Table 2.

Summary of (A) cumulative and (B–C) effective linear mixed effects models with creatinine as an independent variable and with estimated HDA half-life (T_1/2) of 70 or 174 min for predicting natural log-transformed urine HDA levels in automotive spray painters exposed to HDI

Exposure model		Exposure variable	Estimate	Standard error	P value	AIC	R2
A. Cumulative	1	lnBZC	0.157	0.069	0.022	1037	0.23
		lncreatinine	1.254	0.168	<0.0001
	2	lnBZC-APF	0.179	0.055	0.001	1032	0.26
		lncreatinine	1.290	0.167	<0.0001
	3	lndermal	0.151	0.058	0.010	1036	0.25
		lncreatinine	1.256	0.168	<0.0001
	4	lnBZC	0.076	0.086	0.381	1038	0.25
		lndermal	0.113	0.074	0.124
		lncreatinine	1.253	0.168	<0.0001
	5	lnBZC-APF	0.139	0.065	0.032	1035	0.28
		lndermal	0.079	0.068	0.244
		lncreatinine	1.281	0.167	<0.0001
		Worker var	0.930
		Residual var	1.762
B. Effective T1/2 = 70 min	1	lnBZC	0.120	0.063	0.056	1039	0.22
		lncreatinine	1.270	0.168	<0.0001
	2	lnBZC-APF	0.148	0.051	0.004	1034	0.25
		lncreatinine	1.303	0.168	<0.0001
	3	lndermal	0.134	0.053	0.012	1037	0.24
		lncreatinine	1.275	0.168	<0.0001
	4	lnBZC	0.040	0.082	0.625	1039	0.24
		lndermal	0.112	0.070	0.108
		lncreatinine	1.275	0.168	<0.0001
	5	lnBZC-APF	0.109	0.062	0.081	1037	0.27
		lndermal	0.072	0.064	0.266
		lncreatinine	1.298	0.168	<0.0001
		Worker var	0.959
		Residual var	1.769
C. Effective T1/2 = 174 min	1	lnBZC	0.150	0.069	0.031	1038	0.23
		lncreatinine	1.263	0.168	<0.0001
	2	lnBZC-APF	0.173	0.055	0.002	1033	0.26
		lncreatinine	1.300	0.168	<0.0001
	3	lndermal	0.151	0.058	0.009	1036	0.25
		lncreatinine	1.267	0.168	<0.0001
	4	lnBZC	0.068	0.086	0.431	1038	0.25
		lndermal	0.118	0.072	0.103
		lncreatinine	1.265	0.168	<0.0001
	5	lnBZC-APF	0.132	0.064	0.039	1035	0.28
		lndermal	0.083	0.067	0.214
		lncreatinine	1.293	0.167	<0.0001
		Worker var	0.930
		Residual var	1.765

lnBZC = natural log-transformed BZC; lnBZC-APF = natural log-transformed respirator-adjusted BZC; lndermal = natural log-transformed dermal exposure level; lncreatinine = natural log-transformed creatinine concentration; var = variance.