Table 4: Multivariate linear regression models to evaluate associations between biochemical markers of renal function with some demographic variables,

with kidney biomarkers and with BLL.

	β	P	95% CI
BUN*
Creatinine levels	13.13	0.000	8.61 - 17.65
Abnormal creatinine levels**
Gender	-0.171	0.000	-0.236 - 0.105
BMI	-0.005	0.002	-0.008 - 0.001
BUN	0.003	0.025	0.0004 - 0.007
Uric acid levels	0.051	0.000	0.031 - 0.071
Abnormal uric acid***
Years of work	0.003	0.017	0.0006 - 0.006
eGFR^&
Creatinine	1.33	0.000	1.08 - 1.58
Uric acid	-0.044	0.001	-0.070 - 0.018

*Adjusted for uric acid levels, creatinine levels, anemia, and history of kidney disease.

**Adjusted for gender, age, BMI, BUN, uric acid levels.

***Adjusted for gender, age, BMI, years of work, creatinine, highest BBL, baseline BLL and category II.

^&Adjusted for age, gender, baseline and highest BLL, proteinuria.