title: Reduced incidence of Crohn's disease in systemic sclerosis: a nationwide population study.
abstract: BACKGROUND
  To date, there has been no studies to evaluate the incidence of Crohn's disease in systemic sclerosis patients. The goals of this study were to evaluate the incidence of Crohn's disease and its relationship with sex and age in patients with systemic sclerosis.
  
  
  METHODS
  We enrolled patients with systemic sclerosis and controls from Taiwan's Registry of Catastrophic Illness Database and National Health Insurance Research Database. Every systemic sclerosis patient was matched to at most three controls by sex, age, month and year of initial diagnosis of systemic sclerosis. The standardized incidence ratio (SIR) of Crohn's disease in systemic sclerosis patients, and 95% confidence interval (95% CI) were calculated. Cox hazard regression was used to calculate the hazard ratio (HR).
  
  
  RESULTS
  The study enrolled 2,829 patients with systemic sclerosis and 8,257 controls. Male and female patients with systemic sclerosis both had lower rates of incident Crohn's disease (SIR: 0.18, 95% CI = 0.05-0.62; SIR: 0.10, 95% CI = 0.05-0.21, respectively). The risk of incident Crohn's disease in systemic sclerosis was still lower than in controls when we stratified the patients according to their ages. In Cox hazard regression, the hazard rates of Crohn's disease were lower in systemic sclerosis patients after adjusting for genders and ages (HR: 0.12, 95% CI = 0.06-0.21, p < 0.001).
  
  
  CONCLUSIONS
  Systemic sclerosis is associated with decreased incidence of, irrespective of sex and age of the patients.
authors.affiliation: Graduate Institute of Clinical Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. 990331kmuh@gmail.com.|Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. 990331kmuh@gmail.com.
authors.forename: Chia-Chun
authors.initials: CC
authors.lastname: Tseng
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. jehsye@cc.kmu.edu.tw.|Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, Taiwan. jehsye@cc.kmu.edu.tw.|Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. jehsye@cc.kmu.edu.tw.
authors.forename: Jeng-Hsien
authors.initials: JH
authors.lastname: Yen
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. d10153@ms14.hinet.net.
authors.forename: Wen-Chan
authors.initials: WC
authors.lastname: Tsai
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. tsanteng@yahoo.com.tw.
authors.forename: Tsan-Teng
authors.initials: TT
authors.lastname: Ou
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. randymanwu@hotmail.com.
authors.forename: Cheng-Chin
authors.initials: CC
authors.lastname: Wu
authors.affiliation: Division of Rheumatology, Department of Internal Medicine, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan. hemidark@gmail.com.|Graduate Institute of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan. hemidark@gmail.com.
authors.forename: Wan-Yu
authors.initials: WY
authors.lastname: Sung
authors.affiliation: Division of Endocrinology and Metabolism, Department of Internal Medicine, Changhua Christian Hospital, Changhua, Taiwan. 146446@cch.org.tw.|Graduate Institute of Integrated Medicine, China Medical University, Taichung, Taiwan. 146446@cch.org.tw.
authors.forename: Ming-Chia
authors.initials: MC
authors.lastname: Hsieh
authors.affiliation: Department of Kinesiology, Health and Leisure Studies, National University of Kaohsiung, Kaohsiung, Taiwan. changsj1104@gmail.com.
authors.forename: Shun-Jen
authors.initials: SJ
authors.lastname: Chang
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003424:Crohn Disease / Q000175:diagnosis* / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance / Q000379:methods; D012042:Registries; D012595:Scleroderma, Systemic / Q000175:diagnosis* / Q000453:epidemiology*; D013624:Taiwan / Q000453:epidemiology; D055815:Young Adult