Table 1.
Baseline Characteristics of Household Contacts by Latent TB Infection Diagnosis (N = 109)
| Baseline Characteristic | Latent TB Infection |
P Value | |
|---|---|---|---|
| Negative (n = 51) | Positive (n = 58) | ||
| Demographic and socioeconomic | |||
| Age, yr, median (IQR) | 6.5 (3.5–10.0) | 6.2 (4.1–9.6) | 0.91 |
| Sex, F | 18 (35) | 23 (40) | 0.64 |
| Urban residence (vs. suburban) | 27 (53) | 27 (47) | 0.51 |
| Household education* | 0.40 | ||
| Secondary school or lower | 24 (47) | 32 (55) | |
| University or polytechnical | 27 (53) | 26 (45) | |
| Occupants, number/household, mean (SD) | 5.1 (1.4) | 5.8 (2.0) | 0.04 |
| Residential floor area, m2, median (IQR) | 60 (44–100) | 70 (47–120) | 0.96 |
| Occupant density, persons/50 m2, mean (SD) | 4.5 (3.08) | 4.8 (3.27) | 0.59 |
| Bedrooms, number/household, mean (SD) | 2.8 (1.4) | 2.8 (1.0) | 0.99 |
| Employed, proportion of adult household members, mean (SD) | 0.67 (0.27) | 0.65 (0.27) | 0.73 |
| Kitchen ventilation† | 0.67 | ||
| No ventilation | 0 | 2 (3.5) | |
| Passive ventilation | 24 (47) | 27 (47) | |
| Active ventilation | 27 (53) | 29 (50) | |
| Air conditioning installed | 46 (90) | 55 (95) | 0.36 |
| Clinical | |||
| BCG vaccination at birth, household contact | 48 (94) | 53 (91) | 0.58 |
| Exposed to index case with cavitary TB‡ | 11 (24) | 14 (25) | 0.91 |
| Smear grade of index case§ | 0.10 | ||
| Negative | 5 (11) | 1 (1.9) | |
| Scant (1–9 AFB in 100 HPF) | 9 (20) | 4 (7.7) | |
| 1+ (10–99 AFB in 100 HPF) | 19 (41) | 24 (46) | |
| 2+ (1–10 AFB in each of 50 HPFs) | 8 (17) | 16 (31) | |
| 3+ (>10 AFB in each of 20 HPFs) | 5 (11) | 7 (13) | |
| Percentage contact with index case, mean (SD)ǁ | 92 (19) | 91 (19) | 0.59 |
| Overweight or obese§ | 16 (31) | 20 (34) | 0.73 |
Definition of abbreviations: AFB = acid-fast bacilli; BCG = bacillus Calmette-Guérin vaccine; HPF = high-powered field (1,000×); index case = a patient with active tuberculosis to whom household contacts have been exposed; IQR = interquartile range; TB = tuberculosis.
Data are presented as n (%) unless otherwise indicated.
Highest education level attained by a household member.
Kitchen ventilation categories: no ventilation during cooking; passive ventilation through an open window or door to the outside; or active ventilation with a hood above the cooking stove or a fan in the kitchen window venting to the outside.
Missing data: chest radiograph not obtained or results not available for index cases of nine household contacts; AFB smear grade was not performed or unavailable for index cases of 11 household contacts.
As defined by the World Health Organization (30).
Percentage of days that household contact was living with index case in the 2 months before enrollment.