High prevalence and increasing incidence of Addison's disease in western Norway

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.