Mortality experience of haematite mine workers in China

The mortality risk of iron ore (haematite) miners between 1970 and 1982 was investigated in a retrospective cohort study of workers from two mines, Longyan and Taochong, in China. The cohort was limited to men and consisted of 5406 underground miners and 1038 unexposed surface workers. Among the 490 underground miners who died, 205 (42%) died of silicosis and silicotuberculosis and 98 (20%) of cancer, including 29 cases (5.9%) of lung cancer. The study found an excess risk of non-malignant respiratory disease and of lung cancer among haematite miners. The standardised mortality ratio for lung cancer compared with nationwide male population rates was significantly raised (SMR = 3.7), especially for those miners who were first employed underground before mechanical ventilation and wet drilling were introduced (SMR = 4.8); with jobs involving heavy exposure to dust, radon, and radon daughters (SMR = 4.2); with a history of silicosis (SMR = 5.3); and with silicotuberculosis (SMR = 6.6). No excess risk of lung cancer was observed in unexposed workers (SMR = 1.2). Among current smokers, the risk of lung cancer increased with the level of exposure to dust. The mortality from all cancer, stomach, liver, and oesophageal cancer was not raised among underground miners. An excess risk of lung cancer among underground mine workers which could not be attributed solely to tobacco use was associated with working conditions underground, especially with exposure to dust and radon gas and with the presence of non-malignant respiratory disease. Because of an overlap of exposures to dust and radon daughters, the independent effects of these factors could not be evaluated.     

Mortality experience of haematite mine workers in China.

The mortality risk of iron ore (haematite) miners between 1970 and 1982 was investigated in a retrospective cohort study of workers from two mines, Longyan and Taochong, in China. The cohort was limited to men and consisted of 5406 underground miners and 1038 unexposed surface workers. Among the 490 underground miners who died, 205 (42%) died of silicosis and silicotuberculosis and 98 (20%) of cancer, including 29 cases (5.9%) of lung cancer. The study found an excess risk of non-malignant respiratory disease and of lung cancer among haematite miners. The standardised mortality ratio for lung cancer compared with nationwide male population rates was significantly raised (SMR = 3.7), especially for those miners who were first employed underground before mechanical ventilation and wet drilling were introduced (SMR = 4.8); with jobs involving heavy exposure to dust, radon, and radon daughters (SMR = 4.2); with a history of silicosis (SMR = 5.3); and with silicotuberculosis (SMR = 6.6). No excess risk of lung cancer was observed in unexposed workers (SMR = 1.2). Among current smokers, the risk of lung cancer increased with the level of exposure to dust. The mortality from all cancer, stomach, liver, and oesophageal cancer was not raised among underground miners. An excess risk of lung cancer among underground mine workers which could not be attributed solely to tobacco use was associated with working conditions underground, especially with exposure to dust and radon gas and with the presence of non-malignant respiratory disease. Because of an overlap of exposures to dust and radon daughters, the independent effects of these factors could not be evaluated.     

铁矿工人肺癌回顾性队列研究

对１５个铁矿采矿工人的肺癌进行了回顾性队列研究。队列由１６９５１名１９７１年前入放的男职工组成,观察期从１９８０年至１９８９年,失访７６０人（４．５％）,队列内非接尘人群是接尘人群各群的对照人群。接尘人群及其井下、露天、赤铁矿、磁铁矿各舸矿各组中癌均无明显超量。但接尘人群分为非矽肺和矽肺两群时组,矽肺患者人群的肺癌显示超量。赤铁矿、磁铁矿、井下矿、吴矿各群组都再分为非矽肺和矽肺两群组时,除露天采矿     

