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Table 2 Demographics of the unexposed individuals

From: High background rates of positive tuberculosis-specific interferon-γ release assays in a low prevalence region of UK: a surveillance study

   Unexposed, age-matched individuals
   TSpot positive n=13 TSpot negative n=136 Odds ratio Univariate P
   n % n %   
Age (years), median (range) 64 (45-87) 70 (25-93)   0.81
Male, n (%) 5 (38) 70 (52)   0.36
Ethnicity, n (%)       
  White Caucasian 13 (100) 136 (100)   
Country of birth       
  UK born 9 (69) 126 (93) 0.18 0.006
  Other 4 (31)† 10 (7.4)   
  Years since immigration, median (range) 43 (21-62) 52 (8-61)   
Ever visited a high prevalence country, n (%) 4 (31) 47 (35)   0.84
  Years since last visit, median (range) 8.5 (0-40) 5.5 (0-60)   
Ever resident in a high prevalence area >6/52, n (%) 2 (15) 27 (20)   0.64
Occupation: healthcare, prison, lab n (%)‡ 4 (31) 18 (13)   0.09
BCG (history or scar), n (%)       
  Yes 7 (54) 66 (49)   0.73
  No 4 (31) 44 (33)   
  Unknown 2 (15) 26 (19)   
Medical history, n (%)       
  Comorbidity known to be associated with TB§ 0 (0) 21 (16)   0.22
  Immunosuppresive medications 4 (31) 12 (9.2) 4.6 0.015
  Ever known to be exposed to TB 4 (31) 26 (19)   0.32
  Ever had treatment for tuberculosis 2 (15) 2 (1.5) 12 0.003
  1. † Germany (2), South Africa (1), Hong Kong (1).
  2. ‡ Percentages are those of those with valid data.
  3. § Diabetes mellitus (17), chronic renal failure (3), haematological malignancy (2), gastric surgery (1).
  4. Systemic steroids (12), methotrexate (4), hydroxychloroquine (2), anti-TNF alpha (2), sulfasalzine (1).