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Table 3 Risk factors for active tuberculosis in QuantiFERON®-TB Gold-positive schoolchildren (n = 938)

From: Risk factors for active tuberculosis in 938 QuantiFERON-positive schoolchildren in Mongolia: a community-based cross-sectional study

  

Proportion with active tuberculosis

Univariable analysis

Adjusted for age and sex only

Adjusted for age, sex and covariates with P < 0.2 on age- and sex-adjusted analysis(a)

   

Relative risk (95% CI)

P

Adjusted relative risk (95% CI)

P

Adjusted relative risk (95% CI)

P

Sex

Female

64/490 (13.1%)

1.00 (ref)

1.00 (ref)

1.00 (ref)

Male

65/448 (14.5%)

1.11 (0.81, 1.53)

0.52

1.13 (0.82, 1.55)

0.46

0.94 (0.66, 1.34)

0.74

Age

 

0.93 (0.84, 1.03)

0.14

0.92 (0.83, 1.02)

0.13

0.91 (0.81, 1.05)

0.13

Parental education(b)

University/polytechnic

10/127 (7.9%)

1.00 (ref)

1.00 (ref)

1.00 (ref)

Secondary school or lower

119/811 (14.7%)

1.86 (1.00, 3.46)

0.048

1.94 (1.04, 3.60)

0.04

1.03 (0.56, 1.89)

0.91

Type of residence

Centrally heated

9/167 (5.4%)

1.00 (ref)

1.00 (ref)

1.00 (ref)

Not centrally heated

56/373 (15.0%)

2.79 (1.41, 5.50)

0.003

2.80 (1.42, 5.52)

0.00

1.55 (0.73, 3.28)

0.26

Ger (Yurt)

64/398 (16.1%)

2.98 (1.52, 5.85)

0.002

3.03 (1.55, 5.96)

0.00

1.36 (0.62, 2.96)

0.48

Household income, per 100 US dollars(c)

0.94 (0.90, 0.99)

0.01

0.94 (0.90, 0.98)

0.01

0.98 (0.94, 1.02)

0.40

Home ownership

No

30/220 (13.6%)

1.00 (ref)

1.00 (ref)

Yes

99/718 (13.8%)

1.01 (0.69, 1.48)

0.95

1.00 (0.69, 1.47)

0.98

 

Number of people/room(c)

1.10 (1.02, 1.20)

0.02

1.11 (1.03, 1.21)

0.01

1.02 (0.93, 1.12)

0.64

Month of sampling

June–November

12/243 (4.9%)

1.00 (ref)

1.00 (ref)

1.00 (ref)

December–February

54/379 (14.2%)

2.89 (1.58, 5.28)

< 0.001

2.94 (1.61, 5.38)

< 0.001

2.53 (1.23, 5.19)

0.01

March–May

63/316 (19.9%)

4.04 (2.23, 7.31)

< 0.001

4.08 (2.26, 7.38)

< 0.001

3.31 (1.63, 6.74)

< 0.001

Number of smokers in household(d)

0

57/530 (10.8%)

1.00 (ref)

1.00 (ref)

1.00 (ref)

1 or more

72/408 (17.6%)

1.64 (1.19, 2.27)

0.003

1.66 (1.20, 2.26)

0.002

1.29 (0.92, 1.81)

0.13

Child actively smoking

No

128/936 (13.7%)

1.00 (ref)

1.00 (ref)

1.00 (ref)

Yes

1/2 (50.0%)

3.66 (0.91, 14.76)

0.07

3.84 (0.85, 17.44)

0.08

5.23 (2.70, 10.12)

< 0.001

BCG scar

Absent

27/193 (14.0%)

1.00 (ref)

1.00 (ref)

Present

102/745 (13.7%)

0.98 (0.66, 1.45)

0.91

0.96 (0.65, 1.43)

0.85

 

Body mass index, kg/m2

0.88 (0.82, 0.94)

< 0.001

0.88 (0.82, 0.95)

0.001

1.00 (0.89, 1.13)

0.95

Body fat, %(c)

0.95 (0.92, 0.98)

< 0.001

0.94 (0.91, 0.97)

< 0.001

0.95 (0.90, 1.00)

0.07

Household PTB contact

No

83/780 (10.6%)

1.00 (ref)

1.00 (ref)

1.00 (ref)

Yes

46/158 (29.1%)

2.74 (1.99, 3.76)

< 0.001

2.72 (1.98, 3.73)

< 0.001

2.40 (1.74, 3.30)

< 0.001

De-seasonalized serum 25(OH)D(c)

< 10 ng/ml, n (%)

27/281 (9.6%)

0.63 (0.42, 0.94)

0.02

0.65 (0.43, 0.98)

0.04

0.74 (0.49, 1.10)

0.13

≥10 ng/ml, n (%)

100/652 (15.3%)

1.00 (ref)

1.00 (ref)

1.00 (ref)

  1. Abbreviations: 25(OH) D, 25-hydroxyvitamin D; BCG, Bacille Calmette–Guérin vaccine; CI, confidence interval; PTB, pulmonary tuberculosis; QFT, QuantiFERON®-TB Gold; ref., referent category; US, United States
  2. anamely parental education, type of residence, income, number of people per room, month of sampling, presence vs. absence of indoor smokers in household, child actively smoking, body mass index, % body fat, household contact with PTB, de-seasonalized serum 25(OH) D level
  3. bhighest educational level attained by either parent
  4. cMissing values (income, 8 missing; number of people per room, 1 missing; body fat, 5 missing; 25OHD, 5 missing)
  5. dDefined as a household member other than the participating child smoking tobacco indoor