Table 3.

Unadjusted association of risk of neural tube defects with individual-level indicators of socio-economic status

	Neural tube defects (n = 283)		Anencephaly (n = 123)		Spina bifida (n = 160)		Controls (n = 552)
	Cases	OR [95% CI]	Cases	OR [95% CI]	Cases	OR [95% CI]	No.
Maternal education
<High school	112	1.7 [1.2, 2.6]	49	1.6 [1.0, 2.7]	63	1.8 [1.1, 3.0]	157
High school	56	1.0 Reference	26	1.0 Reference	30	1.0 Reference	135
Some college	62	1.3 [0.8, 2.0]	26	1.2 [0.6, 2.1]	36	1.4 [0.8, 2.4]	117
≥Bachelor’s degree	51	0.9 [0.6, 1.4]	22	0.8 [0.4, 1.5]	29	0.9 [0.5, 1.7]	137
Household income
<$10 000	54	0.7 [0.4, 1.2]	19	0.6 [0.3, 1.1]	35	0.8 [0.4, 1.5]	122
$10 000–$19 999	52	1.0 [0.6, 1.6]	22	0.9 [0.4, 1.8]	30	1.0 [0.5, 1.9]	86
$20 000–$29 999	38	1.0 Reference	17	1.0 Reference	21	1.0 Reference	60
$30 000–$39 999	17	0.7 [0.4, 1.4]	7	0.7 [0.3, 1.7]	10	0.8 [0.3, 1.8]	38
$40 000–$49 999	20	1.5 [0.7, 3.1]	7	1.2 [0.4, 3.2]	13	1.8 [0.8, 4.1]	21
$50 000+	68	0.6 [0.4, 1.1]	33	0.7 [0.4, 1.4]	35	0.6 [0.3, 1.1]	166
Maternal employment
Yes	166	0.9 [0.7, 1.2]	76	1.0 [0.7, 1.5]	90	0.8 [0.6, 1.2]	338
Paternal employment
Yes	269	0.9 [0.5, 1.4]	116	1.5 [0.7, 3.4]	153	0.6 [0.4, 1.1]	530

OR, odds ratio; CI, confidence interval.