Open AccessPossibility of lung cancer risk in indium‐exposed workers: An 11‐year multicenter cohort study
Author(s) -
Nakano Makiko,
Omae Kazuyuki,
Tanaka Akiyo,
Hirata Miyuki
Publication year - 2019
Publication title -
journal of occupational health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.664
H-Index - 59
ISSN - 1348-9585
DOI - 10.1002/1348-9585.12050
Subject(s) - medicine , lung cancer , cohort , incidence (geometry) , medical surveillance , indium , lung , nuclear medicine , gastroenterology , pathology , physics , materials science , optics , metallurgy
Background We established a causal relationship between indium exposure and lung interstitial and emphysematous effects. Lung cancer has been clearly demonstrated in rats and mice exposed to indium phosphide and in rats exposed to indium tin oxide. However, no information is available on human indium‐related lung cancer. Methods The baseline studies were conducted on 381 indium‐exposed and 150 referent workers in 11 factories from 2003 to 2006. Items examined included indium concentration in serum (In‐S), occupational history, Krebs von den Lungen‐6 (KL‐6), chest high‐resolution computed tomography (HRCT), medical history, smoking habits, and subjective symptoms. Subjects received follow‐up health checkups, and a total of 220 indium‐exposed and 26 nonexposed workers were examined at least once with chest HRCT from 2013 to 2018. Results Four lung cancer cases were identified only in indium‐exposed workers. Two were prevalent cases and two were incident cases. The averages (range) of age (years), exposure duration (years), In‐S (μg/L), and KL‐6 (U/mL) at the baseline survey were 58 (50‐74), 1.7 (0.3‐4.8), 3.1 (0.3‐9.7), and 663 (414‐942). The mean (range) latency from initial indium exposure was 5.3 (0.4‐11) years. The HRCT findings in two incident cases were mild interstitial/emphysematous change and mild interstitial change. The standardized incidence ratio (SIR) of the incident cases was 1.89 (95%CI 0.52‐6.88). Conclusions Although the SIR was not statistically significant, there was an undeniable possibility of indium‐related lung cancer due to the short follow‐up duration being insufficient to disclose lung cancer and the small number of lung cancer cases. Further follow‐up is necessary.