Osteoporosis in Eating Disorders: A Follow-Up Study of Patients with Anorexia and Bulimia Nervosa

Zipfel, Stephan
Seibel, Markus J.
Löwe, Bernd
Beumont, Peter J.
Kasperk, Christian
Herzog, Wolfgang

Departments of General Internal and Psychosomatic Medicine (S.Z., B.L., W.H.), and Endocrinology and Metabolism (M.J.S., C.K.), University of Heidelberg, 69115 Heidelberg, Germany; and Department of Psychological Medicine (P.J.B.), University of Sydney, New South Wales 2006, Australia

Received November 8, 2000. Accepted August 7, 2001.

Address all correspondence and requests for reprints to: Stephan Zipfel, M.D., Department of General Internal and Psychosomatic Medicine, University of Heidelberg, Bergheimer Strasse 58, 69115 Heidelberg, Germany. E-mail: [email protected].

This research was supported by grants from the Medical Faculty, University of Heidelberg (Project No. 161/1997).

Abbreviations: AN, Anorexia nervosa; BMD, bone mineral density; BMI, body mass index; BN, bulimia nervosa; CV, coefficient of variation; DPD, desoxypyridinoline; DSM-IV, Diagnostic and Statistical Manual of Mental Disorders, ed 4; DXA, dual energy x-ray absorptiometry; E, estrogen; ERT, E replacement therapy; OC, osteocalcin; Rec_AN, recovered AN; Rec_BN, recovered BN; TAP, total alkaline phosphatase.

Journal of Clinical Endocrinology & Metabolism 86(11):p 5227-5233, November 2001.

This study prospectively investigated the course of bone mineral density (BMD) in patients with anorexia nervosa (AN) and bulimia nervosa (BN) over a 3.6-yr follow-up period. From an initial sample of 47 female patients with an eating disorder (T1), 38 (n = 24 AN; n = 14 BN) were reassessed at follow-up (T2) (participation rate, 80.1%). For nonrecovered AN patients at T2, prevalence rates of osteopenia (−1.0 sd ≥ T-score > −2.5 sd) and osteoporosis (T-score ≤ −2.5 sd) at the lumbar spine were 54.2 and 20.8%, respectively. Due to an annual loss of lumbar spine BMD (−3.7 ± 4.9%) in the chronic AN patients and a slight but insignificant annual increase (0.7 ± 1.7%) for those who recovered, the difference in BMD between both outcome groups was more pronounced at follow-up (0.93 ± 0.13 vs. 1.14 ± 0.13 g/cm²; P < 0.01). Nonrecovered AN patients with binge eating/purging type showed a significantly reduced BMD compared with patients with the restricting type (0.87 ± 0.13 vs. 1.02 ± 0.08 g/cm²; P = 0.02). Both at baseline and follow-up, AN patients had increased rates of bone resorption, as measured by urinary desoxypyridinoline, compared with a control group (n = 42) (11.4 ± 4.4 vs. 10.4 ± 7.8, P < 0.001, vs. 5.6 ± 2.4 and 10.4 ± 7.8 nm/mm creatinine, P < 0.05, respectively). The subtype of AN and body mass index were best predictors for BMD at the lumbar spine at follow-up (R² = 0.576). With one exception, all bulimic patients had BMD and markers of bone turnover within the normal range. These results suggest that patients with chronic AN, particularly of the binge eating/purging type, are at high risk for osteoporosis and may need additional therapy to prevent bone loss.