Table 2.

Parameter estimates for very preterm birth among black women

	Crude^a			M1 -- Age, parity and prior preterm birth			M2 -- Socioeconomic condition pathway			M3 -- Maternal health pathway			M4 -- All covariate model			M5 -- Dual Index model
	OR	95% CI		OR	95% CI		OR	95% CI		OR	95% CI		OR	95% CI		OR	95% CI

Individual level
Maternal age
<15	2.12	1.93	2.34	2.23	2.03	2.45	1.66	1.51	1.83	2.29	2.08	2.50	1.80	1.62	1.97	1.80	1.64	1.99
15–19	1.18	1.15	1.21	1.22	1.18	1.25	0.97	0.94	1.00	1.23	1.19	1.27	1.02	0.98	1.05	1.02	0.98	1.05
20–24	0.96	0.93	0.98	0.96	0.94	0.99	0.86	0.84	0.89	0.97	0.94	0.99	0.88	0.85	0.90	0.88	0.86	0.90
25–29	ref			ref			ref			ref			ref			ref
30–34	1.21	1.17	1.24	1.21	1.17	1.24	1.30	1.26	1.34	1.19	1.16	1.23	1.26	1.23	1.30	1.27	1.23	1.31
35–39	1.42	1.37	1.47	1.41	1.37	1.46	1.54	1.49	1.60	1.35	1.31	1.40	1.46	1.41	1.51	1.46	1.41	1.51
40+	1.71	1.62	1.82	1.71	1.61	1.81	1.85	1.74	1.96	1.58	1.49	1.68	1.70	1.60	1.80	1.70	1.61	1.80
Parity
Primiparous	ref			ref			ref			ref			ref			ref
Multiparous	1.07	1.05	1.09	1.00	0.97	1.02	0.97	0.95	0.99	0.97	0.95	1.00	0.96	0.94	0.98	0.96	0.94	0.98
Prior preterm or SGA birth
Yes	4.75	4.54	4.98	4.77	4.57	5.00	4.69	4.47	4.91	4.56	4.34	4.79	4.53	4.31	4.74	4.54	4.34	4.75
No	ref			ref			ref			ref			ref			ref
Maternal education
<12 years	1.27	1.25	1.30				1.21	1.18	1.24				1.15	1.11	1.18	1.15	1.12	1.18
12 years	1.10	1.08	1.12				1.08	1.06	1.11				1.06	1.04	1.09	1.06	1.04	1.09
>12 years	ref						ref						ref			ref
Marital status
Married	ref						ref						ref			ref
Unmarried	1.36	1.33	1.39				1.47	1.44	1.51				1.43	1.40	1.47	1.43	1.40	1.47
Chronic hypertension
Yes vs no	3.03	2.87	3.18							2.77	2.64	2.93	2.75	2.61	2.90	2.75	2.61	2.90
Diabetes
Yes vs. no	0.95	0.90	1.00							0.90	0.85	0.95	0.91	0.87	0.97	0.91	0.87	0.96
Tobacco use^c
Yes vs no	1.58	1.54	1.63							1.53	1.48	1.57	1.38	1.34	1.42	1.38	1.34	1.42
MSA-level
Isolation^b	1.11	1.08	1.14	1.12	1.08	1.15	1.10	1.07	1.14	1.13	1.10	1.17	1.11	1.08	1.15	1.15	1.10	1.19
Clustering^b	1.05	1.02	1.08													0.95	0.92	0.99
Population size
<500,000	1.09	1.04	1.16	1.10	1.04	1.16	1.08	1.02	1.14	1.08	1.03	1.14	1.07	1.01	1.13	1.05	0.99	1.11
500k – 1 million	1.08	1.01	1.15	1.09	1.02	1.16	1.09	1.01	1.16	1.08	1.01	1.15	1.07	1.00	1.14	1.07	1.00	1.14
1 million +	ref			ref			ref			ref			ref			ref
Region
Northeast	ref			ref			ref			ref			ref			ref
Southeast	0.98	0.92	1.05	1.04	0.96	1.12	1.07	0.99	1.15	1.07	1.00	1.15	1.09	1.02	1.17	1.04	0.97	1.13
Midwest	0.98	0.91	1.06	1.01	0.93	1.09	1.00	0.92	1.08	1.01	0.93	1.09	1.00	0.93	1.09	1.01	0.94	1.09
West	0.84	0.76	0.92	0.86	0.78	0.95	0.88	0.80	0.98	0.93	0.84	1.03	0.94	0.85	1.03	0.91	0.83	1.01
σ ² _α					0.134			0.135			0.126			0.129			0.125
DIC					416696			415134			414758			413557			413559

Abbreviations: MSA: metropolitan statistical area

Crude models for individual covariates all include random intercepts for MSA, and adjustment for region and population size

The odds ratios for segregation indices refer to the change in risk of very preterm birth for a 1-SD change in segregation index

California does not collect smoking on birth certificates so smoking parameter estimates exclude births in California. The variable was coded such that California births are not omitted from the model so all other parameters are inclusive.