Epidemiologic studies of Scottish oil shale workers: I. Prevalence of skin disease and pneumoconiosis

In an epidemiologic study of 6,359 oil shale workers, 1,664 (46.7%) of 3,566 survivors were investigated. No excess of skin disease (as reported in response to a questionnaire) was found in men exposed to oil or dust, whether compared to men who were not exposed to oil or dust or to coalminers. A low prevalence of simple pneumoconiosis was found in workers exposed to dust, while progressive massive fibrosis occurred in approximately 1% of miners and retort workers. Comparisons of responders with nonresponders revealed no serious bias in terms of age or work experience, though nonresponders were likely to have been less healthy in general.     

Epidemiologic studies of Scottish oil shale workers: II. Lung function in shale workers' pneumoconiosis

In a case control study of 122 ex-shale workers, half of whom had simple pneumoconiosis and half of whom did not, those with pneumoconiosis were found to have the poorer lung function. Significant reductions in forced expiratory capacity (FEV1), forced vital capacity (FVC), Vmax50, lung volumes, and carbon monoxide transfer were found in men with pneumoconiosis. It is suggested that these abnormalities may represent a mixture of pulmonary fibrosis and airways obstruction related to exposure to dust and fumes in shale mines and at shale retorts.     

Mortality among rubber workers: IX. Curing workers

This research examined mortality among 1,152 white male production workers employed in the tire-curing department of a large rubber manufacturing plant. To determine whether these men had any cause-specific mortality excesses, their experience was compared with that of both the U.S. white male general population and a group of production workers at the same plant who had not worked in the curing division. Both types of comparisons indicated that the curing workers experienced excess mortality from lung cancer. There were 45 deaths from lung cancer among curing workers compared to 24.6 expected based on the age- and calendar period-specific rates of other rubber workers. In addition, the mortality rate ratio for pneumonia was 2.2 for curing relative to noncuring workers. These findings are consistent with the results of other studies and suggest that occupational exposures may have contributed to the development of pulmonary disease among curing workers.     

Causes of death among workers in a bearing manufacturing plant

Recent studies identify digestive cancer excesses among workers exposed to cutting fluids, abrasive dusts, and oil smoke. Standardized proportional mortality and mortality odds ratio studies were carried out for a ball bearing plant. Cause of death and work histories were obtained for 702 of 768 hourly employees with ten or more years' service who died between 1969 and 1982. Union and company records were used to define exposure measures. The major findings were significant excesses in proportional mortality ratios (PMR) from stomach cancer (PMR = 2.0) and rectal cancer (PMR = 3.1) among white men. After control for age at death, there was a significant association between stomach cancer and precision grinding exposures, consisting primarily of direct contact with water-based cutting fluids (usually emulsified oils) and their aerosols. Some straight oils and synthetic cutting fluids were used as well. The pattern of stomach cancer is consistent with previous findings and suggests an association with the soluble oil cutting fluids.     

Epidemiologic studies of cancer in agricultural workers

The incidence of cancer in agricultural workers is generally low, in part due to the low prevalence of cigarette smoking in this group. However, agricultural workers have elevated risks for several specific cancer types including leukemia, Hodgkin's disease, non-Hodgkin's lymphoma, multiple myeloma, and cancers of the lip, stomach, prostate, brain, and connective tissue. Two major groups of risk factors have been proposed as causes of hematologic malignancies in agricultural workers. The first group includes various agricultural chemicals. In particular, several studies have found increased risks of malignant lymphoma and soft tissue sarcoma in persons exposed to phenoxy herbicides. However, the evidence is inconsistent and there is a wide variation in relative risk estimates. The second group of risk factors includes various animal viruses. There is currently little evidence concerning the zoonotic nature or human carcinogenicity of these viruses. However, leads have been suggested by recent evidence of increased risks of hematologic malignancies in abattoir workers, veterinarians, and meat inspectors. A third hypothesis, for which little evidence is currently available, is that agricultural work may involve prolonged antigenic stimulus leading to lymphoproliferation. The factors responsible for the increased risks for cancers other than hematologic malignancies are not well understood but may also involve exposure to chemicals or viruses.     