Long-term effect of occupational dust exposure

In 1950-1960, a cohort of dust-exposed workers and a cohort of multiple matched unexposed subjects was set up from the files of preventive medical checkups performed in 1,089 Viennese plants. Male workers with a history of long-term exposure to nonfibrous particulates in different industries (metal, ceramics, brick, glass, stone etc.) aged greater than or equal to 40, and male workers without dust exposure (matched for residency, start of observation, age, and smoking) were followed up to 1980 or death (48,960 person yr). By life table methods, dust-exposed workers compared to unexposed workers showed a reduced survival of age 60 (p less than 0.0001), due to lung cancer (123 exposed, 87 controls, p = 0.001), stomach cancer (48/27, p = 0.003), silicosis (40/0), emphysema, bronchitis and asthma (41/23, p = 0.007). No difference in mortality from cardiovascular diseases was observed (p greater than 0.50). We concluded that heavy and long term exposure to respirable particulates is related to increased lung cancer mortality after age 60. A comparison of 2,212 deaths among Austrian silicotics, with deaths in the corresponding population showed a relation between lung cancer and silicosis (p less than 0.001), fairly independent of age and time-period. The estimated relative lung cancer risk of Austrian silicotics in the period 1955-79 averaged 1.41 (95% confidence 1.21-1.64).     

氯乙烯作业工人恶性肿瘤发病情况的流行病学调查

对全国12个城市的13个聚氯乙烯制造工人中5459名氯乙烯作业工人和6461名对照厂工人进行了从投产到1989年12月31日为止的恶性肿瘤发病情况的回顾性和前瞻性队列调查。结果表明,男工接触组肝癌的发病率、死亡率均显著高于对照组,男性肝癌的死亡率也显著高于我国中等城市男性肝癌的死亡率。在恶性肿瘤的分类构成中,接触组男工的肝癌居首位。接触组男工肝癌的发病年龄比对照组显著提前。     

铁矿工人队列死因研究

目的 探索危害铁矿作业工人健康的主要疾患及职业有害因素对工人寿命的影响.方法 用流行病学队列研究方法,对武钢大冶铁矿7 469名职工从1972年开始随访30余年,以全国城市居民年龄别死亡率为参照,用标化死亡比（SMR）作为统计指标,并计算95%可信区间.结果 自1972年至2003年底,共计199 108.0人年,死亡1 752人,累积死亡率为23.5%.影响铁矿工人寿命的主要疾病按累积死亡率从高到低排序分别是：肿瘤（7.8%）、脑血管疾病（3.9%）、心血管系疾病（3.4%）和呼吸系疾病（2.9%）,恶性肿瘤以肺癌和肝癌最多,分别占总死亡数的10%和7.4%.全死因SMR为1.06,高于全国平均水平.死亡率明显升高的疾病有鼻咽癌、肝癌、肺癌、尘肺和意外事故,SMR分别为1.84、1.51、1.83、14.94和1.25.队列中接尘工人与非接尘工人比较,接尘工人全死因、胃癌、肺癌、呼吸系统疾病、心血管疾病和意外事故的累积死亡率明显升高（相对危险度分别为1.35、1.83、1.61、2.27、1.34和1.69）.结论 以粉尘为主的职业有害因素明显影响铁矿工人健康和寿命.     

煤矿区接尘工人30年恶性肿瘤发病情况调查

调查某矿区接尘工人３０年恶性肿瘤的发病情况。方法采用回必队列研究，对该矿区１６７１１名接尘工人和７５９８名非接尘工人恶性肿瘤的发病情况进行调查。结论接尘工人的恶高发，粉尘可能是致病的重要危险因素这一。     

Mortality among sulfide ore miners.

