Table 3.

Risk Ratios for Preterm Birth in Relation to Umbilical Cord Serum Log Cytokine Levels, Infant Growth Project, Jefferson County, Alabama, 1985–1988

	Model 1a (n = 370)		Model 2b (n = 370)		Model 3c (n = 319)
	RR	95% CI	RR	95% CI	RR	95% CI
Interferon γ	1.26*	1.02, 1.55	1.24*	1.01, 1.52	1.16	0.93, 1.45
Tumor necrosis factor α	2.00*	1.53, 2.62	2.18*	1.53, 3.10	2.00*	1.31, 3.06
Interleukin-12p70	1.32	0.90, 1.92	1.25	0.86, 1.82	1.16	0.77, 1.76
Interleukin-4	1.09	0.89, 1.33	1.06	0.87, 1.29	1.10	0.89, 1.36
Interleukin-10	1.27*	1.02, 1.57	1.26*	1.01, 1.57	1.18	0.96, 1.46

Abbreviations: CI, confidence interval; RR, risk ratio.

^*P < 0.05.

^aResults were unadjusted.

^bResults were adjusted for maternal age, race/ethnicity, weight, and smoking.

^cResults were adjusted for smoking, use of antibiotics, and intrapartum fever.