Abstracts: ISEE 21st Annual Conference, Dublin, Ireland, August 25-29, 2009: Symposium Abstracts
*School of Medicine, Keio University, Tokyo, Japan; and †Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
Background and Object:
Except for specificity of association, authors have demonstrated a causal relationship between indium dust exposure and lung interstitial damage. The aim of this study was to assess the specificity of the damage by contrasting the differences in lung interstitial damage between indium-exposed workers who started working before (Group B) and after (Group A) improvements (reduction of indium concentration) in the working environment.
Baseline health checkups were performed on 500 indium-exposed workers in 13 factories. Detailed job history was obtained from 379 workers in Group B and 109 in Group A. Average exposure duration, mean age, and smoking rate in Groups B and A were 67.1 and 17.3 months, 37.6 and 33.0 years, and 71.2 and 66.1%. Indium in serum (In-S) was measured as an exposure index. KL-6, SP-D and SP-A were assessed as early effect markers of lung interstitial damage.
Geometric means of In-S in Groups B and A were 3.24 and 0.15 ng/ml. Age- and smoking-adjusted odds ratios of Group A vs. Group B exceeding reference values of KL-6, SP-D and SP-A were 0.09 (95%CI 0.03–0.26), 0.22 (0.09–0.54) and 0.48 (0.26–0.91). Geometric means of KL-6, SP-D and SP-A were 380 U/ml, 61.7 ng/ml and 37.7 ng/ml in Group B, and 216, 41.7 and 28.6 in Group A; all Group A values were significantly lower.
Reduction of indium exposure seemed to reduce the early effects of indium on the lung interstitium. This suggests the specificity of the association between indium exposure and lung interstitial damage.