title: Risk factors in multiple sclerosis: a population-based case-control study in Sicily. Background and methods.
abstract: Incidence of multiple sclerosis (MS) has steeply increased over time during the last 30 years in the city of Catania. We carried out a population-based case-control study to evaluate the possible role of both environmental and genetic factors. From 1975 to 2004 in Catania, 367 MS patients diagnosed according to the Poser's criteria had the onset of disease. A sample of MS patients was randomly selected from this incident cohort. Three controls matched by age and sex were randomly selected from the rosters of 14 GPs. Controls were proportionally selected according to the distribution by municipality of the target population using a multistage sampling methods. All cases and controls underwent a face-to-face interview to record information concerning environmental factors and a blood sample was taken for serological and genetic analysis. 164 MS patients (64 % women; mean age of 46.4 ± 10.7) and 481 controls (69 % women; mean age of 47.7 ± 14.8) were enrolled in the study. The distribution of the whole population and the selected controls by municipalities was similar. A blood sample was taken from 150 MS cases and from 337 controls. At the end of the enrolment, we obtained a representative sample of the MS cases and population controls avoiding possible selection bias. Participation rate was very high also concerning the collection of biological specimens.
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Nicoletti
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Messina
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Elisa
authors.initials: E
authors.lastname: Bruno
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Mostile
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Graziella
authors.initials: G
authors.lastname: Quattrocchi
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Loredana
authors.initials: L
authors.lastname: Raciti
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Dibilio
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Roberto
authors.initials: R
authors.lastname: Cappellani
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Emanuele
authors.initials: E
authors.lastname: D'Amico
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Giorgia
authors.initials: G
authors.lastname: Sciacca
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Salvatore
authors.initials: S
authors.lastname: Lo Fermo
authors.affiliation: Italian Society of General Medicine (SIMG)-Catania Municipality Section, Catania, Italy.
authors.forename: Vincenza
authors.initials: V
authors.lastname: Paradisi
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Patti
authors.affiliation: Department GF Ingrassia, Section of Neurosciences, University of Catania, Via Santa Sofia 78, 95123, Catania, Italy. m.zappia@unict.it.
authors.forename: Mario
authors.initials: M
authors.lastname: Zappia
mesh_terms: D000328:Adult; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D009103:Multiple Sclerosis / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics; D012307:Risk Factors; D012802:Sicily / Q000453:epidemiology; D011795:Surveys and Questionnaires; D055815:Young Adult
keywords: Case–control study; Epidemiology; Multiple sclerosis