Cancer incidence among European man-made vitreous fiber production workers.

OBJECTIVES: This study analyzed cancer incidence among man-made vitreous fiber workers. METHODS: A cancer incidence follow-up was conducted among 3685 rock-slag wool (RSW) and 2611 glass wool (GW) production workers employed for > or =1 year in Denmark, Finland, Norway, or Sweden, and the standardized incidence ratios (SIR) were calculated on the basis of national incidence rates. RESULTS: Overall cancer incidence was close to expectation. Lung cancer incidence was increased among the RSW [SIR 1.08, 95% confidence interval (95% CI) 0.85-1.36] and GW (SIR 1.28, 95% CI 0.91-1.74) workers. For both subcohorts, a trend was suggested for time since first employment (P-value for linear trend 0.1 and 0.2, respectively). Neither subcohort showed an association with employment during the early technological phase, when fiber exposure was high. The incidence of oral, pharyngeal, and laryngeal cancer was increased among the RSW (SIR 1.46, 95% CI 0.99-2.07) and the GW (SIR 1.41, 95% CI 0.80-2.28) subcohorts. Despite a trend in risk for these neoplasms among the GW workers with time since first employment, the lack of a positive relation with other indirect indicators of fiber exposure points against a causal interpretation. No association between RSW or GW exposure and the risk of other neoplasms was suggested. CONCLUSIONS: These lung cancer results are similar to those of a mortality study that included a larger number of factories. For other cancers there was no suggestion of an association with RSW or GW exposure.     

Cancer incidence of Nordic asphalt workers

OBJECTIVES: The aim of the study was to investigate cancer risk following employment in the asphalt industry. METHODS :Cancer incidence was studied among 22 362 male asphalt workers employed for more than one season in jobs entailing exposure to bitumen (mainly road pavers) in Denmark, Finland, Norway, and Sweden. These workers are part of a European cohort of asphalt workers, for which results on mortality have been reported. The follow-up was almost complete, and reference rates were obtained from national cancer registries. RESULTS: The incidence of cancer was reduced in all four countries [overall standardized incidence ratio (SIR) 0.89, 95% confidence interval (95% CI) 0.86-0.94]. Lung cancer incidence was increased in all four countries, yielding an overall SIR of 1.21 (95% CI 1.07-1.36), but no trend was detected according to time since first employment. No overall increased incidence of bladder cancer was observed, but there was a suggestion of a tendency towards higher risk with longer time since first employment, with a relative risk of 1.85 (95% CI 0.90-3.78) for more than 30 years versus 1-14 years (P-value for trend 0.1). The incidence of lip and stomach cancer was nonsignificantly increased, and the excess was present mainly in Denmark. No increased incidence was detected for other neoplasms, notably malignant melanoma, nonmelanoma skin cancer, and kidney cancer. CONCLUSIONS: The results of this study confirm the pattern of cancer risk detected in the mortality analysis of the European cohort; in addition, they provide suggestive evidence of an excess risk of bladder cancer among asphalt workers.     

Cancer incidence among creosote-exposed workers.

Cancer incidence was studied among 922 creosote-exposed impregnators at 13 plants in Sweden and Norway. The subjects had been impregnating wood (eg, railroad cross-ties and telegraph poles), but no data on individual exposures were available. The study population was restricted to men employed during the period 1950-1975, and their cancer morbidity was checked through the cancer registries. The total cancer incidence was somewhat lower than expected, 129 cases versus 137 expected [standardized incidence ratio (SIR) 0.94]. Increased risks in both countries combined were observed for lip cancer (SIR 2.50, 95% confidence interval (95% CI) 0.81-5.83), skin cancer (SIR 2.37, 95% CI 1.08-4.50), and malignant lymphoma (SIR 1.9, 95% CI 0.83-3.78). Exposure to sunlight may have contributed to the risk of lip and skin cancer. The small number of cancer cases does not permit valid conclusions. The findings indicate that impregnating wood with creosote in earlier decades increased the risk of skin cancer.     

Cancer incidence among finnish rubber workers

Summary A follow-up study was carried out among workers in the processing and tire and tube fabrication departments of a Finnish rubber plant. A total of 1,331 workers were followed up for cancer through the files of the Finnish Cancer Registry from 1953 to 1976 (11,709 person years). The expected number of cancer cases was calculated on the basis of the age and sex-specific incidence rates for the urban population of the surrounding province. Twenty-one cancer cases were found against 18.9 expected (RR 1.1, 95% confidence interval 0.7–1.7). The risk of cancer of the digestive organs, respiratory organs, and urinary bladder was higher than expected, and the risk increased with the length of the follow-up time. However, the differences were not statistically significant.     

