Clinical and epidemiological characteristics of individuals resistant to M. tuberculosis infection in a longitudinal TB household contact study in Kampala, Uganda

Table 6 Examination of “high risk” adults (age > 15) for key risk factors (N (%))

	PTST-	TSTC	TST+	Comparison across all 3 groups	Comparison of PTST- vs TSTC + TST+	Comparison of PTST- and TSTC vs TST+
*Characteristics of household*
Number of windows in house
Mean (SD)	3.48 (3.25)	3.10 (2.78)	1.93 (2.03)	< 0.0005	0.056	< 0.0005
Number of rooms in house
Mean (SD)	4.26 (4.06)	3.87 (3.23)	2.77 (2.42)	0.002	0.096	< 0.0005
# People in household/room
Mean (SD)	8.22 (7.30)	7.30 (5.88)	5.99 (3.93)	0.198	0.259	0.030
*Characteristics of index case*
Presence of cavitary disease
No	12 (54.5%)	28 (42.4%)	155 (38.4%)
Yes	10 (45.5%)	38 (57.6%)	249 (61.6%)	0.290	0.181	0.231
Baseline extent of disease on chest x-ray
Normal	3 (13.6%)	5 (7.6%)	13 (3.2%)
Minimal	5 (22.7%)	7 (10.6%)	44 (10.9%)
Moderate	7 (31.8%)	29 (43.9%)	145 (35.9%)
Advanced	7 (31.8%)	25 (37.9%)	202 (50.0%)	0.069	0.085	0.033

“High risk” defined as a score ≥ 6 out of 10 on risk score (based on Mandalakas et al. criteria).
PTST- = Persistently negative tuberculin skin test; TSTC = Tuberculin skin test converter; TST + = tuberculin skin test positive at baseline.