Table 4

Birth year adjusted analyses of the association between infant characteristics and childhood leukemia.


Sub-cohort
ALL
AML


No. (%)
No. (%)
HR
95% CI
No. (%)
HR
95% CI

Child gender







     female
4242 (49)
227 (41)
ref.
43 (49)
ref.
     male
4501 (51)
332 (59)
1.38
1.16–1.64
44 (51)
0.97
0.64–1.49
     missing
7 (0)
1 (0)


0 (0)


Birth weight







     Per 1 sd increase (per 581 grams)
8710
555
1.12
1.03–1.23
87
1.33
1.06–1.66
Birth weight category







     < 2496 g
406 (5)
29 (5)
1.49
0.96–2.30
2 (2)
0.86
0.19–3.94
     2496–3117 g
1746 (20)
83 (15)
ref.
10 (11)
ref.
     3118–3458 g
2192 (25)
117 (21)
1.13
0.84–1.51
23 (26)
1.85
0.88–3.91
     3459–3798 g
2142 (25)
152 (27)
1.48
1.12–1.95
20 (23)
1.65
0.77–3.54
     3799–4309 g
1796 (21)
137 (25)
1.59
1.20–2.11
27 (31)
2.65
1.27–5.49
     ≥ 4309 g
428 (5)
37 (7)
1.82
1.22–2.73
5 (6)
1.96
0.66–5.78
     missing
40 (0)
5 (1)


0 (0)


Size for gestational age*







     small
271 (3)
20 (4)
1.23
0.77–1.97
2 (2)
0.78
0.19–3.22
     average
5708 (72)
343 (67)
ref.
54 (65)
ref.
     large
1905 (24)
151 (29)
1.30
1.07–1.59
27 (33)
1.51
0.95–2.40
     missing
314 (4)
27 (5)


1 (1)


Gestational age category*







     <37 weeks
657 (8)
43 (8)
1.00
0.72–1.38
4 (5)
0.56
0.20–1.53
     37–42 weeks
6938 (88)
446 (86)
ref.
1 (1)
ref.
     >42 weeks
311 (4)
28 (5)
1.47
0.98–2.19
2 (2)
0.59
0.14–2.43
     missing
292 (4)
24 (4)


1 (1)


One minute Apgar score+







     0–7
1798 (23)
144 (29)
1.32
1.08–1.61
26 (33)
1.62
1.01–2.60
     >7
5884 (77)
359 (71)
ref.
53 (67)
ref.
     missing
336 (4)
34 (6)


4 (5)


Five minute Apgar score+







     0–7
275 (4)
14 (3)
0.77
0.44–1.33
4 (5)
1.47
0.53–4.08
     >7
7394 (96)
488 (97)
ref.
75 (95)
ref.
     missing
349 (4)
35 (7)


4 (5)


Assisted ventilation category







     any
79 (2)
5 (2)
0.93
0.37–2.34
0 (0)
ND
     none
4548 (98)
300 (98)
ref.
41 (100)


     missing
356 (7)
31 (9)


6 (13)


Congenital abnormality







     any
122 (1)
10 (2)
1.30
0.68–2.51
1 (1)
ND
     none
8100 (99)
505 (98)
ref.
81 (99)


     missing
528 (6)
45 (8)


5 (6)



*collected 1980–2004.

+collected 1981–2004.

collected 1989–2004.

ND = not determined

Johnson et al. BMC Pediatrics 2008 8:7   doi:10.1186/1471-2431-8-7