Cancer incidence among Danish stone workers

The lung cancer incidence of 2071 Danish stone workers was followed for a 42-year period. The expected numbers of cancer cases were based on the incidence rates for all Danish men after adjustment for region, and the data were analyzed separately for skilled and unskilled stone workers. The standardized incidence ratio (SIR) for lung cancer was 200 (44 observed, 22.0 expected) for all skilled stone workers, 808 (7 observed, 0.9 expected) for skilled sandstone cutters in Copenhagen, 119 (8 observed, 6.5 expected) for skilled granite cutters in Bornholm, 181 (24 observed, 13.2 expected) for all unskilled stone workers, 246 (17 observed, 6.9 expected) for unskilled workers in the road and building material industry, and 111 (7 observed, 6.3 expected) for unskilled workers in the stonecutting industry. Smoking was unlikely alone to explain the excess risk, and the available data on levels of exposure in the Danish stone industry point to a possible dose-response relationship between exposure to respirable silica dust and the incidence of lung cancer.     

Cancer incidence among alachlor manufacturing workers

A historical cohort study was conducted to evaluate cancer incidence among chemical workers with occupational and environmental exposure to alachlor, the active ingredient in a family of pre-emergent acetanilide herbicides. The study followed 943 workers with at least 1 year of cumulative employment at the Monsanto plant in Muscatine. Iowa, from startup of the alachlor manufacturing process in March 1968 through December 1990. Approximately 96% of all workers were successfully traced to determine their last known residence and cancer status. Eighteen workers were diagnosed with cancer during the follow-up period, based on pathology information from the statewide cancer registry maintained by the State Health Registry of Iowa. The standardized incidence ratio for all cancers was 1.5 (95% CI 0.9–2.4) for all workers exposed to alachlor, which was due primarily to elevated rates for colorectal cancer and chronic myeloid leukemia. Workers with 5 or more years in estimated high alachlor exposure jobs had elevated rates of colorectal cancer (3 cases, SIR = 5.2, 95% CI 1.1–15.1). Interpretation of the study results is limited by the small size of the study population, minimal length of follow-up, and current information concerning alachlor metabolism in primates and humans. Nonetheless, the findings suggest the need for continued evaluation of this and other alachlor-exposed cohorts. © 1996 Wiley-Liss, Inc.     

Cancer incidence among triazine herbicide manufacturing workers

This study evaluated cancer incidence and prostate specific antigen (PSA) testing among workers at a plant in Louisiana (LA) that made atrazine and other triazine herbicides. The study covered the time period 1985 through 1997 and included 2045 subjects, of whom 757 worked for the company that owned the plant and 1288 were contract employees. Linkage with a population-based cancer registry and review of death certificates and plant medical records identified cancer cases. Standardized incidence ratios (SIRs) with 95% confidence intervals (CIs) compared subjects' cancer incidence rates with those of a regional general population. Plant medical records provided data on the proportion receiving PSA tests among male company employees. Subjects had 46 observed and 40 expected cases of all cancers combined (SIR = 114, CI = 83-152) and had 11/6.3 prostate cancers (SIR = 175, CI = 87-312). The prostate cancer excess was greater in actively working company employees (5/1.3, SIR = 394, CI = 128-920) than in contract employees or inactive company employees (6/5.0, SIR = 119, CI = 44-260) and was limited to men under 60 years of age. Of the 11 prostate cancer cases, nine were diagnosed at an early clinical stage. From 1993 to 1999, the proportion of male company employees who had at least one PSA test was 86% for those who reached 40 years of age while actively working and was 98% for those who reached 45 years of age. The observed prostate cancer increase may have been due to the frequent PSA testing of actively working company employees. There is no epidemiologic or other information that clearly supports a causal relation between atrazine and prostate cancer.     

Cancer incidence among Finnish nuclear reactor workers

Because of their well-documented exposures to repeated low doses of ionizing radiation, nuclear reactor workers offer an opportunity to assess cancer risk from low-dose radiation. A cohort of all 15,619 Finnish nuclear reactor workers was established through dose-monitoring records. A questionnaire survey revealed no substantial differences in consumption of tobacco or alcohol between different exposure groups nor between nuclear power company employees and contract workers. In the follow-up for cancer incidence, no clear excess in cancer incidence was observed overall, nor was any observed in any of the specific cancer types studied. There was little evidence for an association between cancer incidence and cumulative radiation dose, but the statistical power was limited. More precise estimates will be available from an international collaborative study of nuclear industry workers, including our cohort.     