Epidemiologic study of cancer mortality among Israeli asphalt workers

BACKGROUND: We describe the results of a cancer mortality study among asphalt workers in Israel. METHODS: Personal identifiers and employment histories of 2,176 workers were extracted from company records. RESULTS: Mortality from all malignant neoplasms was significantly reduced in the whole cohort (SMR 0.68, 95% confidence interval (CI) 0.56-0.83). SMR for lung cancer was elevated in workers exposed to bitumen (SMR 1.05, 95% CI 0.62-1.66). No significant elevation or reduction in mortality was observed in relation to a specific site. SMRs for lung cancer was higher among ever exposed to bitumen than among unexposed. There was no association between lung cancer risk and estimated exposure to bitumen fume, and no dose-response was apparent. CONCLUSIONS: While the results of this cohort study indicate a slightly increased SMR for lung cancer, it did not produce evidence of a causal link between lung cancer and exposure to bitumen fume.     

Mortality in employees of a Scottish paper mill

To assess possible health risks associated with the manufacture of paper, we carried out a retrospective analysis of mortality among 4,242 men and women employed at a Scottish paper mill between 1955 and 1992. During follow-up to 1994, 959 subjects had died giving an SMR of 0.85 (95% CI 0.80–0.90) in comparison with the national population. Mortality from all cancer (SMR 0.77, 95% CI 0.68–0.88) and particularly from lung cancer (SMR 0.64, 95% CI 0.50–0.81) was lower than expected. An excess of lymphatic and hematopoietic cancer (11 deaths, SMR 2.17) was observed in the making department. These findings do not support an occupational hazard of lung cancer as suggested by several earlier studies. The excess of lymphatic and hematopoietic cancer in the making department was unexpected, and may be a chance occurrence. Am. J. Ind. Med. 32:535–539, 1997. © 1997 Wiley-Liss, Inc.     

Influence of age at death on accuracy of death certificate disease diagnosis: findings in 475 consecutive deaths of mesothelioma among asbestos insulation workers and asbestos factory workers.

Age at death had no appreciable influence on accuracy of death certificate diagnoses of 475 consecutive deaths of mesothelioma among asbestos insulation and asbestos factory workers, until age 75 or older.     

Occupational and environmental health problems of the developing oil shale industry: a review

The American oil shale industry is on the threshold of commercial industrial development. Potential occupational hazards include shalosis or oil shale pneumoconiosis, dermatoses, cancer of the skin, lung, and possibly other sites, and accidents. Air, water, and solid waste pollution problems are complicated by the aridity of the Green River oil shale formation located in Utah, Colorado, and Wyoming. The region currently lacks the schools, health facilities, community services, and skilled labor required for large-scale development. The oil shale industry faces an opportunity and a challenge of prudently assessing and controlling exposures and contributing to the social development of the region.     

Mortality among rubber workers: VIII. Industrial products workers

This report compares the mortality experience of 6,533 men employed in the industrial products division of a rubber manufacturing company with that of U.S. males and of other rubber workers. For most causes of death the mortality rates of industrial products workers were lower than those of U.S. males and similar to those of other rubber workers. Relative to other rubber workers, men in the industrial products division had a 50% excess of deaths from lymphoma, a 90% excess of deaths from multiple myeloma, and a 20% excess of deaths from bladder cancer during the study period. The excesses of lymphoma and multiple myeloma were strongest during recent follow-up in 1970–78 (observed/expected deaths: 10/4.3 for lymphoma; 10/4.4 for multiple myeloma), whereas bladder cancer mortality was not excessive during this calendar period.     

A follow-up study of agricultural chemical production workers.

