BACKGROUND AND OBJECTIVE: Previous research suggests an association of celiac disease (CD) with anorexia nervosa (AN), but data are mostly limited to case reports. We aimed to determine whether CD is associated with the diagnosis of AN.
METHODS: Register-based cohort and case-control study including women with CD (n = 17 959) and sex- and age-matched population-based controls (n = 89 379). CD (villous atrophy) was identified through the histopathology records of Sweden's 28 pathology departments. Inpatient and hospital-based outpatient records were used to identify AN. Hazard ratios for incident AN diagnosis were estimated by using stratified Cox regression with CD diagnosis as a time-dependent exposure variable. In the secondary analyses, we used conditional logistic regression to estimate odds ratios for being diagnosed with AN before CD.
RESULTS: Median age of CD diagnosis was 28 years. During 1 174 401 person-years of follow-up, 54 patients with CD were diagnosed with AN (27/100 000 person-years) compared with 180 matched controls (18/100 000 person-years). The hazard ratio for later AN was 1.46 (95% confidence interval [CI], 1.08-1.98) and 1.31 beyond the first year after CD diagnosis (95% CI, 0.95-1.81). A previous AN diagnosis was also associated with CD (odds ratio, 2.18; 95% CI, 1.45-3.29). Estimates remained largely unchanged when adjusted for socioeconomic characteristics and type 1 diabetes.
CONCLUSIONS: The bidirectional association between AN diagnosis and CD warrants attention in the initial assessment and follow-up of these conditions because underdiagnosis and misdiagnosis of these disorders likely cause protracted and unnecessary morbidity
