Table 3. The odds ratios of high blood pressure at the age of 7 years in preterm infants with different concentrations and subtypes of serum bilirubin at 48h after birth.

Bilirubin		High blood pressure at the age of 7 years
		n/N (%)	Model 1		Model 2		Model 3
			OR	95% CI	OR	95% CI	OR	95% CI
Unconjugated bilirubin a	< 3mg/dl	29/317 (9.2)	1	-	1	-	1	-
	≥ 3mg/dl, < 6mg/dl	43/326 (13.2)	1.51	0.92, 2.49	1.54	0.93, 2.55	1.55	0.93, 2.57
	≥ 6mg/dl, <9mg/dl	89/659 (13.5)	1.61	1.04, 2.50	1.55	0.99, 2.43	1.55	1.00, 2.46
	≥ 9mg/dl, < 12mg/dl	75/539 (13.9)	1.63	1.04, 2.56	1.51	0.95, 2.41	1.51	0.95, 2.42
	≥ 12mg/dl	109/728 (15.0)	1.79	1.16, 2.75	1.54	0.97, 2.44	1.54	0.96, 2.46
Conjugated bilirubinb	< 1mg/dl	272/2074 (13.1)	1	-	1	-	1	-
	≥ 1mg/dl, < 2mg/dl	58/378 (15.4)	1.20	0.88, 1.63	1.11	0.80, 1.53	1.08	0.73, 1.53
	≥ 2mg/dl	15/117 (12.8)	0.95	0.55, 1.66	0.85	0.48, 1.50	0.88	0.47, 1.58

Model 1: crude odds ratios; Model 2: Adjusted for race (white, black, and other races), sex (male and female), gestational age (as a categorical variable), birth weight (<2500g, and ≥2500g), transfusion (yes and no), hypertensive disorders during pregnancy (none, moderate, and severe), maternal smoking (0, 1–19 and 20 cigarette per day during pregnancy) and socioeconomic status (comprised of 5 categories as assessed by the original CPP investigators); Model 3: adjusted for the same factors as model 2 in Generalized Estimating Equation model

^a Adjusted by direct serum bilirubin additionally;

^b Adjusted by indirect serum bilirubin additionally;