Enterline P E, Marsh G M
Am J Ind Med. 1980;1(3-4):251-9. doi: 10.1002/ajim.4700010303.
In view of the historic importance of smelter workers in the field of occupational medicine, it is surprising that until very recently little data was available on the mortality experience of these workers. The problem in most studies lies in identifying the smelter workers, because smelting, strictly speaking, refers to the melting of ores for the purposes of recovering metals, whereas smelters sometimes perform the operations of roasting, calcining, sintering, converting, and refining. These distinctions are not made in most mortality studies. Most mortality studies of smelter workers conducted to date have shown some excess in lung cancer. For lead, copper, cadmium, and nickel smelters a different etiologic agent has been proposed for each. These different explanations arise partly from different initial perspectives in conducting the studies. In this paper, data are presented on a current historical-prospective study of males who worked a year or more during the period January 1, 1940 to December 31, 1964 at a copper smelter in Tacoma, Washington. This smelter (and refinery) handled a copper ore with a relatively high arsenic content and produced arsenic trioxide as a by-product. Overall 97.2% of the original study population was traced through 1976. Of the 1,061 who were found to have died, death certificates were obtained for 1,018, or 96%. For all causes of death, the mortality rates in this cohort, expressed as a Standardized Mortality Ratio (SMR), were 3.5% higher than that expected based on the United States white male mortality experience. A total of 104 respiratory system cancers were observed compared to 54.6 expected (SMR = 190.5, p less than .05). Respiratory cancer rates were found to be elevated in both smokers and nonsmokers. Overall, a gradual rise in SMR's for respiratory cancer was observed with increasing duration of exposure but not with an increasing interval from onset of exposure. This observation is consistent with the notion that the effects of arsenic on cancer incidence disappear with time. This phenomenon has also been observed for cigarette smokers and chromate workers. Additional analyses are planned for the Tacoma cohort, which will examine mortality according to process as well as by exposure to arsenic and other contaminants. The importance of studies of workers at other kinds of smelters and refineries is stressed.
鉴于冶炼工人在职业医学领域具有历史重要性，令人惊讶的是，直到最近，关于这些工人的死亡情况的数据仍非常有限。大多数研究的问题在于如何确定冶炼工人，因为严格来说，冶炼是指为回收金属而进行矿石熔炼，而冶炼厂有时还会进行焙烧、煅烧、烧结、转炉吹炼和精炼等操作。大多数死亡率研究并未区分这些操作。迄今为止，大多数针对冶炼工人的死亡率研究都表明肺癌发病率有所增加。对于铅、铜、镉和镍冶炼厂，每种冶炼厂都提出了不同的致病因素。这些不同的解释部分源于开展研究时的不同初始视角。本文展示了一项针对1940年1月1日至1964年12月31日期间在华盛顿州塔科马市一家铜冶炼厂工作一年或更长时间的男性的当前历史前瞻性研究的数据。这家冶炼厂（和精炼厂）处理的铜矿石砷含量相对较高，并将三氧化二砷作为副产品生产出来。到1976年，总体上追踪到了原研究人群的97.2%。在1061名已查明死亡的人员中，获取了1018份死亡证明，占96%。对于所有死因，该队列的死亡率以标准化死亡比（SMR）表示，比基于美国白人男性死亡情况预期的死亡率高3.5%。观察到共有104例呼吸系统癌症，而预期为54.6例（SMR = 190.5，p < 0.05）。发现吸烟者和非吸烟者的呼吸道癌症发病率均有所升高。总体而言，观察到随着接触时间的增加，呼吸道癌症的SMR逐渐上升，但与接触开始后的时间间隔增加无关。这一观察结果与砷对癌症发病率的影响会随时间消失的观点一致。对于吸烟者和铬酸盐工人也观察到了这种现象。计划对塔科马队列进行进一步分析，这将根据工艺以及砷和其他污染物的接触情况来研究死亡率。强调了对其他类型冶炼厂和精炼厂工人进行研究的重要性。
