Background: Earlier research has indicated a positive association between coeliac disease (CD) and some mental disorders. Studies on CD and depression have inconsistent findings and we know of no study of CD and the risk of bipolar disorder (BD).
Methods: We used Cox regression to investigate the risk of subsequent mood disorders (MD); depression and BD in 13,776 individuals with CD and 66,815 age- and sex-matched reference individuals in a general population-based cohort study in Sweden. We also studied the association between prior MD and CD through conditional logistic regression.
Results: CD was associated with an increased risk of subsequent depression (Hazard ratio (HR)=1.8; 95% CI=1.6-2.2; p<0.001, based on 181 positive events in individuals with CD and 529 positive events in reference individuals). CD was not associated with subsequent BD (HR=1.1; 95% CI=0.7-1.7; p=0.779, based on 22 and 99 positive events). Individuals with prior depression (OR=2.3; 95% CI=2.0-2.8; p<0.001) or prior BD (OR=1.7; 95% CI=1.2-2.3; p=0.001) were at increased risk of a subsequent diagnosis of CD.
Limitations: Study participants with CD and MD may have more severe disease than the average patient with these disorders since they were identified through a hospital-based register.
Conclusions: CD is positively associated with subsequent depression. The risk increase for CD in individuals with prior depression and BD may be due to screening for CD among those with MD.