Table 3.

Relationship of urinary renal injury indicators with urinary melamine levels or worksites in multivariate regression models

	N	Mean±SD	Median, IQR	Crude		Adjustedb		Adjustedc
				β (±SEM)	P value	β (±SEM)	P value	β (±SEM)	P value
Log10 NAGa
Model 1
Urinary melamine (μg/mmol Cr)	81	0.7±1.5	0.5, 0.3–0.8	0.004 (0.001)	<0.001	0.004 (0.001)	0.001	0.004 (0.001)	0.001
Model 2a
Nonexposed workers	105	0.4±0.2	0.4, 0.3–0.5	1	—	1	—	1	—
Administrators	9	0.6±0.3	0.6, 0.4–0.8	0.140 (0.094)	0.138	0.097 (0.106)	0.365	0.148 (0.106)	0.165
Grinders and packers	16	0.7±0.6	0.7, 0.3–0.9	0.181 (0.072)	0.014	0.065 (0.097)	0.507	0.090 (0.096)	0.350
Manufacturers	14	1.8±3.5	0.9, 0.4–1.4	0.344 (0.077)	<0.001b	0.217 (0.107)	0.044	0.213 (0.105)	0.044c
	N	Normal N (%)	Abnormal N (%)	Crude OR (95% CI)		Adjusted OR (95% CI)d		Adjusted OR (95% CI)e
β2-microglobulinf
Model 1
Urinary melamine (μg/mmol Cr)	81	75 (92.6)	6 (7.4)	1.03 (1.01–1.04)		1.03 (1.01–1.06)		1.03 (1.01–1.06)
Model 2a
Nonexposed workers	105	101 (96.2)	4 (3.8)	1		1		1
Administrators	9	9 (100.0)	0	—		—		—
Grinders and packers	16	15 (93.8)	1 (6.2)	1.68 (0.18–16.01)		0.76 (0.04–13.67)		0.76 (0.04–15.16)
Manufacturers	14	10 (71.4)	4 (28.6)	10.10 (2.19–46.67)		30.18 (1.59–573.90)g		27.94 (1.28–611.62)h

OR, odds ratio; 95% CI, 95% confidence interval.

^aMissing data, n=1 for office staff, n=2 for grinders and packers, and n=2 for manufacturers.

^bP value for trend: P<0.001.

^cP value for trend: P=0.047.

^dAdjusting for age, sex, BMI, educational level, and cigarette smoking.

^eAdjusting for age, sex, BMI, educational level, cigarette smoking, and serum uric acid.

^fMultiple linear regression or logistic regression.

^gP value for trend: P=0.021.

^hP=0.047.