Autoimmune hypoadrenalism (Addisons disease) is a relatively rare condition; recent research has found the European prevalence to be up to 140 per million [Lovas & Husebye 2002]. It frequently occurs in association with other organ-specific autoimmune diseases, both endocrine and non-endocrine. Previous studies identified a considerable range in the prevalence of associated conditions and, because of the rarity of the disease, were often drawn from relatively small samples. In 2003 we conducted the largest international survey of autoimmune hypoadrenalism to date [N=613]. We asked patients to list all health conditions, including any apparently unrelated to their adrenal failure. Responses were compared to a well-matched control group [N=612]. There were some unexpected findings.
Autoimmune hypoadrenalism patients reported significant rates of asthma [13% compared to 7% of controls, P<<0.01], in addition to the anticipated associations of vitiligo, vitamin B12 deficiency, coeliac disease, alopecia and Sjogrens syndrome [P<<0.01]. Arthritic conditions such as rheumatoid arthritis and ankylosing spondylitis were reported at a similar frequency to controls; multiple sclerosis occurred at the same frequency [0.33%, consistent with Caucasian epidemiological studies eg Nielsen at al 2005]. There was a significant rate of primary biliary cirrhosis among hypoadrenalism patients [P=0.02]. The rate of thyroid disease associated with autoimmune adrenal failure was, at 49%, higher than that found in previous studies [Wilson 1998]. Type 1 diabetes, Type 2 diabetes and premature ovarian failure were reported at lower rates than found in previous studies but were statistically significant compared to controls [5%, 6%, 12%, P<<0.01]. Male testicular failure was reported at the same level as controls [2%].
These findings, drawn from the largest international survey of Addisons disease to date, have significant implications for managing autoimmune hypoadrenalism patients and screening them for the development of associated autoimmune conditions.