Table 5.

Multilevel ordered logistic regression results for preterm birth severity among Black and White mothers (n = 6,413,216 births).

County measures	OR (95% CI)	OR (95% CI)
Black maternal race (White = reference)	1.76 (1.71, 1.82)	1.69 (1.64, 1.74)
Same-race physicians (per 1000 residents)		0.97 (0.96, 0.98)
Same-race residents in primary care shortage area (10%)		1.02 (1.01, 1.02)
Same-race uninsurance rate, adults aged 18–44 (10%)		1.02 (1.01, 1.04)
Sufficiency of publicly-funded contraceptives (10%)		0.99 (0.98, 1.00)
Public health expenditures ($100 per resident)		0.99 (0.98, 1.00)
Variance components	Variance (SE)	Variance (SE)
Random county effect	0.0172 (0.0015)	0.0149 (0.0015)
Random race effect	0.0149 (0.0024)	0.0120 (0.0023)

Note. Bold font indicates statistical significance at p < .05. Estimates adjusted for maternal age, parity, infant sex, and the following county variables: urban-rural classifications, Black population share, Black-White spatial exposure/isolation index, poverty rate among Black persons aged 15 to 44, median household income for total population, and hospital beds. Per capita primary care physicians is omitted due to conceptual overlap with same-race physicians for births to White mothers given the majority share of White physicians.