This retrospective follow-up study evaluated the mortality experience of 4,323 men employed at a plant in Alabama (AL) that manufactures agricultural and other chemicals. On average, there were 18 years of follow-up per subject during the study period of 1951 to 1987. The observed numbers of deaths among cohort members were compared with the numbers expected on the basis of United States (US) and AL general population mortality rates. The all causes standardized mortality ratio (SMR), computed using US rates as the referent, was 97 (233 observed/240 expected deaths) for whites and 68 (47/69) for blacks. White subjects had more than expected deaths from buccal cavity and pharynx (BCP) cancer [SMR = 388; 95% confidence interval (CI) = 125-905] and from esophageal cancer (SMR = 417; 112-1,067). Their lung cancer mortality rate was 50% higher than the rate of US white men and 14% higher than the rate of AL white men. Each of these three cancers has strong nonoccupational determinants, the roles of which were not assessed and which may have been responsible in whole or in part for the observed increases. The excesses of lung and esophageal cancer were concentrated among short-term employees, an observation which also argues against a causal link with occupational factors. Black men experienced no increased mortality from BCP, esophageal or lung cancer, but results for blacks were imprecise. For white and black subjects combined, there were 3 observed versus 0.62 expected deaths due to soft tissue sarcoma (p = 0.05). The job histories of subjects with this type of cancer did not suggest any shared occupational exposure.     

Lung cancer risk in past asbestos workers a few decades after exposure cessation and prospects for screening

To ascertain whether the current risk of lung cancer in former asbestos workers was higher than in the general population, 1,557 past asbestos workers were recruited during statutory health examinations (from 2000 onward) and followed up for mortality. Standardized mortality ratios (SMRs) were calculated. Poisson regression was used to adjust the rate ratios (RRs) for confounders. SMR was about 1.00 in workers with or without pleural plaques and 4.62 (95% confidence interval: 0.61–18.1) in those with asbestosis. Adjusted RRs for lung cancer were 4.70 (0.99–22.5) for asbestosis, 4.35 (0.97–19.5) for former smokers, 6.82 (1.38–34.4) for current smokers. Currently, lung cancer mortality in past asbestos workers is similar to the general population, probably because workers more exposed /more susceptible could have died from lung cancer before the beginning of follow-up.     

Update of a study of crude oil production workers 1946-94

OBJECTIVE—To update information on workers in the petroleum industry engaged in the production of crude oil to determine whether the patterns of mortality have changed with 14 additional years of follow up.
METHODS—All workers were employed at company production and pipeline locations sometime during 1946-94. The cohort now consists of 24 124 employees with an average of 22 years of follow up.
RESULTS—The overall mortality, and most cause specific mortalities were lower than or similar to those for the general United States population. For white men (81% of the cohort), there were 4361 observed deaths and 5945 expected, resulting in a significantly lower standardised mortality ratio (SMR) of 73. There were significant deficits for all the leading causes of death in the United States including all cancers, cancer of the lung, stroke, heart disease, respiratory disease, and accidents. Slightly increased mortality was found for cancer of the prostate, cancer of the brain and central nervous system, and cancer of other lymphatic tissue. For benign and unspecified neoplasms, the SMR was 152 (95% confidence interval (95% CI) 95 to 230). There was a significant increase for acute myelogenous leukaemia that was restricted to people who were first employed before 1940 and who were employed in production and pipeline jobs for >30 years. Overall mortality patterns for non-white men and women were similar to those for white men. Mortality patterns for white men were also examined by duration of employment, time first employed, and by job group.
CONCLUSIONS—The results of the updated study showed a favourable mortality experience for crude oil production workers compared with the United States population.


Keywords: petroleum industry; occupational cancer; mortality; crude oil     

The mortality of coke workers in Britain

Two studies of coke workers in Britain, comprising 6,767 men, gave similar results. The proportion of lung cancer deaths was about 20% higher than in manual workers generally. The excess occurred primarily among younger men. The ratio of lung cancers to all other cancers was also higher than expected, with limited data showing no evidence of excessive tobacco consumption. Death rates from other causes were generally favorable. Overall the lung cancer death rates in oven workers were similar to those in non-oven men, but in both studies some indications of a job-specific excess were noted. These findings are compared with results from earlier studies in the United States and Canada where a much higher excess lung cancer mortality was found in oven men, particularly those with longer exposure times. We discuss possible reasons for the differences, and conclude that the results reported now contribute further evidence that exposure to coal carbonization fumes can cause lung cancer.     

