title: Erythema nodosum and the risk of tuberculosis in a high incidence setting.
abstract: This study estimates the erythema nodosum (EN) incidence in a tuberculosis (TB) endemic setting and evaluates the likelihood of a subsequent TB diagnosis among individuals withMycobacterium tuberculosisinfection (MTI) with or without EN.
  
  
  
  We estimated EN incidence rates (IRs) in East Greenland in 2010-2011 and conducted a cohort study following all individuals who tested positive for MTI from 1 January 2010 until 31 December 2012. A personal identifier allowed individual follow-up in the mandatory TB register. MTI was defined by a positive interferon-gamma release assay. TB incidence rate ratios (IRRs) among participants with or without EN were estimated with the Cox proportional hazard model.
  
  
  
  We identified 38 EN cases corresponding to an IR of 500/100,000 inhabitants/year. All cases were among individuals with MTI. The EN IR was 11.79 (95% CI 5.73-24.27) times higher for BCG-unvaccinated compared with BCG-vaccinated individuals. The TB IRR was 25 (95% CI 11-60) within 1 month of EN compared to individuals without EN.
  
  
  
  This study documents a high EN incidence in a TB endemic region. EN occurred only in individuals with MTI, and predominantly among BCG-unvaccinated individuals. EN was significantly associated with a TB diagnosis within 1 month of diagnosis.
authors: Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.|International Reference Laboratory of Mycobacteriology, Statens Serum Institut, Copenhagen, Denmark.|Greenland's Center of Health Research, Nuuk, Greenland.|Institute of Clinical Medicine, University of Southern Denmark, Odense, Denmark; kabm@ssi.dk.
authors: Karen
authors: K
authors: Bjorn-Mortensen
authors: Department of Internal Medicine, Queen Ingrid's Hospital, Nuuk, Greenland.
authors: Karin
authors: K
authors: Ladefoged
authors: Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.
authors: Jacob
authors: J
authors: Simonsen
authors: Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.
authors: Sascha W
authors: SW
authors: Michelsen
authors: Tasiilaq Hospital, Tasiilaq, Greenland.
authors: Hans Christian F
authors: HC
authors: Sørensen
authors: Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.
authors: Anders
authors: A
authors: Koch
authors: International Reference Laboratory of Mycobacteriology, Statens Serum Institut, Copenhagen, Denmark.
authors: Troels
authors: T
authors: Lillebaek
authors: Institute of Clinical Medicine, University of Southern Denmark, Odense, Denmark.|Department of Infectious Diseases, Copenhagen University Hospital, Copenhagen, Denmark.
authors: Aase Bengaard
authors: AB
authors: Andersen
authors: Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark.
authors: Bolette
authors: B
authors: Soborg
mesh_terms: D000328:Adult; D001500:BCG Vaccine; D015984:Causality; D015331:Cohort Studies; D004893:Erythema Nodosum / Q000175:diagnosis* / Q000453:epidemiology; D005260:Female; D006116:Greenland; D006801:Humans; D015994:Incidence; D059425:Interferon-gamma Release Tests; D008297:Male; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification*; D012307:Risk Factors; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis; D055815:Young Adult
chemical_list: D001500:BCG Vaccine
keywords: Erythema Nodosum; Greenland; Tuberculosis; interferon gamma release assay; mycobacterium tuberculosis