Analysis of the 'epidemic' of multiple sclerosis in the Faroe Islands. I. Clinical and epidemiological aspects

The claim has been made that British troops introduced multiple sclerosis (MS), a transmissible disease, into the Faroe Islands during World War II, causing a three-tier epidemic which resulted in the appearance of 32 cases from 1943 until 1973. Assumptions underlying this hypothesis include the belief that the disease was absent from the Faroe Islands before 1940, the view that ascertainment of cases was complete and that Faroese patients who had either been born in Denmark or had been away from the Islands for 3 or more years before the onset of the disease had to be excluded. All the calculations were based on the presumed date of appearance of the first symptoms of MS. We reject the hypotheses of an epidemic and of the transmissibility of MS for several reasons. The most important one is that the date of onset of illness bears no relationship to the probable date of acquisition, which is widely believed to occur between the ages of 5 and 15 years. The criteria for exclusion of cases are arbitrary and instead of the accepted 32 cases, we believe that 42 cases should be counted in all analyses, including at least 2 with onset of illness before 1940. Only 15 of these 42 were in the age range 5-14 years during the British occupation. We cannot accept the statement that the disease was unknown in the Faroes before 1940 and believe that case ascertainment was incomplete in the Islands, which share close geographic, ethnic, and environmental similarities with other North Sea countries of high MS incidence. The theory of transmission is unconvincing and the characteristics of the putative agent unrealistic. The extremely high incidence of disease, which has statistical significance, is based on a very small number of cases in a very small population, and is of very doubtful biological significance.