Table 1 Characteristics of household contacts, index tuberculosis cases and study dwellings according to the tuberculin skin test (TST) in contacts at study completion (8–12 weeks after enrollment)
Variable | All (N = 838) | TST-positive at baseline (n = 523) | TST converters (n = 62) | OR 95% CI | P + | TST-negative (n = 253) | OR 95% CI | P ++ |
|---|---|---|---|---|---|---|---|---|
Contact Factors | ||||||||
Age (per 10 years) | 20 [10–39] | 22 [12–41] | 15 [10–39] | 0.98 (0.76–1.01) | 0.06 | 18 [8–34] | 1.01 (0.90–1.15) | 0.77 |
Gender | 0.15 | 0.07 | ||||||
Male | 365 (44) | 231 (44) | 21 (34) | Ref. | 113 (45) | Ref. | ||
Female | 473 (56) | 292 (56) | 41 (66) | 1.38 (0.89–2.14) | 140 (55) | 1.63 (0.96–2.78) | ||
BCG scar | 0.18 | 0.09 | ||||||
No/ uncertain | 152 (18) | 98 (18) | 8 (13) | Ref | 46 (19) | Ref | ||
Yes | 686 (82) | 425 (81) | 54 (87) | 1.61 (0.80–3.24) | 207 (82) | 1.99 (0.89–4.48) | ||
Other TB contacta | 0.01 | 0.92 | ||||||
No | 665 (80) | 389 (75) | 56 (90) | Ref | 220 (87) | Ref | ||
Yes | 166 (20) | 127 (25) | 6 (10) | 0.38 (0.18–0.80) | 33 (13) | 0.94 (0.40–2.25) | ||
Index factors | ||||||||
Age (years) | 36 [23–42] | 34 [23–44] | 32 [22–39] | 0.99 (0.96–1.01) | 0.39 | 37 [27–42] | 0.98 (0.95–1.00) | 0.08 |
Cough duration (weeks) | 8 [4–16] | 8 [4–16] | 8 [4–12] | 0.96 (0.92–1.02) | 0.17 | 8 [4–16] | 0.97 (0.94–1.00) | 0.09 |
VACS | 8 [5–9] | 8 [5–9] | 9 [8–10] | 1.02 (0.89–1.17) | 0.74 | 5 [3–8.5] | 1.24 (1.08–1.42) | 0.003 |
LCQ | 12 [10–16] | 11 [10–14] | 12 [10–15] | 0.97 (0.87–1.07) | 0.51 | 13 [11–17] | 0.87 (0.79–0.97) | 0.01 |
Extent of disease on chest radiograph | ||||||||
Normal/Minimal | 49 (6) | 22 (4) | 11 (18) | Ref. | 0.15 | 16 (6) | Ref. | 0.66 |
Moderate | 406 (49) | 235 (46) | 31 (50) | 0.50 (0.15–1.63) | 140 (56) | 0.58 (0.14–2.08) | ||
Advanced | 371 (45) | 257 (50) | 20 (32) | 0.32 (0.10–1.06) | 94 (38) | 0.55 (0.14–2.17) | ||
Cavitation | ||||||||
No | 211 (26) | 102 (20) | 22 (35) | Ref | 87 (35) | Ref | ||
Yes | 615 (74) | 412 (80) | 40 (65) | 0.51 (0.24–1.11) | 0.09 | 163 (65) | 1.10 (0.50, 2.41) | 0.81 |
Environmental Factors | ||||||||
Own residence | 0.06 | 0.17 | ||||||
No | 115(14) | 98 (19) | 2 (3) | Ref | 15 (6) | Ref | ||
Yes | 723 (86) | 425 (81) | 60 (97) | 4.22 (0.96–18.6) | 238 (94) | 2.44 (0.69-8.61) | ||
Sleep in same room as index | 0.34 | 0.004 | ||||||
No | 302 (36) | 170 (33) | 16 (26) | Ref | 116 (46) | Ref | ||
Yes | 536 (64) | 353 (67) | 46 (74) | 1.42 (0.59–3.4) | 137 (54) | 1.35 (1.45-7.35) | ||
Contact time with index (hours/ day) | 0.31 | 0.04 | ||||||
≤ 6 h | 255 (31) | 142 (27) | 16 (26) | Ref | 97 (38) | Ref | ||
> 6 h | 578 (69) | 376 (73) | 46 (74) | 1.31 (0.78–2.20) | 156 (62) | 1.83 (1.02–3.27) | ||