Incidence of cancer among anthophyllite asbestos miners in Finland.

A cohort of 736 male and 167 female workers of two anthophyllite mines in Finland was followed up through the Finnish Cancer Registry for cancer in 1953-91. Compared with the total cancer incidence of the east Finnish population, the men had a raised risk of total cancer (standardised incidence ratio (SIR) 1.7; 95% confidence interval (95% CI) 1.4-1.9), mainly attributable to an excess in lung cancer (SIR 2.8; 95% CI 2.2-3.6). The risk of lung cancer was somewhat higher among workers classified as heavily exposed (SIR 3.2; 95% CI 2.4-4.1) than among those moderately exposed (SIR 2.3; 95% CI 1.5-3.6) and the risk increased with increasing smoking and with increasing time of work with exposure. There were four cases of mesothelioma v 0.1 expected, all in men who smoked and had had a long and heavy asbestos exposure. Among women, a non-significant excess in total cancer (SIR 1.5; 95% CI 0.9-2.4) was found in the subgroup with heavy exposure to asbestos. Anthophyllite asbestos seems to have high potency in the carcinogenesis of lung cancer and low potency in carcinogenesis of mesothelioma in comparison with the other types of asbestos.     

Four cases of mesothelioma among Finnish anthophyllite miners.

Four cases of mesothelioma in a cohort of 999 Finnish anthophyllite miners and millers are described. Three deaths were due to pleural mesothelioma and one to peritoneal mesothelioma among the total of 503 male deaths up to 1991. All four patients with mesothelioma had had long term (13 to 31 years) exposure in anthophyllite mining and milling. The latency time from the onset of employment until diagnosis was 39 to 58 years. All four patients were smokers or ex-smokers and had asbestosis. In three of the cases the pulmonary fibre concentration and fibre type were analysed by transmission electron microscopy. High concentrations (270 to 1100 million fibres/g dry tissue) of anthophyllite fibres were detected. The anthophyllite fibres were thicker and had lower aspect ratios than the values reported for crocidolite fibres retained in the lungs of patients with mesothelioma.     

Mortality among lead-zinc miners in Val Seriana

The mortality experience of 1392 lead-zinc-silver miners (Gorno, Northern Italy) employed in the period 1/1/1950-31/12/1980 and followed-up to 31/12/1986 was examined. Two separate estimates of the radon exposure level are available: 0.60 and 0.36 working levels respectively. The silica exposure level was not assessed. Vital status was ascertained for 95.6% of the cohort members and their mortality was compared with expected deaths based on national rates. Significant excess mortality from esophageal cancer, stomach cancer, lung cancer, respiratory tuberculosis, respiratory diseases and deaths from external causes was found among underground miners. Surface workers show significantly increased mortality from liver and bile ducts cancer, hepatic cirrhosis, respiratory tuberculosis and respiratory diseases. Based on the 16.4 excess lung cancer cases among underground miners and their cumulative radon exposure, an attributable risk estimate ranging from 9.78 and 16.31 cases per million person-years and WLM (Working Level Month) was calculated.     

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 among Navajo uranium miners.

OBJECTIVES. To update mortality risks for Navajo uranium miners, a retrospective cohort mortality study was conducted of 757 Navajos from the cohort of Colorado Plateau uranium miners. METHODS. Vital status was followed from 1960 to 1990. Standardized mortality ratios were estimated, with combined New Mexico and Arizona non-White mortality rates used for comparison. Cox regression models were used to evaluate exposure-response relationships. RESULTS. Elevated standardized mortality ratios were found for lung cancer (3.3), tuberculosis (2.6), and pneumoconioses and other respiratory diseases (2.6). Lowered ratios were found for heart disease (0.6), circulatory disease (0.4), and liver cirrhosis (0.5). The estimated relative risk for a 5-year duration of exposure vs none was 3.7 for lung cancer, 2.1 for pneumoconioses and other respiratory diseases, and 2.0 for tuberculosis. The relative risk for lung cancer was 6.9 for the midrange of cumulative exposure to radon progeny compared with the least exposed. CONCLUSIONS. Findings were consistent with those from previous studies. Twenty-three years after their last exposure to radon progeny, these light-smoking Navajo miners continue to face excess mortality risks from lung cancer and pneumoconioses and other respiratory diseases.     

