Myasthenia gravis incidence in a general North Atlantic isolated population

There are no previous studies undertaken about myasthenia gravis in the Faroe Islands. The aim of this study was to establish the incidence of onset of this disease in the Faroese population.

Patients were ascertained and registered prospectively from 1986 to 2013 when they were examined at the Neurological Clinic of the Faroese National Hospital or at a private neurological practice, which constitutes all the available neurological services in the Faroe Islands.

Twelve new diagnoses were made over a 27-year period, providing an incidence density rate of 9.4 per million person-years (95% confidence limit 4.9-16.5). At presentation, nine of 12 patients had generalized myasthenia gravis and two patients had pure ocular disease, and in one patient, the symptoms were restricted to the bulbo-facial muscles. The sex ratio was 2:1, F/M. In nine of the cases, a positive result of acetylcholine receptor antibody assay was documented. In all patients, there was a beneficial response to anticholinesterase administration.

The result yielded no strong evidence of a difference in incidence between that found in the Faroe Islands and those in most European studies, apart from recent studies from London, UK; Norway; Spain, and Italy in which incidences from 21 to 30 per million person-years had been reported.