Table 4

Factors influencing urinary excretion of β₂-microglobulin in nickel-cadmium battery workers

	Categories of pack-years		Never/ever smoking
	Independent variables	Coefficient (95% CI)	Independent variables	Coefficient (95% CI)
Model 1
Log β2-mU (μg/g CrU)	Log CdU (μg/g CrU)	0.120 (0.022 to 0.218)	Log CdU (μg/g CrU)	0.120 (0.022 to 0.219)
			Gender	−0.101 (−0.217 to 0.014)
Model 1 with β2-mU>20 μg/g CrU
Log β2-mU (μg/g CrU)	Log CdU (μg/g CrU)	0.166 (0.090 to 0.243)	Log CdU (μg/g CrU)	0.177 (0.100 to 0.253)
	Category of pack-years (high)	0.166 (0.025 to 0.308)
Model 2
Log β2-mU (μg/g CrU)	Log CdU (μg/g CrU) CrU adjusted	0.083 (−0.006 to 0.173)	Log CdU (μg/g CrU) CrU adjusted	0.078 (−0.005 to 0.174)
	Log CrU (g/l)	−0.937 (−1.113 to −0.760)	Log CrU (g/l)	−0.907 (−1.02 to −0.429)
Model 2 with β2-mU>20 μg/g CrU
Log β2-mU (μg/g CrU)	Log CdU (μg/g CrU) CrU adjusted	0.150 (0.078 to 0.222)	Log CdU (μg/g CrU) CrU adjusted	0.153 (0.091 to 0.215)
	Log CrU (g/l)	−0.638 (−0.777 to −0.498)	Log CrU (g/l)	−0.614 (−0.706 to −0.249)
	Category of pack-years (high)	0.144 (0.017 to 0.271)
Model 3
Log β2-mU (μg/l)	Log CdU (μg/l)	0.083 (−0.001 to 0.177)	Log CdU (μg/g CrU)	0.088 (−0.001 to 0.177)
Model 3 with β2-mU>20 μg/g CrU
Log β2-mU (μg/l)	Log CdU (μg/l)	0.150 (0.078 to 0.222)	Log CdU (μg/l)	0.153 (0.091 to 0.215)
	Log CrU (g/l)	0.286 (0.135 to 0.436)	Log CrU (g/l)	0.308 (0.179 to 0.437)
	Category of pack-years (high)	0.144 (0.017 to 0.271)

The models are the same as described in table 3.
For each model, age and gender were forced in the regression.
Model 1, N=468; model 1 with β₂-mU>20 μg/g CrU, N=393; models 2 and 3, N=492; models 2 and 3 with β₂-mU>20 μg/g CrU, N=416.
β₂-mU, concentration of β₂-microglobulin in urine; CdU, concentration of cadmium in urine; CrU, concentration of creatinine in urine.