@article {Krishna1900476, author = {Mamidipudi Thirumala Krishna and Anuradhaa Subramanian and Nicola J. Adderley and Dawit Zemedikun and Georgios V. Gkoutos and Krishnarajah Nirantharakumar}, title = {Allergic Diseases and Long Term Risk of Autoimmune Disorders: longitudinal cohort study and cluster analysis}, elocation-id = {1900476}, year = {2019}, doi = {10.1183/13993003.00476-2019}, publisher = {European Respiratory Society}, abstract = {Background The association between allergic diseases (ADs) and autoimmune disorders (AIDs) is not well established.Objective To determine incidence rates of AIDs in allergic rhinitis/conjunctivitis (ARC), atopic eczema (AE) and asthma, and investigate for co-occurring patterns.Methods Design: Retrospective cohort study (1990{\textendash}2018) employing {\textquotedblleft}The Health Improvement Network{\textquotedblright} (UK primary care database).Exposure group: ARC, AE and asthma - all ages.Controls: For each exposed patient, up to 2 randomly selected age- and gender-matched controls with no documented AD.Adjusted incidence rate ratios (aIRRs) were calculated using Poisson regression. A cross-sectional study was also conducted employing Association Rule Mining (ARM) to investigate disease clusters.Results 782 320, 1 393 570 and 1 049 868 patients with ARC, AE and asthma, respectively, were included. aIRRs of systemic lupus erythematosus (SLE), Sjogren{\textquoteright}s syndrome (SS), vitiligo, rheumatoid arthritis (RA), psoriasis, pernicious anaemia, inflammatory bowel disease (IBD), coeliac disease (CD) and autoimmune thyroid disease were uniformly higher in the 3 ADs compared to controls. Specifically, aIRRs of SLE (1.45) and SS (1.88) were higher in ARC; SLE (1.44), SS (1.61) and myasthenia (1.56) higher in asthma; SLE (1.86), SS (1.48), vitiligo (1.54) and psoriasis (2.41) higher in AE.There was no significant effect of the 3 ADs on multiple sclerosis and ARC and AE on myasthenia.ARM: ADs clustered with multiple AIDs. Three age- and gender-related clusters were identified, with relatively complex pattern in females >=55 years.Conclusion The long-term risk of AIDs are significantly higher in patients with ADs. ADs and AIDs show age- and gender-related clustering patterns.FootnotesThis manuscript has recently been accepted for publication in the European Respiratory Journal. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJ online. Please open or download the PDF to view this article.Conflict of interest: Dr. Subramanian has nothing to disclose.Conflict of interest: Dr. Adderley has nothing to disclose.Conflict of interest: Mr. Zemedikun has nothing to disclose.Conflict of interest: Dr. Gkoutos has nothing to disclose.Conflict of interest: Dr. Nirantharakumar reports grants from NIHR, grants from MRC , grants from Diabetes UK, grants from AstraZeneca, personal fees from MSD, personal fees from Sanofi, personal fees from BI, outside the submitted work.Conflict of interest: Dr. Thirumala Krishna reports other from Thermo Fisher, other from ALK Abello, GSK, Mylan, Abbott, Allergy Therapeutics,Nutricia Danone and Biodiagnostics}, issn = {0903-1936}, URL = {https://erj.ersjournals.com/content/early/2019/08/07/13993003.00476-2019}, eprint = {https://erj.ersjournals.com/content/early/2019/08/07/13993003.00476-2019.full.pdf}, journal = {European Respiratory Journal} }