Table 7. Linear and multiple linear regression analysis between exposure, inhalable cobalt adjusted for the use of respirators and cobalt on skin, and uptake of cobalt in blood and urine.

Analysis	Uptake	Exposure	n	r2	β	95% CI	p-value
Simple linear	Blood cobalt	Inhalable cobalt	69	0.16	199	89–310	0.0010
regression		Skin cobalt	69	0.12	0.010	0.0030–0.016	0.0030
	Urine cobalt	Inhalable cobalt	70	0.15	5759	2392–9126	0.0010
		Skin cobalt	70	0.0030	0.040	-0.16–0.25	0.65
Multiple linear	Blood cobalt	Inhalable cobalt	69	0.29	203	101–306	<0.0010
regression		Skin cobalt			0.010	0.0040–0.020	0.0040
	Urine cobalt	Inhalable cobalt	70	0.15	5779	2392–9165	0.0010
		Skin cobalt			0.10	-0.14–0.24	0.60

n: number of samples; r²: explained variance; β: regression coefficient; CI: confidence interval