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Table 2 Distribution of age, gender and risk factors for tuberculosis (TB) in 525 household contacts of 176 adults with confirmed pulmonary TB according to infection categories at baseline Contact Investigation

From: Identification of subclinical tuberculosis in household contacts using exposure scores and contact investigations

 MissingTotal with available data N = 525TST−/QFT-1 N = 167TST+ or QFT + 1 N = 167TST+/QFT + 1 N = 113Subclinical TB2 at baseline N = 29
n (%)n (%)n (%)n (%)n (%)n (%)
Interview
 Gender (male)49 (9.3)193 (40.5)79 (47.3)61 (36.5)39 (34.5)14 (48.3)
 Age (years)350 (9.5)     
  < 5 38 (8.0)22 (13.2)8 (4.8)6 (5.4)2 (6.9)
 5–14 138 (29.1)41 (24.6)47 (28.1)38 (33.9)12 (41.4)
  > 14 299 (62.9)104 (62.3)112 (67.1)68 (60.7)15 (51.7)
Individual risk factors
 Diabetes mellitus49 (9.3)9 (1.9)2 (1.2)5 (3.0)1 (0.9)1 (3.4)
 Smoking49 (9.3)118 (24.8)35 (21.0)48 (28.7)27 (23.9)8 (27.6)
Tuberculosis Contact Score
 Mean (St.dev) 10.9 (2.3)10.4 (2.3)11.1 (2.3)11.6 (2.0)11.2 (1.8)
 Symptoms4 13 (2.7)5 (3.0)4 (2.4)3 (2.7)1 (3.4)
Environmental risk factors
 Crowding5 (mean, St.dev)55 (10.5)4.25 (2.04)4.41 (2.25)4.14 (1.98)4.18 (1.89)3.43 (1.53)
In-door pollution655 (10.5)     
 LPG 60 (11.4)14 (9.8)21 (14.2)17 (16.3)2 (7.4)
 Kerosene 15 (2.9)3 (2.1)4 (2.7)5 (4.8)1 (3.7)
 Wood + agri residue 329 (75.2)126 (88.1)123 (83.1)82 (78.8)24 (88.9)
Examination and tests
 Tuberculin Skin Test (TST)49 (9.3)  
 mm (median, range) 8.0 (34)6.0 (9)7.0 (34)14.0 (23)7.0 (12)
  ≥ 10 mm 152 (31.9)030 (18.0)113 (100)9 (31.0)
 Quantiferon (QFT)51 (9.7)  
 IU/mL (median, range) 0.56 (19.8)0.03 (3.2)1.44 (10.7)4.58 (9.6)1.36 (10.1)
  ≥ 0.35 IU/mL 266 (56.1)0137 (82.0)113 (100)16 (59.3)
Mtb specimen for culture32 (6.1)  
 2 of 2 samples harvested 471 (98.9)162 (97.9)167 (100)113 (100)29 (100)
 1 of 2 samples harvested 5 (1.1)5 (3.0)000
 Smear + 7 (1.5)2 (1.2)2 (1.2)2 (1.8)1 (3.4)
 Chest X-ray49 (9.3)  
 Abnormal, not TB 13 (2.7)4 (2.4)1 (0.6)7 (6.2)1 (3.4)
 Abnormal, TB 15 (3.2)3 (1.8)7 (4.2)3 (2.7)2 (6.9)
 BCG scar present96 (18.3)  
 Yes 221 (51.5)85 (55.6)76 (50.7)46 (46.0)14 (53.8)
BMI and BMIZ7
 BMI when aged ≥15 years. Mean (st.dev)29 (8.8)19.6 (3.19)19.30 (3.03)20.15 (3.72)19.25 (2.61)18.69 (2.13)
 BMIZ when aged< 15 years. Mean (st.dev)9 of 187−0.14 (1.70)− 0.48 (1.85)0.19 (1.33)−0.14 (1.91)− 0.15 (1.71)
  1. 1Tuberculin Skin Test (TST) was dichotomized around the cutoff 10 mm; ≥10 mm corresponding to TST+ and < 10 mm corresponding to TST-. Quantiferon (QFT) was dichotomized around the cutoff 0.35 IU/mL; ≥0.35 IU/mL corresponding to QFT+ and < 0.35 IU/mL corresponding to QFT-. Analysis limited to subjects with both test results. 2Subjects with growth of Mycobacterium tuberculosis (Mtb) in liquid culture of respiratory specimen. 3WHO based age categories.4 ≥ 1 of the following: cough > 2 wks, fever/night sweats, loss of weight/appetite, haemoptysis, chestpain. 5Number of household members divided on rooms in the house. 6By type of fuel: LPG, Kerosene, Wood + agricultural residue. 7Body Mass Index (BMI), Body Mass Index Z-score (BMIZ)