title: Diabetes-related tuberculosis in Denmark: effect of ethnicity, diabetes duration and year of diagnosis.
abstract: BACKGROUND
  The association between diabetes mellitus (DM) and tuberculosis (TB) has been established on the basis of cross-sectional studies; however, only a few longitudinal studies have been conducted, with inconsistent results.
  
  
  OBJECTIVE
  To study the effect of ethnicity and the presence and duration of DM on the risk of incident TB based on 15 years of follow-up of the entire Danish population.
  
  
  METHODS
  Using Poisson regression analysis, we estimated TB incidence in individuals with DM vs. those without DM by linking nationwide DM and TB registers to the National Civil Register at case level.
  
  
  RESULTS
  The TB rate ratio was 1.9 in individuals with DM compared to non-DM individuals, regardless of country of birth, with the exception of African-born individuals (rate ratio 0.5). The risk decreased drastically within the first 2 years after the diagnosis of DM; no association was found with longer durations of DM. The risk also decreased the later the year of DM diagnosis.
  
  
  CONCLUSIONS
  The study confirmed DM as a risk factor for TB, except in the case of African-born individuals. Other non-DM risk factors for TB could act as effect-modifiers on the DM-TB association. Implementing earlier DM diagnosis and improving metabolic control may reduce the risk of DM-related TB.
authors.affiliation: Clinical Epidemiology, Steno Diabetes Center, Gentofte, Denmark; Section for Health Services Research, Department of Public Health, Danish Research Centre for Migration, Ethnicity and Health, University of Copenhagen, Copenhagen, Denmark; Immunology and Microbiology Faculty of Medicine and Health Sciences, Department of International Health, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Z
authors.initials: Z
authors.lastname: Kamper-Jørgensen
authors.affiliation: Clinical Epidemiology, Steno Diabetes Center, Gentofte, Denmark.
authors.forename: B
authors.initials: B
authors.lastname: Carstensen
authors.affiliation: Section for Health Services Research, Department of Public Health, Danish Research Centre for Migration, Ethnicity and Health, University of Copenhagen, Copenhagen, Denmark; Department of Infectious Diseases and Department of Immigrant Medicine, Hvidovre University Hospital, Hvidovre, Denmark.
authors.forename: M
authors.initials: M
authors.lastname: Norredam
authors.affiliation: Immunology and Microbiology Faculty of Medicine and Health Sciences, Department of International Health, University of Copenhagen, Copenhagen, Denmark.
authors.forename: I C
authors.initials: IC
authors.lastname: Bygbjerg
authors.affiliation: Department of Infectious Disease Epidemiology, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: P H
authors.initials: PH
authors.lastname: Andersen
authors.affiliation: Clinical Epidemiology, Steno Diabetes Center, Gentofte, Denmark.
authors.forename: M E
authors.initials: ME
authors.lastname: Jørgensen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003718:Denmark / Q000453:epidemiology; D048909:Diabetes Complications / Q000453:epidemiology* / Q000208:ethnology; D003920:Diabetes Mellitus / Q000453:epidemiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D012307:Risk Factors; D013997:Time Factors; D014376:Tuberculosis / Q000453:epidemiology* / Q000208:ethnology / Q000209:etiology; D055815:Young Adult