Interstitial lung disorders in the indium workers of Korea: An update study for the relationship with biological exposure indices

Background: Korea is one of the highest indium-consuming countries worldwide. The present study aims to determine the relationship between interstitial lung disorders and indium exposure in Korea. Methods: In 50 indium workers from seven plants, the effect of serum indium on the lungs was determined using laboratory tests, spirometry, and high-resolution computed tomography (HRCT). Results: Higher serum indium and Krebs von den Lungen-6 (KL-6) levels were associated with HRCT-detected interstitial lung changes. Workers with high serum indium levels (≥3μg/L) had longer exposure durations and a higher prevalence of HRCT-detected interstitial lung changes. KL-6 and surfactant protein-D (SP-D) levels were significantly higher in the highest serum indium quartile than the lowest quartile. Significant dose-effect relationships existed between serum indium levels and KL-6, SP-D levels and the prevalence of HRCT-detected interstitial lung changes. Conclusions: Workforce medical surveillance should be established to prevent indium-induced interstitial lung disease in Korea.