Occupational morbidity among coal miners in the RSFSR]

Analysis of occupational morbidity for 1982-1989 in coal extraction industry workers in the Russian Federation showed its high-level detection in coal-miners. Revealed was a decrease in dust-induced occupational diseases and a greater detection of vibration disease cases, which accounted for 50% in the occupational diseases' structure. In miners, vibration disease cases occurred equally often in coal mine face-workers and driving team workers. The face-workers also exhibited dust-induced diseases and locomotor system disorders. In open pit mines and coal-refining plants, occupational pathology cases were only sporadic. Detectability of occupational morbidity cases was highest in the Rostov Region, Kemerovo, Far-East and Komi coal mines. The performed analysis revealed factors which influence most of all the prevalent forms of occupational pathology, thus laying the basis for the elaboration of health improvement measures.     

Mortality and cancer morbidity in cohorts of asbestos cement workers and referents

Total and cause specific mortality and cancer morbidity were studied among 1929 asbestos cement workers with an estimated median cumulative exposure of 2.3 fibre (f)-years/ml (median intensity 1.2 f/ml, predominantly chrysotile). A local reference cohort of 1233 industrial workers and non-case referents from the exposed cohort were used for comparisons. The risk for pleural mesothelioma was significantly increased (13 cases out of 592 deaths in workers with at least 20 years latency). No case of peritoneal mesothelioma was found. A significant dose response relation was found for cumulative exposure 40 years or more before the diagnosis, with a multiplicative relative risk (RR) of 1.9 for each f-year/ml. No relation was found with duration of exposure when latency was accounted for. There was a significant overrisk in non-malignant respiratory disease (RR = 2.6). The overall risks for respiratory cancer, excluding mesothelioma, and for gastrointestinal cancer were not significantly increased. Surprisingly, colorectal cancer displayed a clear relation with cumulative dose, with an estimated increase of 1.6% in the incidence density ratio for each f-year/ml (but not with duration of exposure).     

广西锡矿工人恶性肿瘤死亡率研究

对大厂和栗木锡矿1972～1974年的在册职工7849人进行了历史前瞻性队列研究;并通过多种监测手段对环境有害因子进行了监测。结果表明,锡矿全死因死亡率为632.7/10万,与全国居民死亡率计算的期望数比较,SMR=1.11(95％CI为1.03～1.19),恶性肿瘤死亡为全死因之首(占39.3％),其次是脑血管疾病和心脏病。恶性肿瘤死亡明显超高(SMR=1.56),且主要集中在肺癌、肝癌和鼻咽癌,其中肺癌占首位(32.1％),SMR为1.98,肝癌和鼻咽癌的SMR为1.79和3.71。监测结果进一步表明,大厂矿肺癌超高与接尘水平及其可吸入砷浓度的高低有明显的联系。     

Mortality from violent causes among the elderly population in Finland in 1951-1979

The changes in violence-related mortality rates among the population aged 65 years or older in Finland from 1951-1979 were studied with the help of the official mortality statistics. Factors underlying these changes were also examined. The most distinctive findings were, first, the increase in accident-related mortality rates of both males and females in the 1950s and, second, the sharp decrease of those rates with respect to women from 1960-1975 compared to the decrease for males during that same period. The changes in mortality for males were mainly due to changes in frequency of motor-vehicle fatalities, whereas the changes for females were mainly due to changes in mortality caused by accidental falls and limb fractures. Improvements in classification methods resulting in the decrease of unspecified causes of death were apparently the main cause of the recorded increase in violent mortality in the early 1950s. The incidence of traffic accidents has decreased in the latter half of the 1970s. Thus, the minor decrease in motor-vehicle accident mortality for men most evidently was due to a decreased incidence. The incidence of hip and limb fractures in women increased. Thus, it was not a lowered incidence but instead a decreased case-fatality rate which caused the decreased mortality in females. Early mobilization after hip operations and decreased dependence level among the elderly apparently resulted in the decreased fatality rates.     

