Table 1

Characteristics of participants with and without LTBI and unadjusted prevalence ratios for the association with LTBI

IGRA  positive (n (%))IGRA negative (n (%))Prevalence ratio (95% CI)P values
Total2534 (27.7)6623 (72.3)
Diabetes (n=9157)
 No2296 (27.3)6105 (72.7)Referent0.012
 Yes238 (31.5)518 (68.5)1.15 (1.03 to 1.29)
Sex (n=9107)
 Male1406 (30.9)3149 (69.1)Referent<0.001
 Female1116 (24.5)3436 (75.5)0.79 (0.74 to 0.85)
Age group (years) (n=9152)
 16–25510 (22.6)1747 (77.4)Referent<0.001
 26–35887 (28.2)2258 (71.8)1.25 (1.14 to 1.37)
 36–45470 (33.1)949 (66.9)1.47 (1.32 to 1.63)
 >45666 (28.6)1665 (71.4)1.26 (1.14 to 1.40)
Country of birth (n=9131)
 Non-UK2279 (29.7)5385 (70.3)Referent<0.001
 UK245 (16.7)1222 (83.3)0.56 (0.50 to 0.63)
Ethnicity (n=8934)
 Indian1043 (27.8)2716 (72.3)Referent<0.001
 White233 (21.0)879 (79.1)0.76 (0.67 to 0.86)
 Black African403 (37.0)687 (63.0)1.33 (1.21 to 1.46)
 Mixed270 (30.9)603 (69.1)1.11 (1.00 to 1.25)
 Pakistani264 (30.1)614 (69.9)1.08 (0.97 to 1.21)
 Bangladeshi134 (19.3)561 (80.7)0.69 (0.59 to 0.82)
 Black Caribbean37 (16.8)183 (83.2)0.61 (0.45 to 0.82)
 Black Other/Chinese/Other78 (25.4)229 (74.6)0.92 (0.75 to 1.12)
Type of participant (n=9157)
 Contact1384 (29.6)3286 (70.4)Referent<0.001
 New entrant1150 (25.6)3337 (74.4)0.86 (0.81 to 0.92)
Previous BCG vaccination (n=7759)
 No394 (27.8)1024 (72.2)Referent0.65
 Yes1724 (27.2)4617 (72.8)0.98 (0.89 to 1.07)
Previous TB diagnosis (n=9012)
 No2321 (26.7)6368 (73.3)Referent<0.001
 Yes180 (55.7)143 (44.3)2.09 (1.88 to 2.31)
Previous contact with TB case (n=8833)
 No2080 (27.1)5599 (72.9)Referent0.01
 Yes355 (30.8)799 (69.2)1.14 (1.03 to 1.25)
HIV positive (n=8539)
 No2366 (27.9)6121 (72.1)Referent0.88
 Yes14 (26.9)38 (73.1)0·97 (0.62 to 1.51)
Other immunosuppression* (n=9150)
 No2483 (27.9)6425 (72.1)Referent0.007
 Yes49 (20.3)193 (79.8)0.73 (0.56 to 0.93)
Smoking (n=9125)
 No2038 (27.6)5352 (72.4)Referent0.61
 Yes489 (28.2)1246 (71.8)1.02 (0.94 to 1.11)
BMI (kg/m2) (n=8589)
 <18.5113 (26.3)317 (73.7)Referent0.38
 18.5–251155 (27.3)3069 (72.7)1.04 (0.88 to 1.23)
 ≥251122 (28.5)2813 (71.5)1.09 (0.92 to 1.28)
Any social risk factor† (n=9157)
 No2407 (27.6)6328 (72.4)Referent0.26
 Yes127 (30.1)295 (69.9)1.09 (0.94 to 1.27)
  • *Other immunosuppressive factors considered were history of using antitumour necrosis factor alpha or other immunosuppressive drugs, solid organ transplant, haematological malignancy, jejunoileal bypass, chronic renal failure or haemodialysis and gastrectomy.

  • †Social risk factors considered were current or past homelessness, imprisonment or problem drug use.

  • BMI, body mass index; IGRA, interferon gamma release assay; LTBI, latent tuberculosis infection; TB, tuberculosis.