Table 1.

Baseline characteristics of the 178 patients with B-cell precursor ALL and 178 matched controls born in Denmark during 1995–2008

B-cell precursor ALL patients (n = 178)Controls (n = 178)
n (%)n (%)
Age at diagnosis (y)
 1–392 (51.7)
 4–664 (36.0)
 7–922 (12.3)
Year of birth
 1995–199854 (30.3)54 (30.3)
 1999–200251 (28.7)51 (28.7)
 2003–200542 (23.6)42 (23.6)
 2006–200831 (17.4)31 (17.4)
Age at neonatal blood spot sampling (days)
 3–422 (12.4)18 (10.1)
 5–796 (53.9)115 (64.6)
 ≥836 (20.2)35 (19.7)
 Missing24 (13.5)10 (5.6)
Mean6.36.1
Sex
 Boys95 (53.4)95 (53.4)
 Girls83 (46.6)83 (46.6)
Birth order
 172 (40.5)72 (40.5)
 278 (43.8)78 (43.8)
 ≥328 (15.7)28 (15.7)
Birth weight (gram)
 <3,0008 (4.5)8 (4.5)
 3,000–3,49958 (32.6)55 (30.9)
 3,500–3,99972 (40.4)78 (43.8)
 4,000–4,49930 (16.9)31 (17.4)
 ≥4,50010 (5.6)6 (3.4)
Mean36583651
Gestational age (weeks)
 ≤375 (2.8)5 (2.8)
 38–3960 (33.7)61 (34.3)
 40–41101 (56.8)106 (59.5)
 ≥4212 (6.7)6 (3.4)
Mean39.739.8
Mode of delivery
 Vaginal162 (91.0)162 (91.0)
 Cesarean section16 (9.0)16 (9.0)
Maternal age at delivery (y)
 <2514 (7.9)28 (15.7)
 25–2967 (37.6)67 (37.7)
 30–3470 (39.3)62 (34.8)
 ≥3527 (15.2)21 (11.8)
Mean30.129.2
Maternal hospital contact due to infections during pregnancy
 Yes15 (8.4)8 (4.5)
 No163 (91.6)170 (95.5)
Maternal antimicrobial prescription during pregnancy
 Yes63 (35.4)64 (35.9)
 No115 (64.6)114 (64.1)