Department of Preventive Medicine and Public Health, Keio University School of Medicine, Tokyo, Japan.
Environmental Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
J Occup Health. 2019 May;61(3):251-256. doi: 10.1002/1348-9585.12050. Epub 2019 Mar 20.
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.
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.
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).
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.
我们确立了铟暴露与肺间质和肺气肿效应之间的因果关系。在暴露于磷化铟和氧化铟锡的大鼠和小鼠中已经明确证实了肺癌，而在人类中，尚无与铟相关的肺癌的信息。
从 2003 年至 2006 年，在 11 家工厂中对 381 名铟暴露工人和 150 名对照工人进行了基线研究。检查的项目包括血清中的铟浓度（In-S）、职业史、Krebs von den Lungen-6（KL-6）、胸部高分辨率计算机断层扫描（HRCT）、病史、吸烟习惯和主观症状。对研究对象进行了随访健康检查，共有 220 名铟暴露工人和 26 名非暴露工人在 2013 年至 2018 年期间至少接受了一次胸部 HRCT 检查。
仅在铟暴露工人中发现了 4 例肺癌病例。其中 2 例为现患病例，2 例为新发病例。基线调查时年龄（岁）、暴露时间（年）、In-S（μg/L）和 KL-6（U/mL）的平均值（范围）分别为 58（50-74）、1.7（0.3-4.8）、3.1（0.3-9.7）和 663（414-942）。从初次铟暴露开始的潜伏期平均为 5.3（0.4-11）年。2 例新发病例的 HRCT 发现为轻度间质/气肿性改变和轻度间质改变。新发病例的标准化发病比（SIR）为 1.89（95%CI 0.52-6.88）。
尽管 SIR 无统计学意义，但由于随访时间短，不足以发现肺癌，且肺癌病例数较少，因此不可否认存在与铟相关的肺癌的可能性。需要进一步随访。
