A possible spatial and temporal cluster of multiple sclerosis in the town of Linguaglossa, Sicily

Abstract

We carried out an epidemiological survey to determine prevalence and incidence of multiple sclerosis in the little town of Linguaglossa in the Province of Catania. We calculated prevalence rate as point prevalence at 1 January 2001 and incidence during 1991-2000. We studied the frequency of multiple sclerosis in the community of Linguaglossa in a population of 5,422 inhabitants in the 2001 census. The primary sources for the case ascertainment were the general practitioners of Linguaglossa, the local Italian Multiple Sclerosis Association and the neurological departments, Multiple Sclerosis Centers and private neurologists of the province of Catania. We considered as prevalent and incident cases all patients who satisfied the Poser's diagnostic criteria. We detected 11 patients with multiple sclerosis who had had the onset of disease on prevalent day (P.D.). The onset-adjusted prevalence rate was 203/100,000 (95% CI 107-352). Prevalence was higher in women (247/100,000) than in men (154/100,000). From 1991 to 2000, 10 subjects with MS had clinical onset of disease. The mean annual incidence risk was 18.2/100,000 (C. I. 95 % 5.9-42.5). Conversely in the same population prevalence on 1 January 1991 was 37/100,000 while the onset adjusted annual incidence risk during the previous decade (1981-1991) was 3.6/100,000. Prevalence and incidence rates of MS during the last decade in the little town of Linguaglossa are higher than those found in the same area during the previous ten years and also than those reported in other Sicilian and Italian surveys suggesting a possible cluster of MS.

Incidence and prevalence of multiple sclerosis in Europe: a systematic review

“…Estimates as low as ≤ 20/100,000 were reported in some studies conducted in the 1980s [11-14], and also from more recent studies in Malta [15] and in ethnic minority populations of Norway and Bulgaria [16,17]. High estimates of ≥ 200/100,000 were reported in parts of Scotland and Northern Ireland and also within specific populations in Scandinavia [18,19] and Sicily [20]. Likewise, estimated annual incidence rates ranged widely from < 1/100,000 [11,15] to > 10/100,000 [20-22].…”

“…High estimates of ≥ 200/100,000 were reported in parts of Scotland and Northern Ireland and also within specific populations in Scandinavia [18,19] and Sicily [20]. Likewise, estimated annual incidence rates ranged widely from < 1/100,000 [11,15] to > 10/100,000 [20-22]. …”

“…Among the 28 reviewed studies from this region, nine were conducted in Sicily [13,20,31-37], seven in Northern Italy [38-44], seven in Sardinia [45-51], two in Central Italy [52,53], and one each in the south of Italy [54], San Marino [55] and Malta [15]. The Poser diagnostic criteria were used to identify cases in 25/28 of the studies.…”

A possible spatial and temporal cluster of multiple sclerosis in the town of Linguaglossa, Sicily: an update

“…Both prevalence and incidence of MS have still increased in the communities of Linguaglossa during the last quinquennium investigated. Incidence risk is significantly higher than that estimated in Catania town (capital of the province) [4,5]; furthermore, MS incidence estimated during the last 15 years was also significantly higher than incidence risk recorded in Linguaglossa during the decade 1981-1990 (3.6/100,000) [1], estimate, this latter, close to that reported in Catania during the same period [4,5].…”

“…For comparison, patients with MS were defined according to the Poser's Diagnostic criteria [6]. Background and methods have been extensively reported elsewhere [1].…”