of the volcano.
  
  
  OBJECTIVE
  To evaluate the possible association between Multiple Sclerosis and exposure to volcanogenic trace elements.
  
  
  METHODS
  We evaluated prevalence and incidence of Multiple Sclerosis in four communities (47,234 inhabitants) located in the eastern flank and in two communities (52,210 inhabitants) located in the western flank of Mount Etna, respectively the most and least exposed area to crater gas emissions.
  
  
  RESULTS
  A higher prevalence was found in the population of the eastern flank compared to the population of the western one (137.6/100,000 versus 94.3/100,000; p-value 0.04). We found a borderline significantly higher incidence risk during the incidence study period (1980-2009) in the population of the eastern flank 4.6/100,000 (95% CI 3.1-5.9), compared with the western population 3.2/100,000 (95% CI 2.4-4.2) with a RR of 1.41 (95% CI 0.97-2.05; p-value 0.06). Incidence risks have increased over the time in both populations reaching a peak of 6.4/100,000 in the eastern flank and of 4.4/100.000 in the western flank during 2000-2009.
  
  
  CONCLUSIONS
  We found a higher prevalence and incidence of Multiple Sclerosis among populations living in the eastern flank of Mount Etna. According to our data a possible role of TE cannot be ruled out as possible co-factor in the MS pathogenesis. However larger epidemiological study are needed to confirm this hypothesis.
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Nicoletti
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Bruno
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Nania
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Edoardo
authors.initials: E
authors.lastname: Cicero
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Messina
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Clara
authors.initials: C
authors.lastname: Chisari
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Josita
authors.initials: J
authors.lastname: Torrisi
authors.affiliation: Neurology Unit, Garibaldi Hospital, Catania, Italy.
authors.forename: Davide
authors.initials: D
authors.lastname: Maimone
authors.affiliation: Neurology Unit, Cannizzaro Hospital, Catania, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Marziolo
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Lo Fermo
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Patti
authors.affiliation: Istituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo, Catania, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Giammanco
authors.affiliation: Depatment G.F. Ingrassia Section of Neurosciences, University of Catania, Catania, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Zappia
mesh_terms: D000328:Adult; D017677:Age Distribution; D005260:Female; D006801:Humans; D015994:Incidence; D007558:Italy; D008297:Male; D009103:Multiple Sclerosis / Q000453:epidemiology* / Q000378:metabolism*; D015995:Prevalence; D017678:Sex Distribution; D014131:Trace Elements / Q000032:analysis*; D018707:Volcanic Eruptions / Q000032:analysis*
chemical_list: D014131:Trace Elements