Table 1.

Distribution of birth characteristics of the child, mother, and residence by case/control status.

	Cases (n=307)		Controls (n=1,013)		p-value^a

	N	%	N	%
Female (v. Male)	130	42.4	518	51.1	0.02
Race/Ethnicity^b					0.001
Non-Hispanic (NH) White	207	67.4	702	69.3
NH African American	20	6.5	122	12.0
NH American Indian	29	9.5	88	8.7
NH Other	14	4.6	22	2.2
Hispanic	37	12.1	79	7.8
Maternal Age at Child's Delivery					0.34
<20 years	40	13.0	162	16.0
20-34 years	240	78.2	778	76.8
≥35 years	27	8.8	73	7.2
Parity					0.05
0 previous deliveries	112	36.5	430	42.5
1 previous delivery	91	29.6	320	31.6
2 previous deliveries	67	21.8	159	15.7
3+ previous deliveries	37	12.1	104	10.3
Tobacco Use During Pregnancy (1991-2010)					0.87
Yes	36	13.8	126	14.4
No	198	75.9	689	78.7
Unknown	27	10.3	60	6.9
Maternal Education					0.33
>High School Education	118	38.4	406	40.1
Completed High School	103	33.6	361	35.6
<High School Education	81	26.4	229	22.6
Unknown	5	1.6	17	1.7
Urban Census Block at Birth Residence (v. Rural)	249	81.1	830	81.9	0.63
Complete Street Address (v. Rural Route)	300	97.7	989	97.6	0.94

p-value based on univariate conditional logistic regression

Unknown Hispanic ethnicity classified as non-Hispanic, NH Other includes Asian, Pacific Islander, other unclassified ethnicity, and unknown ethnicity.