Lung cancer mortality was studied during 1965-1985 in Outokumpu township in North Karelia, where an old copper mine was located. Age-specific lung cancer death rates (1968-1985) were higher among the male population of Outokumpu than among the North Karelian male population of the same age excluding the Outokumpu district (p less than .01). Of all 106 persons who died from lung cancer during 1965-1985 in Outokumpu township, 47 were miners of the old mine, 39 of whom had worked there for at least three years and been heavily exposed to radon daughters and silica dust. The study cohort consisted of 597 miners first employed between 1954 and 1973 by a new copper mine and a zinc mine, and employed there for at least 3 years. The period of follow-up was 1954-1986. The number of person-years was 14,782. The total number of deaths was 102; the expected number was 72.8 based on the general male population and 97.8 based on the mortality of the male population of North Karelia. The excess mortality among miners was due mainly to ischemic heart disease (IHD); 44 were observed, the expected number was 22.1, based on the general male population, and the North Karelian expected number was 31.2 (p less than .05). Of the 44 miners who died from IHD, 20 were drillers or chargers exposed to nitroglycerin in dynamite charges, but also to several simultaneous stress factors including PAHs, noise, vibration, heavy work, accident risk, and working alone. Altogether 16 tumors were observed in the cohort. Ten of these were lung cancers, the expected number being 4.3. Miners who had died from lung cancer were 35-64 years old, and had entered mining work between 1954 and 1960. Five of the ten lung cancer cases came from the zinc mine (1.7 expected). Three of them were conductors of diesel-powered ore trains. The slight excess mortality from lung cancer could be explained by exposure to radon daughters and by the combined effect of silica dust and diesel exhaust gases in the zinc mine.     

Mortality of a cohort of tin miners 1941-86.

The mortality patterns of United Kingdom tin miners were examined in relation to calendar period and duration of underground work with particular attention to lung cancer and exposure to radon. Subjects were all men who had worked for at least one year between 1941 and 1984 at one of two United Kingdom tin mines and for whom a complete work history could be constructed from mine records. Standardised mortality ratios (SMRs) were calculated using national (England and Wales) rates. The pattern of SMRs in relation to potential explanatory variables was analysed using Poisson regression methods. Mortalities from lung cancer and silicosis (including silicotuberculosis) were significantly raised and showed a significant relation with duration of underground work (mortality from stomach cancer was raised in both underground and surface workers, but not significantly). Excess mortality from silica related disease declined steeply from 35% among workers first exposed before 1920 to 1% among those first exposed after 1950. Thirteen surface workers with known exposure to arsenic had high rates of lung and stomach cancer. The SMR for lung cancer showed a consistent pattern in relation to duration of underground exposure, rising from 83 (observed/expected = 8/9.6) for surface workers (without exposure to arsenic) to 447 (15/3.4) for workers with more than 30 years underground exposure. Examination of the SMR for lung cancer by total underground exposure, age, and time since last exposure gave rise to a model for the expression of risk which depends only on total exposure and time since exposure. The fitted model implies that the effect of exposure to radon in a given year has no effect on risk for 10 years, then rapidly rises to a maximum from which the excess risk then declines, halving every 4.3 years. There were no direct measurements of historic radon levels. A conservative estimate based on measurements taken since 1969 by the National Radiological Protection Board and the Mines and Quarries Inspectorate is that the annual dose to an underground worker was about 10 working level months (WLM). Given this assumption, the risk/exposure slope implied by the present data, and the model fitted to it, was somewhat lower than that given in the fourth Committee on the Biological Effects of Ionisation Radiation (BEIR IV) report (about 40% lower for lifetime exposures). The present data also imply different risks depending on the age at exposure, with relatively higher lifetime risks for exposure at older ages, and relatively lower risks for exposures at younger ages. In conclusion, there was a clear relation between exposure to radon and death from lung cancer. The relative risk of lung cancer due to exposure to radon was not constant in cessation of exposure. The lifetime excess risk of lung cancer implied by these data for 40 years exposure at the current statutory limit of four WLM a year starting at age 20, was about 8% (79 excess deaths per 1000 exposed), assuming average smoking habits among the exposed workers. Control of dust concentrations in the mines has substantially reduced--and may have eliminated--direct mortality from silica related disease.     

