Objective: Estimates of the prevalence of Addison's disease in Caucasians have varied from 39 to 117 per million. We have carried out an epidemiological study to obtain a confident point prevalence estimate in the Norwegian population for the end of 1999, and to find out whether the incidence is changing.
Patients and methods: The patients were identified by a search through registers of 10 hospitals and consultant endocrinologists serving a population of 916 000. The completeness of the list was tested by a survey of general practitioners in one district, and by the member list of the local Addison Association in another district.
Results: We identified 128 patients with Addison's disease (59 men and 69 women), yielding a prevalence of 140 per million. Recorded mean incidence in the past decade was 0.62 per 100,000 per year. Fifty-one patients (40%) had concomitant endocrine diseases. The aetiology was almost exclusively idiopathic or autoimmune.
Conclusions: We found a higher prevalence of Addison's disease in western Norway than has previously been reported anywhere. Our findings support the hypothesis of a rising incidence of autoimmune adrenal insufficiency.