Coexistence of eating disorders and autoimmune diseases: Record linkage cohort study, UK.

OBJECTIVE: Recent research indicates that eating disorders (ED) are associated with type 1 diabetes and Crohn's disease. The aim of this study was to determine whether, in a hospitalized population, a range of autoimmune diseases (AIDs) occurred more often than expected in people with anorexia nervosa (AN) or bulimia nervosa (BN), and whether AIDs elevated the risk of ED. METHOD: Retrospective, record-linkage cohort study using national administrative statistical data on hospital care and mortality in England, 1999-2011. In people admitted when aged 10-44, cohorts of 8,700 females and 651 males with AN, and 4,783 females and 330 males with BN were constructed, along with a control cohort with the same age range. Results were expressed as risk ratios comparing each ED cohort with the control cohort. RESULTS: The overall rate ratio for an AID after admission for AN was 2.04 (95% confidence interval 1.81-2.28) in females, and 1.14 (0.37-2.67) in males; and, for BN, 1.83 (1.56-2.14) in females, and 4.41 (2.11-8.10) in males. Rate ratios for AN after admission for an AID were 3.34 (2.94-3.79) in females, 3.76 (2.06-6.53) in males; and those for BN were 2.57 (2.22-2.97) in females, and 3.10 (1.50-5.90) in males. There were significant associations between ED and several specific individual AIDs. DISCUSSION: Strong associations between ED and specific AIDs exist, although it is not possible from this study to determine if these are causal. Clinicians should be aware of the co-occurrence of these conditions. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2016; 49:663-672).