Mortality of a cohort of tin miners 1941-86

The mortality patterns of United Kingdom tin miners were examined in relation to calendar period and duration of underground work with particular attention to lung cancer and exposure to radon. Subjects were all men who had worked for at least one year between 1941 and 1984 at one of two United Kingdom tin mines and for whom a complete work history could be constructed from mine records. Standardised mortality ratios (SMRs) were calculated using national (England and Wales) rates. The pattern of SMRs in relation to potential explanatory variables was analysed using Poisson regression methods. Mortalities from lung cancer and silicosis (including silicotuberculosis) were significantly raised and showed a significant relation with duration of underground work (mortality from stomach cancer was raised in both underground and surface workers, but not significantly). Excess mortality from silica related disease declined steeply from 35% among workers first exposed before 1920 to 1% among those first exposed after 1950. Thirteen surface workers with known exposure to arsenic had high rates of lung and stomach cancer. The SMR for lung cancer showed a consistent pattern in relation to duration of underground exposure, rising from 83 (observed/expected = 8/9.6) for surface workers (without exposure to arsenic) to 447 (15/3.4) for workers with more than 30 years underground exposure. Examination of the SMR for lung cancer by total underground exposure, age, and time since last exposure gave rise to a model for the expression of risk which depends only on total exposure and time since exposure. The fitted model implies that the effect of exposure to radon in a given year has no effect on risk for 10 years, then rapidly rises to a maximum from which the excess risk then declines, halving every 4.3 years. There were no direct measurements of historic radon levels. A conservative estimate based on measurements taken since 1969 by the National Radiological Protection Board and the Mines and Quarries Inspectorate is that the annual dose to an underground worker was about 10 working level months (WLM). Given this assumption, the risk/exposure slope implied by the present data, and the model fitted to it, was somewhat lower than that given in the fourth Committee on the Biological Effects of Ionisation Radiation (BEIR IV) report (about 40% lower for lifetime exposures). The present data also imply different risks depending on the age at exposure, with relatively higher lifetime risks for exposure at older ages, and relatively lower risks for exposures at younger ages. In conclusion, there was a clear relation between exposure to radon and death from lung cancer. The relative risk of lung cancer due to exposure to radon was not constant in cessation of exposure. The lifetime excess risk of lung cancer implied by these data for 40 years exposure at the current statutory limit of four WLM a year starting at age 20, was about 8% (79 excess deaths per 1000 exposed), assuming average smoking habits among the exposed workers. Control of dust concentrations in the mines has substantially reduced--and may have eliminated--direct mortality from silica related disease.     

High exposure of Chinese mercury mine workers to elemental mercury vapor and increased methylmercury levels in their hair

Objective The aim of this study was to determine the level of exposure of mercury (Hg) miners and smelter workers to elemental mercury (Hg⁰) vapor in China, who work in Hg mines without using protective equipment against Hg⁰ vapor. In addition, the level of methylmercury (MeHg) intake by the workers was estimated from the MeHg concentration in their hair. Methods Urinary total mercury (THg) and hair THg and MeHg concentrations were measured in 26 Hg miners and smelter workers (i.e., exposed group), and 48 unexposed people (unexposed group). Results The exposed group showed high geometric mean THg concentrations in urine (258 ng/ml, 226 μg/g creatinine) and hair (20.0 μg/g). The urinary THg concentration of the smelter workers in particular was extremely high (338 μg/g creatinine in urine). The highest urine THg concentration reached 4577 μg/g creatinine. THg concentrations in urine and hair showed a significant correlation in the exposed group (r=0.62), indicating the adhesion of Hg⁰ vapor to hair. However, no such significant correlation was found in the unexposed group. Hair MeHg concentration in the exposed group (1.97 μg/g) was about threefold higher than that in the unexposed group (0.60 μg/g). Conclusions This study shows that smelter workers in a Chinese Hg mine are exposed to extremely high levels of Hg⁰ vapor, and that Hg miners are exposed to higher levels of MeHg than the unexposed subjects. Further study is needed to determine the cause of the higher hair MeHg concentration in the exposed group.     

