Table 1 Characteristics of the study subjects and indium exposure profile

	Exposed workers (n = 93)			Non-exposed workers (n = 93)			p Value
	Mean	SD	Range	Mean	SD	Range	p Value
Age (years)	36.8	12.2	20–67	43.6	11.1	22–70	0.0001
Weight (kg)	64.9	9.5	48–93	67.3	9.9	44–95	0.1101
Height (cm)	169.9	5.6	155–183	169.2	6	156–185	0.4509
Current smokers (%)	67.7			52.7			0.0355
Indium in serum (In-S, ng/ml)*	8.25	4.55	ND–116.9	0.25	2.64	ND–1.3	<0.0001
Duration of indium exposure (months)	84.9	54†	13–488

ND, below detection limit.
*Geometric mean and geometric standard deviation.
†Median.
For test of difference in mean, Student or Welch t test (In-S) was adopted. For test of smoking prevalence, χ² test was applied.