Table 3. Univariable analysis of time to TB episode; hazard ratios, 95% CI and P-values (nmax = 2679) - All TB cases (n = 52).
| Variable | Description | n (col %) | Rate/1000 pyrs | TB cases/pyrs | Unadjusted HR(95% CI) | P-value |
| TST response1 (mm) | <10≥ 10 | 867 (35)1591 (65) | 4.8911.71 | 9/184039/3332 | 12.37 (1.15–4.89) | 0.01 |
| TST response 1 (mm) | <55–910–14≥ 15 | 548 (22)319 (13)688 (28)903 (37) | 3.317.274.7516.49 | 4/11955/6457/144332/1889 | 12.18 (0.59–8.13)1.40 (0.41–4.79)4.92 (1.74–13.92) | 0.0002 |
| EC response2(SFC/million PBMC) | <20≥ 20 | 337 (35)615 (65) | 6.8513.56 | 5/73018/1327 | 11.98 (0.74–5.33) | 0.15 |
| EC response2(SFC/million PBMC) | <32≥ 32 | 408 (43)544 (58) | 6.8614.37 | 6/87517/1183 | 12.13 (0.84–5.41) | 0.09 |
| Gender | MaleFemale | 1420 (53)1259 (47) | 8.759.74 | 23/263029/2977 | 11.11 (0.65–1.93) | 0.70 |
| Age (years) | ≤1516–29≥ 30 | 1031 (38)897 (33)751 (28) | 2.7115.3011.54 | 6/221628/183018/1560 | 15.50 (2.28–13.29)4.18 (1.66–10.52) | <0.0001 |
| Duration of residence with index case3 (months) | <66–12>12 | 199 (7)173 (6)2293 (86) | 2.472.9710.33 | 1/4041/33650/4840 | 0.23 (0.03–1.67)0.27(0.04–1.96)1 | 0.05 |
| Eat with index case4 | NoLess than dailyDaily | 745 (28)660 (25)1273 (48) | 5.895.1213.28 | 9/15277/136636/2711 | 10.87 (0.33–2.35)2.33 (1.12–4.83) | 0.007 |
| Proximity to index case at night4 | Other houseSame houseSame roomSame bed | 430 (16)1764 (66)213 (8)271 (10) | 7.216.6418.0423.08 | 6/83225/37668/44413/563 | 11.00 (0.41–2.43)2.69 (0.93–7.75)3.43 (1.30–9.02) | 0.002 |
| Household size (number of people) | <1010–1415–19≥ 20 | 461 (17)700 (26)568 (21)950 (35) | 9.025.3916.838.02 | 9/9988/148419/112916/1995 | 10.59 (0.23–1.52)1.75 (0.79–3.86)0.86 (0.38–1.95) | 0.04 |
| Previous TB4 | NoYes | 2604 (97)74 (3) | 7.5074.47 | 41/546411/140 | 110.14 (5.21–19.74) | <0.0001 |
| Smoking (adults only; age>15 yrs, n = 1647) | NoYes | 1495 (91)152 (9) | 12.2627.64 | 38/30998/289 | 12.15 (1.00–4.60) | 0.07 |
| BCG vaccination5 | NoYes | 1182 (44)1482 (56) | 9.379.29 | 23/245529/3120 | 11.00 (0.58–1.73) | 0.99 |
| Findings at TB diagnosis of index cases: | ||||||
| Cavitation on CXR6 | 01–23–8 | 372 (15)1277 (53)760 (31) | 11.227.749.94 | 9/80221/271315/1509 | 10.67 (0.31–1.48)0.83 (0.36–1.89) | 0.61 |
| Number of zones on CXR 7 | 0–34–56 | 1856 (72)616 (24)92 (3) | 8.969.2215.81 | 35/390712/13013/190 | 11.03 (0.54–1.99)1.72 (0.53–5.60) | 0.70 |
| Cough duration of index case8 (weeks) | ≤23–45–8>8 | 230 (9)1022 (38)662 (25)760 (28) | 8.855.8511.8111.50 | 4/45213/222316/135518/1565 | 0.72 (0.23–2.20)1.38 (0.46–4.13)1.34 (0.46–3.97) | 0.24 |
1
n = 221 missing;
2
based on n = 952;
3
n = 14 missing;
4
n = 1 missing;
5
n = 15 missing;
6
n = 270 missing;
7
n = 115 missing (from 8 households);
8
n = 5 missing (from 1 household); pyrs = person years; HR = hazard ratio; CI = confidence interval; CXR = chest radiograph; col = column; nmax = maximum number.