Diesel exhaust exposure and mortality among males in the American Cancer Society prospective study

In 1982, the American Cancer Society enrolled over 1.2 million American men and women in a prospective mortality study of cancer and other causes in relation to different risk factors. The 2-year mortality of 461,981 males aged 40-79 years with known smoking habit has been analyzed in relation to exposure to diesel exhaust (DE) and to employment in selected occupations related to DE exposure. The relative risk (RR) for all causes of death for those exposed was 1.05 (95% confidence interval [CI]: 0.97-1.13). For lung cancer, the RR was 1.18 (95% CI: 0.97-1.44). A dose-response effect was present. Railroad workers, heavy equipment operators, miners, and truck drivers had a higher mortality both for all causes and for lung cancer when compared with subjects with other occupations and no exposure to DE. Truck drivers exposed to DE were not at excess risk of lung cancer if compared with truck drivers unexposed to DE, but a trend of increasing risk with duration of exposure was suggested. DE exposure was also associated with increase in mortality for accidents, cerebrovascular disease, arteriosclerosis, and cirrhosis of the liver. An association based on small numbers was also present for Hodgkin's disease and lymphoid leukemia. No association with chronic non-neoplastic pulmonary diseases or with bladder cancer was found.     

Mortality of nitrate fertiliser workers.

An epidemiological cohort study was conducted to investigate the mortality patterns among a group of workers engaged in the production of nitrate based fertilisers. This study was designed to test the hypothesis that individuals exposed to high concentrations of nitrates might be at increased risk of developing cancers, particularly gastric cancer. A total of 1327 male workers who had been employed in the production of fertilisers between 1946 and 1981 and who had been occupationally exposed to nitrates for at least one year were followed up until 1 March 1981. In total, 304 deaths were observed in this group and these were compared with expected numbers calculated from mortality rates in the northern region of England, where the factory was located. Analysis was also carried out separately for a subgroup of the cohort who had been heavily exposed to nitrates--that is, working in an environment likely to contain more than 10 mg nitrate/m3 for a year or longer. In neither the entire cohort nor the subgroup was any significant excess observed for all causes of mortality or for mortality from any of five broad categories of cause or from four specific types of cancer. A small excess of lung cancer was noted more than 20 years after first exposure in men heavily exposed for more than 10 years. That men were exposed to high concentrations of nitrate was confirmed by comparing concentrations of nitrates in the saliva of a sample of currently employed men with control men, employed at the same factory but not in fertiliser production. The men exposed to nitrate had substantially raised concentrations of nitrate in their saliva compared with both controls within the industry and with men in the general population and resident nearby. The results of this study therefore weight against the idea that exposure to nitrates in the environment leads to the formation in vivo of material amounts of carcinogens.     

Occupation and male lung cancer: a case-control study in northern Sweden

Using a case-control study comprising about 600 men with lung cancer in northern Sweden the potential risk of different occupations and groups of occupations was studied. Longitudinal data concerning occupation, employment, and smoking habits were obtained by questionnaires. Some occupational groups (underground miners, copper smelter workers, electricians, and plumbers) exposed to previously known lung carcinogenic agents such as radon daughters, arsenic, and asbestos, had considerably increased odds ratios, which persisted after adjustment for smoking. A slightly raised odds ratio was observed in a group of blue collar workers potentially exposed to lung carcinogenic agents; this rise in the group as a whole mainly disappeared after adjustment for smoking. Farmers and foresters had strikingly low odds ratios, which could only partly be explained by their more moderate smoking habits. The population aetiological fraction attributable to occupation was estimated as 9%.     

