Table 3 Dose-effect and dose-response relations between In-S and KL-6, SP-D, SP-A, interstitial change on lung HRCT, and emphysematous change on lung HRCT

Group	In-S		n	KL-6		SP-D		SP-A		Prevalence†
Group	Range	Mean	n	GM	GSD	GM	GSD	GM	GSD	KL-6	SP-D	SP-A	HRCT-I	HRCT-E
0	<1.0	0.5	8	257.3	1.4	57.5	2.2	32.9	1.3	0.0	25.0	25.0	0.0	0.0
1	1.0–4.9	2.5	24	266.3	1.7	56.9	1.8	33.0	1.6	8.3	12.5	25.0	0.0	0.0
2	5.0–9.9	7.5	13	432.1	1.5	74.4	1.6	39.4	1.3	38.5	15.4	46.2	0.0	7.7
3	10.0–19.9	13.5	18	444.9	1.4	86.7	1.9	36.2	1.6	33.3	44.4	38.9	5.6	5.6
4	20.0–29.9	24.2	11	847.9**	2.5	127.5	2.2	38.9	1.6	81.8	54.6	36.4	9.1	9.1
5	30.0–49.9	41.2	10	867.1**	1.9	116.3*	1.8	57.9*	1.3	80.0	80.0	80.0	30.0	10.0
6	⩾50.0	80.4	9	1951.0**	1.8	179.0**	1.5	61.7**	1.4	100.0	88.9	77.8	11.1	33.3
p for trend				<0.001		<0.001		<0.001		<0.001	<0.001	<0.001	0.0166	0.0095

GM, geometric mean; GSD, geometric standard deviation.
HRCT-I, HRCT-E: interstitial and emphysematous change on lung HRCT.
†Prevalence (%) of workers exceeding the reference values and of those with interstitial or emphysematous change on lung HRCT.
*p<0.05; **p<0.01 by Dunnett multiple comparison test compared to Group 0. Age- and smoking-adjusted trend was tested applying a multiple regression model for KL-6, SP-D and SP-A, and a logistic regression model for prevalence data.