TABLE 2.

Crude and Multivariate Adjusted HRs for Phototherapy and Covariates

Variable	Crude HR (95% CI)	P	Adjusted HR (95% CI)	P
Any phototherapy
No	Reference		Reference	—
Yes	0.95 (0.68 to 1.32)	.75	1.06 (0.78 to 1.45)	.69
Year of birth
1995–2000			Reference	—
2001–2006	1.05 (0.88 to 1.24)	.60	1.09 (0.95 to 1.26)	.23
2007–2011	1.02 (0.77 to 1.36)	.89	1.08 (0.72 to 1.63)	.71
Maternal age
<20 y	0.67 (0.46 to 0.95)	.03	0.68 (0.49 to 0.95)	.02
20 to <25 y	0.83 (0.66 to 1.03)	.09	0.84 (0.71 to 1)	.05
25 to <30 y	0.87 (0.73 to 1.05)	.16	0.89 (0.74 to 1.07)	.22
30 to <35 y	Reference		Reference	—
35 to <40 y	0.85 (0.68 to 1.06)	.15	0.83 (0.65 to 1.07)	.15
≥40 y	1.01 (0.7 to 1.45)	.96	0.97 (0.66 to 1.42)	.88
Race or ethnicity
White	Reference		Reference	—
Asian	0.35 (0.27 to 0.46)	<.0005	0.35 (0.29 to 0.42)	<.0005
Black	0.77 (0.59 to 0.99)	.04	0.79 (0.53 to 1.18)	.25
Hispanic	0.54 (0.45 to 0.66)	<.0005	0.56 (0.44 to 0.7)	<.0005
Other	0.63 (0.45 to 0.88)	.007	0.64 (0.47 to 0.87)	.01
Gestational age
<38 wk			Reference	—
≥38 wk	1.07 (0.85 to 1.33)	.57	1.17 (1.01 to 1.35)	.04
Birth wt
<2500 g	0.92 (0.6 to 1.41)	.72	0.89 (0.57 to 1.41)	.63
2500 to <4200 g	Reference		Reference	—
≥4200 g	1.4 (1.09 to 1.78)	.007	1.29 (1.04 to 1.61)	.02
Direct antiglobulin test
Not done	0.93 (0.79 to 1.09)	.37	0.94 (0.82 to 1.07)	.35
Negative			Reference	—
Positive	1.05 (0.63 to 1.74)	.85	1.13 (0.69 to 1.86)	.63
Maximum total serum bilirubin, mg/dL
Not done or <10			Reference	—
10–14.9	0.9 (0.72 to 1.13)	.36	0.92 (0.8 to 1.05)	.20
15–19.9	0.72 (0.55 to 0.94)	.02	0.74 (0.53 to 1.02)	.07
≥20	1.03 (0.63 to 1.66)	.92	1.05 (0.7 to 1.59)	.81

—, no point estimates, 95% CI, or P value for the reference categories of each risk factor.