Original Article Bone Mineral Density in Patients with Treated Addison’s Disease G. D. Braatvedt, M. Joyce, M. Evans, J. Clearwater and I. R. Reid Department of Medicine, University of Auckland, Private Bag, Auckland, New Zealand Abstract. Some studies have reported low bone mineral density (BMD) in patients with Addison’s disease, whereas others have found BMD to be normal. It is possible that over-replacement of corticosteroids and adrenal androgen deficiency may contribute to a reduction in BMD in these patients. The aims of this study were to examine BMD using dual-energy X-ray absorptiometry in patients with treated Addison’s disease at multiple skeletal sites and to investigate the relationships between these measurements and cortico- steroid dose. Nineteen men, 3 premenopausal and 7 postmenopausal women with Addison’s disease were studied and data from these patients were analyzed separately and as a group. The mean SEM age and duration of Addison’s disease of the men were 44 + 3.8 years and 15 + 2.2 years, in the premenopausal women 40 + 2 years and 5 + 2.4 years, and in the postmenopausal women 68 + 4 years and 20 + 5 years, respectively. Eight men were unexpectedly hypogonadal (serum testosterone <13 nmol/l). BMD was expressed as a percent of values in normal controls (n = 418) adjusted for age, sex, ethnic origin, menopausal status and body weight. In the whole group (n = 29), mean BMD of the patients with Addison’s disease was not different from normal at any site [mean (+ SEM) lumbar spine 99.5% + 2.9%; femoral neck 99.3% + 2.5%; Ward’s triangle 96.2% + 3.5%; trochanter 99.2% + 2.9%; radius 99.8% + 2.1%; total body 98.5% + 1.4%]. However, there was a wide range of bone densities, with some patients having a low BMD at multiple sites. Bone density was negatively correlated with current and cumulative corticosteroid dose per kilogram body weight and duration of Addison’s disease. In conclusion, BMD in patients with Addison’s disease is little different from normal, but may be lower in patients with disease of long duration and a high cumulative corticosteroid dose. Unexpected hypogonadism in men with Addison’s disease is common. Keywords: Addison’s disease; Bone mineral density; Steroids Introduction Patients with Cushing’s syndrome or those receiving pharmacologic doses of steroids are known to have significant osteopenia, especially in bones with a high trabecular content [1]. There is conflicting evidence, however, on the effects of physiologic replacement doses of steroids on bone mass. The bone mineral density (BMD) of patients with treated Addison’s disease has been variously reported as being low only in postmenopausal women [2,3], low only in men [4] or little different from normal in both men and women [5]. In the latter two studies [4,5], low BMD was defined as a value at either lumbar spine or hip >2 SD below that of the mean of normal control values. Overall mean BMD in the patient groups as a whole were not reported – assuming a normal distribution, some patients may have had BMD >2 SD above normal. Labeling patients as osteoporotic using this definition can thus be misleading regarding the overall effects of Addison’s disease on BMD. Furthermore, studies to date have not assessed BMD throughout the skeleton using total-body scans. Patients with Addison’s disease might have reduced BMD due to subtle over-replacement with corticoster- oids and/or a reduction in adrenal androgen production, especially in postmenopausal women. BMD might Osteoporos Int (1999) 10:435–440 ß 1999 International Osteoporosis Foundation and National Osteoporosis Foundation Osteoporosis International Correspondence and offprint requests to: Dr G. D. Braatvedt, Department of Medicine, University of Auckland, Auckland Hospital, Park Road, Auckland, New Zealand. Fax: +64 9 302 2101. e-mail: g.braatvedt@auckland.ac.nz