A mortality study of cobalt production workers: An extension of the follow-up

The follow-up of a cohort of workers employed in an electrochemical plant producing cobalt and sodium, previously studied from 1950–1980, has been extended from 1981–1988. The standardized mortality ratio (SMR) for all causes of death was 0.85 (95% confidence interval [CI] + 0.76–0.95, 309 observed) for the whole cohort, and 0.95 (95% CI + 0.83–1.08, 247 observed) for the subcohort of workers born in France. With regard to lung cancer mortality among cobalt production workers, which is the main objective of the study, the SMRs were, respectively, 0.85 (95% CI + 0.18–2.50, 3 observed) and 1.16 (95% CI + 0.24–3.40, 3 observed). Neither did any excess of mortality from diseases of the circulatory and of the respiratory systems appear among cobalt production workers. Maintenance workers, however, exhibited high SMRs for lung cancer, reaching statistical significance for duration of exposure and time since first exposure ≥ 30 years. This study does not support the hypothesis of a relationship between lung cancer and cobaltexposure. © 1993 Wiley-Liss. Inc.     

卷烟生产工人十年死亡原因回顾性调查

本文对178例卷烟生产死亡工人,以6313例当地居民死亡病例为对照进行了十年(1981年1月1日至1990年12月31日)死亡原因回顾性调查。结果发现,卷烟生产女工平均死亡年龄比当地女性居民提前5.65岁。卷烟生产女工恶性肿瘤和呼吸系统疾病的死因序位分别提前1个位次,SMR分别为170和193,与对照组比有显著性意义(P<0.05)。卷烟生产女工肠癌和乳腺癌的死因序位与居民比分别提前5和6个位次,SMR分别为512和592(P<0.05)。本次调查未发现男性卷烟工人死因与当地居民存有差异。     

Mortality in a cohort of antimony smelter workers

Animal studies show that antimonymay cause lung cancer and heart and lung disease in rodents. In exposed humans, ECG abnormalities and heart and lung disease have been reported. This mortality study of 1,014 men employed between 1937 and 1971 in a Texas antimony smelter consisted primarily of workers of Spanish ancestry (n = 928, 91.5%). Hispanics are known to smoke at much lower rates than non-Hispanics, and their lung cancer and heart disease mortality is generally low. When ethnic-specific Texas lung cancer death rates were used for comparison, mortality from lung cancer among antimony workers was elevated (SMR) 1.39, 90% CI 1.01-1.88), and we observed a significant positive trend in mortality with increasing duration of employment. When ischemic heart disease death rates from three different Spanish-surnamed populations were used for comparison, the rate ratios for mortality from ischemic heart disease were 0.91 (90% CI 0.84-1.09), 1.22 (90% CI 0.78-1.89), and 1.49 (90% CI 0.84-2.63). Pneumoconiosis/ other lung disease death rates for Spanish-surnamed men were unavailable and so calculation of rate ratios used white males as a comparison population (SMR 1.22; 90% CI 0.80-1.80). These data suggest some increased mortality from lung cancer and perhaps nonmalignant respiratory heart disease in workers exposed to antimony. However, conclusions are limited by possible confounders and the difficulty of identifying appropriate referent groups.     

Causes of death in Huntington disease as reported on death certificates

Huntington disease (HD) is a late onset autosomal dominant neurological disorder. Two hundred fifty-three death certificates of HD-affected individuals from four midwestern states were examined to determine the completeness of reporting HD on the death certificates. Overall, 66% of death certificates indicated HD as a primary or contributory cause of death. There was significantly better reporting on more recent death certificates, but even since 1979, 16% did not report HD. The implications to those researching HD family histories and to the accuracy of mortality rates are discussed.