Table 1 Study population characteristics

Enrolling centre, n (%):

<0.0001

- Evelina London Children’s

21 (2.6%)

25 (18.1%)

17 (38.6%)

63 (6.4%)

Hospital, London, UK

- Great Ormond Street

0 (0%)

0 (0%)

15 (34.1%)

15 (1.5%)

Hospital, London, UK

- Anna Meyer Children's University Hospital, Florence, Italy

793 (97.4%)

113 (81.9%)

12 (27.3 %)

918 (92.1%)

Age in years, median (IQR)

5.5 (3.1-8.1)

6.9 (4.3-10.8)

4.7 (3.0-11.6)

5.8 (3.1-8.5)

<0.0001

Gender, n (%):

<0.0001

- Male

496 (60.9%)

85 (61.6%)

15 (34.1%)

596 (59.4%)

- Female

310 (38.1 %)

52 (37.7%)

29 (65.9 %)

391 (39.6%)

- Not known

8 (1%)

1 (0.7%)

0 (0%)

9 (0.9%)

Country of origin * , n (%):

<0.0001

- Asia

146 (17.9%)

19 (13.8%)

4 (9.1%)

169 (17%)

- Latin America

183 (22.5%)

24 (17.4%)

4 (9.1%)

211 (21.2%)

- Eastern Europe§

269 (33%)

57 (41.3%)

5 (11.4%)

331 (33.2%)

- Western Europe

36 (4.4%)

7 (5.1%)

3 (6.8 %)

46 (4.6%)

- Nord Africa

16 (2%)

1 (0.7%)

2 (4.5%)

19 (1.9%)

- Sub-Saharan Africa

151 (18.6%)

29 (21%)

25 (56.8 %)

205 (20.6%)

- Other

8 (1%)

0 (0%)

0 (0%)

8 (0.8%)

- Not known

5 (0.6%)

1 (0.7%)

1 (2.3%)

7 (0.7%)

Ethnic group, n (%):

<0.0001

- African

168 (20.7%)

30 (21.7%)

27 (61.4%)

225 (22.6%)

- Asiatic

146 (17.9%)

19 (13.8%)

4 (9.1%)

169 (17%)

- Caucasian

306 (37.6%)

64 (46.4%)

8 (18.2%)

378 (37.9%)

- Hispanic

183 (22.5%)

24 (17.4%)

4 (9.1%)

211 (21.2%)

- Other

6 (0.7%)

0 (0%)

0 (0%)

6 (0.6%)

- Not known

5 (0.6%)

1 (0.7%)

1 (2.2%)

7 (0.7%)

BCG, n (%):

0.109

- Yes

460 (56.5%)

89 (64.5%)

20 (45.5%)

569 (57.1%)

- No

244 (30.0%)

40 (29.0%)

19 (43.2%)

303 (30.4%)

- Not known

110 (13.5%)

9 (6.5%)

5 (11.4%)

124 (12.4%)

Risk factors for vitamin D

0.932

deficiency†, n (%):

- Yes

470 (57.7%)

74 (53.6%)

32 (72.7%)

576 (57.8%)

- No

344 (42.3%)

64 (46.4%)

12 (27.3%)

420 (42.2%)

Risk factors for TB

<0.0001

infection, n (%):

- Tb contact

92 (11.4%)

31 (22.5%)

27 (21.2%)

150 (15.1%)

- Travel to/immigrated from

695 (85.3%)

104 (75.4%)

10 (22.8%)

809 (80.1%)

TB endemic country

- Not known

27 (3.3%)

3 (2.1%)

7 (15.9%)

37 (3.7%)

IGRA, n (%):

<0.0001

- Positive

0 (0.0%)

45 (32.6%)

28 (63.6%)

73 (7.3%)

- Negative

792 (97.3%)

71 (51.4%)

7 (15.9%)

870 (87.3%)

- Not known

22 (2.7%)

22 (15.9%)

9 (20.5%)

53 (5.3%)

TST, n (%):

<0.0001

- Positive

0 (0.0%)

120 (87%)

32 (72.7%)

152 (15.3%)

- Negative

777 (95.5%)

10 (7.2%)

2 (4.5%)

789 (79.2%)

- Not known

37 (4.5%)

8 (5.8%)

10 (22.7%)

55 (55.2%)