title: The epidemiologic relationship between tuberculosis and non-tuberculous mycobacterial disease: a systematic review.
abstract: METHODS
  Tuberculosis (TB) rates are decreasing in many areas, while non-tuberculous mycobacteria (NTM) infection rates are increasing. The relationship between the epidemiology of TB and NTM infections is not well understood.
  
  
  OBJECTIVE
  To understand the epidemiologic relationship between TB and NTM disease worldwide.
  
  
  METHODS
  A systematic review of Medline (1946-2014) was conducted to identify studies that reported temporal trends in NTM disease incidence. TB rates for each geographic area included were then retrieved. Linear regression models were fitted to calculate slopes describing changes over time.
  
  
  RESULTS
  There were 22 studies reporting trends in rates of NTM disease, representing 16 geographic areas over four continents: 75% of areas had climbing incidence rates, while 12.5% had stable rates and 12.5% had declining rates. Most studies (81%) showed declining TB incidence rates. The proportion of incident mycobacterial disease caused by NTM was shown to be rising in almost every geographic area (94%).
  
  
  CONCLUSIONS
  We found an increase in the proportion of mycobacterial disease caused by NTM in many parts of the world due to a simultaneous reduction in TB and increase in NTM disease. Research into the interaction between mycobacterial infections may help explain this inverse relationship.
authors.affiliation: Joint Division of Respirology, Department of Medicine, University Health Network and Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: S K
authors.initials: SK
authors.lastname: Brode
authors.affiliation: Division of Mycobacterial and Respiratory Infections, National Jewish Health, Denver, Colorado, USA.
authors.forename: C L
authors.initials: CL
authors.lastname: Daley
authors.affiliation: Joint Division of Respirology, Department of Medicine, University Health Network and Mount Sinai Hospital, Toronto, Ontario, Canada.
authors.forename: T K
authors.initials: TK
authors.lastname: Marras
mesh_terms: D014943:Global Health / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D016014:Linear Models; D009165:Mycobacterium Infections, Nontuberculous / Q000453:epidemiology*; D014376:Tuberculosis / Q000453:epidemiology*