Table2. Results of the multivariate regression analysis for special educational needs.

Variable	OR	(99% CI)	p
Birth weight
<750g	12.83	(7.48–22.03)	<0.001
750–999g	7.08	(4.60–10.89)	<0.001
1000–1249g	3.93	(2.48–6.22)	<0.001
1250–1499g	4.63	(3.22–6.64)	<0.001
1500–1749g	3.66	(2.60–5.16)	<0.001
1750–1999g	2.48	(1.85–3.33)	<0.001
2000–2249g	1.76	(1.37–2.25)	<0.001
2250–2499g	1.83	(1.53–2.19)	<0.001
2500–2749g	1.43	(1.24–1.65)	<0.001
2750–2999g	1.32	(1.17–1.47)	<0.001
3000–4500g (reference)	1.00
>4500g	1.10	(0.81–1.50)	0.410
Sex
Female (reference)	1.00
Male	1.88	(1.75–2.03)	<0.001
Social status group
Lower	5.96	(5.21–6.82)	<0.001
Middle	2.36	(2.09–2.66)	<0.001
Upper (reference)	1.00
Immigration background and German skills
German (reference)	1.00
Immigrant family: – child and parent have good German skills	0.39	(0.34–0.45)	<0.001
– child or parent has poor German skills	0.96	(0.84–1.10)	0.475
– child and parent have poor ‧German skills	1.63	(1.43–1.86)	<0.001
Single parent
Yes	1.21	(1.12–1.31)	<0.001
No (reference)	1.00
Nursery school/kindergarten
≤ 2 years (reference)	1.00
>2 years	0.82	(0.73–0.91)	<0.001

OR. Odds Ratio; 99% CI. 99% confidence interval