Table 1.

Demographic characteristics of cases and controls in the Australian Study of causes of acute lymphoblastic leukemia in children, 2003–2007

CasesControls
N with child genotype392535
Variablen (%)n (%)
Sex
 Male176 (44.9)252 (47.1)
 Female216 (55.1)283 (52.9)
Age group
 0–1.935 (8.9)43 (8.0)
 2–4.9178 (45.4)239 (44.7)
 5–9.9111 (28.3)182 (34.0)
 10–14.968 (17.3)71 (13.3)
State of residence
 NSW/ACT123 (31.4)164 (30.7)
 Victoria/Tasmania117 (29.8)156 (29.2)
 SA/NT43 (11.0)48 (9.0)
 WA40 (10.2)61 (11.4)
 Queensland69 (17.6)106 (19.8)
Birth order
 1186 (47.4)220 (41.1)
 2120 (30.6)181 (33.8)
 3+86 (21.9)134 (25.0)
Child's birth year
 1988–199354 (13.8)62 (11.6)
 1994–1999127 (32.4)207 (38.7)
 2000–2006211 (53.8)266 (49.7)
Higher level of education of either parent
 Nontertiary223 (56.9)253 (47.3)
 Tertiary169 (43.1)282 (52.7)
Ethnicitya
 European282 (71.9)427 (79.8)
 At least 50% European79 (20.2)79 (14.8)
 At least 50% non-European and not known if 50% European14 (3.6)11 (2.1)
 Indeterminate17 (4.3)18 (3.4)
Household income
 <$20,00028 (7.2)21 (3.9)
 $20,001–40,00067 (17.2)73 (13.9)
 $40,001–70,000115 (29.6)185 (34.6)
 $70,001–100,00093 (23.9)137 (25.7)
 >$100,000 pa86 (22.1)117 (22.9)
Mother's age at child's birth
 <25 years59 (15.1)44 (8.2)
 25–34 years266 (67.9)360 (67.3)
 35+ years67 (17.1)131 (24.5)
Child had a birth defect
 Yes22 (5.7)17 (3.2)
Folic acidb
 None261 (67.4)326 (61.6)
 >0–300 μg44 (11.4)50 (9.5)
 300.1–450 μg37 (9.6)61 (11.5)
 450+ μg45 (11.6)92 (17.4)

Abbreviations: ACT, Australian Capital Territory; NSW, New South Wales; NT, Northern Territory; SA, South Australia; WA, Western Australia.

  • aEuropean = at least 3 European grandparents; 50% European = 2 European grandparents; at least 50% non-European = 2 non-European grandparents and ethnicity of other 2 grandparents unknown; indeterminate = no 2 grandparents with the same ethnicity (i.e., European or non-European) and 2+ grandparents of unknown ethnicity.

  • bMaternal folic acid supplementation in the 3 months prior to the pregnancy.