Multiple sclerosis incidence in the Faroe Islands 1986-2007

Abstract

Epidemiological studies of the isolated Faroese population in 1945 identified a high annual incidence of multiple sclerosis (MS) of 10/100,000. At the time, there was speculation that the disease was brought to the country by British occupation forces resident in the islands from 1940 to 1945. The objective of the current study is to determine the incidence of diagnosis of MS in the Faroe Islands during the period 1986-2007. All patients in the Faroe Islands diagnosed with MS from July 1, 1986 to July 1, 2007 are documented in the current longitudinal, prospective study. The diagnosis is based on clinical observation, magnetic resonance imaging scanning, cerebrospinal fluid tests, and visual evoked potential response testing. The incidence of MS during the period 1986-2007 is 4.5/100,000 annually. This is generally of the same order of magnitude as other research findings in Scandinavia and Iceland. The incidence of MS from 1986 to 2007 is about double the incidence in the Faroe Islands for the period from 1940 to 1986, calculated to be 2.7/100,000 annually. The observed incidence of MS in the Faroe Islands, where the population is genetically homogeneous and where the diet exposes the population to neuro-toxic contamination, is at the same level as found in other high-risk regions. The former detected epidemics of MS in Faroe Islands seems apparently to have leveled out and could not be recognized in the recent period covered by the present survey.