Table 2.

Odds ratios (95% confidence interval) of occurrence of Down syndrome California, 1996–97

	Crude	95% CI		Fully adjusted*	95% CI
		Lower	Upper		Lower	Upper
Sex of infants
Boy	1			1
Girl	0.85	0.72	1.00	0.84	0.71	0.99
Education of mother
Primary	1.99	1.52	2.62	2.80	2.12	3.72
Vocational	0.97	0.72	1.31	2.24	1.62	3.10
Secondary	1.16	0.90	1.50	1.87	1.44	2.44
University	1			1
P for trend	<0.001			<0.001
Maternal age
-19	1			1
20–22	1.32	0.84	2.08	1.66	0.95	2.92
23–25	1.45	0.94	2.26	2.05	1.14	3.68
26–28	1.40	0.90	2.17	2.18	1.20	3.99
29–31	1.71	1.12	2.63	2.74	1.49	5.04
32–34	3.29	2.20	4.92	5.47	3.00	9.98
35–37	3.72	2.45	5.66	6.27	3.37	11.64
38–40	8.21	5.43	12.40	12.34	6.61	23.05
41–43	20.07	13.12	30.71	28.42	14.98	53.91
44+	19.40	10.30	36.55	27.57	12.22	62.21
Paternal age
-19	1			1
20–22	1.11	0.59	2.10	0.85	0.44	1.67
23–25	1.13	0.61	2.06	0.69	0.35	1.37
26–28	1.27	0.71	2.29	0.65	0.32	1.31
29–31	1.92	1.09	3.38	0.83	0.41	1.66
32–34	1.94	1.10	3.43	0.67	0.33	1.37
35–37	2.55	1.44	4.51	0.68	0.33	1.40
38–40	2.47	1.36	4.49	0.54	0.26	1.13
41–43	6.33	3.55	11.27	1.02	0.49	2.11
44+	6.37	3.58	11.34	0.86	0.41	1.79

Note: * -Adjusted for all variables in the Table.