A case‐control study of the association between ulcerative colitis and hyperthyroidism in an Asian population

Summary Objective Ulcerative colitis (UC) is a chronic relapsing inflammatory disease with significant clinical diversity. However, the aetiology, pathogenesis and optimal treatment of UC remain unclear. The purpose of this case‐control study was to investigate the association between previously diagnosed hyperthyroidism and UC using a large population‐based data set in Taiwan. Methods The data for this population‐based case‐control study were retrieved from the Taiwan Longitudinal Health Insurance Database 2005. We included 2709 patients with UC as cases and 8127 sex‐ and age‐matched patients without UC as controls. A conditional logistic regression analysis was conducted to compute the odds ratio (OR) and corresponding 95% confidence interval (CI) for the association between UC and prior hyperthyroidism. Results We found that, in total, 327 of the 10 836 sampled patients (3.02%) had previously been diagnosed with hyperthyroidism. There was a higher proportion of prior hyperthyroidism among cases than controls (4.10% vs 2.66%, P