Mortality and cancer morbidity in cohorts of asbestos cement workers and referents.

Total and cause specific mortality and cancer morbidity were studied among 1929 asbestos cement workers with an estimated median cumulative exposure of 2.3 fibre (f)-years/ml (median intensity 1.2 f/ml, predominantly chrysotile). A local reference cohort of 1233 industrial workers and non-case referents from the exposed cohort were used for comparisons. The risk for pleural mesothelioma was significantly increased (13 cases out of 592 deaths in workers with at least 20 years latency). No case of peritoneal mesothelioma was found. A significant dose response relation was found for cumulative exposure 40 years or more before the diagnosis, with a multiplicative relative risk (RR) of 1.9 for each f-year/ml. No relation was found with duration of exposure when latency was accounted for. There was a significant overrisk in non-malignant respiratory disease (RR = 2.6). The overall risks for respiratory cancer, excluding mesothelioma, and for gastrointestinal cancer were not significantly increased. Surprisingly, colorectal cancer displayed a clear relation with cumulative dose, with an estimated increase of 1.6% in the incidence density ratio for each f-year/ml (but not with duration of exposure).     

Mortality among Male Rubber Workers in Finland

The deaths of male rubber workers in two processing departments and a tire and tube manufacturing department of a Finnish rubber plant were studied. The number of person-years at risk was 7,049. Follow-up continued for 24 yr, from January 1, 1953 to December 31, 1976. The total number of deaths was 29 compared with 43 expected (relative risk = 0.7). Only 5 deaths from cardiovascular diseases were found vs. 17.9 expected. The relative risk of death from cancer was 1.0 (7/6.8) and 1.7 (5/2.9) for workers who were exposed for more than 10 yr. For other causes of death the relative risk was not dependent on the length of exposure.     

Mortality from lung cancer among copper miners.

A cohort mortality study of lung cancer in 7088 copper miners was made from 1 January 1969 to 31 December 1988. There was an excess of deaths from lung cancer in the copper miners. The standardised mortality ratio (SMR) was 147 (p < 0.01). The SMR increased with calendar period. There was a higher risk of deaths from lung cancer in the miners employed in the 1950s. Age at the start of exposure had no effect on the risk of lung cancer. The risk of death from lung cancer increased with the duration of exposure and the time since first exposure. The SMR for lung cancer was 173 in underground miners and 193 for drilling miners (both p < 0.01). These data show that exposure to dust is associated with an excess of deaths from lung cancer in copper miners whereas exposure to radiation does not seem to carry such risk.     

Inferences on the kinetics of asbestos deposition and clearance among chrysotile miners and millers

BACKGROUND: The health effects of asbestos are intimately related to the fate of inhaled fibers in the lungs. The kinetics of asbestos fibers have been studied primarily in rodents. The objective of this study was to explore the application of these kinetic models to human autopsy data. METHODS: We analyzed the asbestos fiber content of the lungs of 72 Quebec chrysotile miners and millers and 49 control subjects using analytical transmission electron microscopy. Statistical methods included standard multivariate linear regression and locally weighted regression methods. RESULTS: The lung burdens of asbestos bodies and chrysotile and tremolite fibers were correlated, as were the concentrations of short, medium, and long fibers of each asbestos variety. There were significant associations between the duration of occupational exposure and the burdens of chrysotile and tremolite. The concentration of chrysotile decreased with the time since last exposure but the concentration of tremolite did not. The clearance rate varied inversely with the length of chrysotile fibers. For fibers greater than 10 mu in length the clearance half-time was estimated to be 8 years. CONCLUSIONS: The patterns in our data are compatible with both of the hypotheses suggested from rodent experiments; the existence of a long-term sequestration compartment and overload of clearance mechanisms in this compartment.