In patients with OCD, most individual AD showed an increased comorbidity rate, but the association was strongest for Sjögren's syndrome (94% increase), celiac disease (76%), Guillain-Barré syndrome (71%), Crohn's disease (66%), Hashimoto's thyroiditis (59%), type 1 diabetes mellitus (56%), scarlet fever (52%), idiopathic thrombocytopenic purpura (51%), ulcerative colitis (41%) multiple sclerosis (41%), and psoriasis vulgaris (32%). Similarly, in TD/CTD, many individual AD showed an association but, due to modest statistical power for some of the rarest AD, this only reached statistical significance for Hashimoto's thyroiditis (106% increase), celiac disease (67%), scarlet fever (62%), type 1 diabetes mellitus (37%), and psoriasis vulgaris (33%). These results expand our previous knowledge on the subject – as previous studies had been limited by a range of methodological issues13 – and suggest that there is a clear association between both OCD and TD/CTD and AD in general, which is not limited to streptococcal-related conditions.
