Table 8.

Raw numbers of occurrence of covariates in cases and controls. Occurrence covariate/number that answered the question

Covariate	Cases				Controls
Year	1987–1990	1991–1995	1996–2000	2001–2005	2002–2003
Total	19	27	59	37	2,841
Primary prone	4/8	11/15	12/53	9/36	83/2,825
Secondary prone	0/8	0/15	15/53	9/36	27/2,825
Premature	3/8	1/9	10/50	13/36	317/2,809
Male gender	12/19	16/27	36/59	17/37	1,434/2,837
Both parents low educated	–	–	23/44	18/27	1,022/2,646
One parent low educated	–	–	8/44	5/27	827/2,646
One parent non-European Caucasian	0/3	0/2	5/50	3/35	341/2,570
Both parents non-European Caucasian	1/3	1/2	5/50	2/35	99/2,570
Started breastfeeding	2/2	–	29/47	19/34	2,264/2,823
Prenatal maternal smoking	1/1	–	16/46	10/30	376/2,814
Postnatal smoking one parent	–	0/1	16/48	14/35	653/2,808
Postnatal smoking both parents	–	1/1	13/48	12/35	260/2,808
Postnatal maternal smoking	–	1/1	19/48	16/34	396/2,827
Postnatal paternal smoking	–	1/1	23/46	21/33	792/2,818