Mortality of nitrate fertiliser workers

An epidemiological cohort study was conducted to investigate the mortality patterns among a group of workers engaged in the production of nitrate based fertilisers. This study was designed to test the hypothesis that individuals exposed to high concentrations of nitrates might be at increased risk of developing cancers, particularly gastric cancer. A total of 1327 male workers who had been employed in the production of fertilisers between 1946 and 1981 and who had been occupationally exposed to nitrates for at least one year were followed up until 1 March 1981. In total, 304 deaths were observed in this group and these were compared with expected numbers calculated from mortality rates in the northern region of England, where the factory was located. Analysis was also carried out separately for a subgroup of the cohort who had been heavily exposed to nitrates--that is, working in an environment likely to contain more than 10 mg nitrate/m3 for a year or longer. In neither the entire cohort nor the subgroup was any significant excess observed for all causes of mortality or for mortality from any of five broad categories of cause or from four specific types of cancer. A small excess of lung cancer was noted more than 20 years after first exposure in men heavily exposed for more than 10 years. That men were exposed to high concentrations of nitrate was confirmed by comparing concentrations of nitrates in the saliva of a sample of currently employed men with control men, employed at the same factory but not in fertiliser production. The men exposed to nitrate had substantially raised concentrations of nitrate in their saliva compared with both controls within the industry and with men in the general population and resident nearby. The results of this study therefore weight against the idea that exposure to nitrates in the environment leads to the formation in vivo of material amounts of carcinogens.     

Occupation and male lung cancer: a case-control study in northern Sweden.

Using a case-control study comprising about 600 men with lung cancer in northern Sweden the potential risk of different occupations and groups of occupations was studied. Longitudinal data concerning occupation, employment, and smoking habits were obtained by questionnaires. Some occupational groups (underground miners, copper smelter workers, electricians, and plumbers) exposed to previously known lung carcinogenic agents such as radon daughters, arsenic, and asbestos, had considerably increased odds ratios, which persisted after adjustment for smoking. A slightly raised odds ratio was observed in a group of blue collar workers potentially exposed to lung carcinogenic agents; this rise in the group as a whole mainly disappeared after adjustment for smoking. Farmers and foresters had strikingly low odds ratios, which could only partly be explained by their more moderate smoking habits. The population aetiological fraction attributable to occupation was estimated as 9%.     

中国矿工吸入钍尘后健康效应的研究

目的 研究白云鄂博稀土铁矿接尘矿土长期吸入高浓度含钍稀土矿尘及(气土)的短寿命子体后对矿工健康的影响。方法 采用负高压呼出气中(气土)子体测定装置。结果 流行病学调查表明,接尘矿工肺癌的SM R明显高于对照组的SMR,差别十分显著。结论 首次发现接尘矿工由于长期(30 a以上)吸入高浓度含钍稀土矿尘及(气土)短寿命子体后可以诱发超额肺癌的发生。长期吸烟和采矿现场的γ外照射的协同作用不能排除。     

铬酸盐生产工人肺癌发病情况的流行病学调查研究

对六个地区２５４５名铬酸盐生产工人和５１９７名对照工人的恶性肿瘤发病情况调查结果，铬酸盐生产工人肺癌高发。其男工肺癌的发病和死亡分别占全恶性肿瘤发病和死亡的３５．６３％和３７．５０％；其肺癌的发病率和死亡率分别高达８２．０８／１０万和７９．４３／１０万，均显著高于对照男工（Ｐ＜０．００１）；其肺癌的ＳＭＲ为１．９６７和２．５７１，表明其肺癌死亡率显著高于全国大城市和中等城市男性同年龄组人群的肺癌死亡率；接触铬化物较多的转炉和制造两工种肺癌的发病率分别高达１３１．２１／１０万和７７．２３／１０万，均显著高于对照男工；吸烟与接触铬化物有明显的协同致肺癌作用。     

队列研究中对照组的选择问题

职业流行病学调查时，对照组是非常重要的，因为使用不同折对照组将得到不同的结果。为了选择一个较好的有可比性的对照组，本文调查了某煤矿工人死亡率，调查对象共２５８９例生矿工，追踪２１年（１９７２年１月１日￣１９９２年１２月３１日），采用５个对照组，即内对照、工厂组、３个居民组（当地、某城区和全国）进行分析，探讨队列研究中如何选择恰当对照，使其结果更能反映客观事实。结果表明：不同对照其结果不同。分析了各