Table 1.

Maternal and offspring characteristics of childhood cancer cases and controls, 1996–2014.

	N cases = 2,029	Proportion (%) of cases	N controls = 10,103	Proportion (%) of controls
Maternal characteristics
Maternal age (years)
<25	355	17.5	1,872	18.5
25–29	639	31.5	3,246	32.1
≥30	1,035	51.0	4,985	49.3
Parity
Primiparous	847	41.7	4,098	40.6
Multiparous	1,182	58.3	6,005	59.4
Maternal smoking
Yes	291	14.3	1,447	14.3
No	1,680	82.8	8,404	83.1
Unknown	58	2.9	252	2.5
A diagnosis of autoimmune disease (AI) prior to delivery	19	0.9	134	1.3
Any AI medication purchase 3 months before/during pregnancy (ATC-code)	169	8.3	888	8.8
IBD medication (A07E)	13	0.6	65	0.6
Systemic corticosteroids (H02)	21	1.0	107	1.1
Immunosuppressants (L04)	3	0.1	13	0.1
Anti-inflammatory and -rheumatic products (M01)	141	6.9	761	7.5
IBD	12	0.6	61	0.6
IBD diagnosis, no medication	2	0.1	12	0.1
Rheumatic disease	7	0.3	74	0.7
Rheumatic disease diagnosis, no medication	1	0.05	38	0.4
Offspring characteristics
Offspring sex
Male	1,092	53.8	5,431	53.8
Female	937	46.2	4,672	46.2
Multiple pregnancy
No	1,962	96.7	9,784	96.8
Yes	67	3.3	319	3.2
Gestational age
<37 weeks	141	6.9	537	5.3
≥37 weeks	1,888	93.1	9,566	94.7
Weight for gestational age (size at birth)
Small for gestational age (SGA)	55	2.7	217	2.1
Appropriate for gestational age (AGA)	1,881	92.7	9,587	94.9
Large for gestational age (LGA)	93	4.6	299	3.0
Delivery type
Vaginal birth	1,675	82.6	8,470	83.8
Cesarean section	354	17.4	1,627	16.1
Unknown	0	0.0	6	0.5