Table 3.

Mixed-effect model of the association of covariates with serum TNF-α level.

Parameter	Estimate	SE	p
Age (year)	0.24	0.05	<0.0001 *
Gender (male vs. female)	3.76	1.11	0.0008 *
BMI (kg/m2)	−0.51	0.13	<0.0001 *
Smoking (yes vs. no)	−0.99	0.96	0.3061
Drinking alcohol (yes vs. no)	3.23	3.17	0.3096
WBC (103/µL)	1.25	0.26	<0.0001 *
Pb (μg/L)	0.23	0.0093	<0.0001 *
Cd (μg/L)	7.65	1.01	<0.0001 *
As (μg/L)	1.23	0.15	<0.0001 *
Se (μg/L)	0.03	0.0051	<0.0001 *
Co (μg/L)	17.22	2.43	<0.0001 *
Cu (μg/L)	0.01	0.0014	<0.0001 *
Zn (μg/L)	0.001	0.0002	<0.0001 *

SE—Standard error; WBC—white blood cell; * Bonferroni’s correction p < 0.01.