Cancer incidence among male Norwegian asphalt workers

BACKGROUND: The main objective of the present study was to investigate whether exposure to bitumen fumes could enhance the risk of cancer in asphalt workers. METHODS: A historical prospective cohort study was performed including 8,763 male asphalt workers from all main asphalt companies in Norway. Name, date of birth, and unique personal identification number, address, job type, and start and stop of employment in specific jobs was obtained for the workers. Information was complied from payroll and personnel records in the companies. The cohort was then linked to the Cancer Registry of Norway, which has complete records of individual cases of cancer in the Norwegian population since 1953. Follow-up was from 1 January 1970 to 31 December 1997. The 5-year age and period adjusted general male population in Norway served as reference population. RESULTS: Lung cancer was found elevated with standardized incidence ratio (SIR) = 1.3 (95% confidence intervals (CI) = 1.1, 1.7) in the overall analysis. Lung cancer was found more elevated in workers first exposed in the 1950s and 1960s and in mastic asphalt workers (SIR = 4.2, 95% CI = 1.2, 10, based on four cases) and pavers (SIR = 1.4, 95% CI = 1.0, 1.9). There was a deficiency in the incidence of malignant melanoma with 13 cases versus 26 expected. CONCLUSIONS: Risk of lung cancer was found enhanced among the asphalt workers. Some of the enhanced risk could probably be explained by the smoking habits of the workers. Exposure to coal tar may also have contributed to the enhanced risk.     

Cancer incidence among Australian nuclear industry workers

To assess whether workers at Lucas Heights Science and Technology Centre (LHSTC) had different levels of cancer incidence from the New South Wales (NSW) population in Australia. A retrospective cohort study was undertaken at LHSTC. Data on 7,076 workers employed between 1957-98 were abstracted from personnel, dosimetry, and medical files. An inception cohort was defined which included 4,523 workers in employment between 1972-96 to examine cancer incidence. Cancer registrations in the inception cohort were identified to 1996 through electronic linkage of records with the NSW and the Australian national registers of cancer incidence. All-cancer incidence in workers at LHSTC was 15% below the NSW rates [SIR=0.85; 95% CI=(0.75, 0.95)]. Of 37 specific cancers and groups of cancers examined, statistically significant excesses relative to NSW rates were observed only for pleural cancer incidence [SIR=17.71; 95%=(7.96, 39.43)], and for incidence of cancer of the small intestine [SIR=4.34; 95% CI=(1.40, 13.46)]. This study gives little evidence of an increased risk of cancers associated with radiation exposure in a cohort of nuclear workers in Australia. The observed increase in the risk of cancer of the pleura was probably due to unmeasured exposures, given the lack of an established association with radiation exposure, and the strong link to asbestos exposure. Findings for cancers of the small intestine were based on small numbers and were likely to be due to chance.     

Cancer incidence among foundry workers in Denmark

Cancer incidence was studied among 6,144 male foundry workers who were invited to participate in either of two Danish national silicosis surveys conducted during 1967-1969 and 1972-1974. Cancer incidence was followed through to the end of 1985 by computerized linkage to the Danish Cancer Registry, and Standardized Morbidity Ratios (SMRs) were calculated based on incidence rates for the Danish population. For the entire cohort, significantly elevated SMRs were seen for all cancers (SMR, 1.09; 95% CI, 1.01-1.18) and lung cancer (SMR, 1.30; 95% CI, 1.12-1.51), and SMRs were at the borderline of statistical significance for bladder cancer (SMR, 1.24; 95% CI, 0.97-1.59). Excess lung and bladder cancer risk were confined to workers who had worked in foundries for at least 20 y. There was a positive correlation between silicosis prevalence in employees at the foundries at the time of the x-ray examinations and lung cancer incidence during the follow-up period. Squamous cell carcinomas, anaplastic carcinomas, and other lung cancers accounted for the excess lung cancer risk, whereas there was not excess risk among the foundry workers for adenocarcinomas of the lung.     

Cancer incidence of workers in a Finnish sawmill

The cancer incidence of 1,223 sawmill workers with continuous employment of at least one year between 1 January 1945 and 31 December 1961 was followed until 31 December 1980. Separate analyses were made for the 801 workers hired after 1 January 1945, and smoking habits were surveyed. Among the men, 90 cases of primary cancer were detected versus 83.5 expected and among the women 55 cancer cases versus 44.5 expected. Skin cancer was in excess among the men, especially among those employed after 1 January 1945. Lip, mouth, and pharynx cancer and lymphomas were also slightly in excess among the men, as was leukemia among both sexes. Workplace exposure, especially to chlorophenols, may be associated with the excess skin cancer and the slight excess of lymphomas, but this finding should be further evaluated with special emphasis on well-defined exposure data.     

Cancer incidence and mortality in aircraft maintenance workers

BACKGROUND: A cancer incidence and mortality study was conducted in response to health concerns raised by workers from F-111 aircraft deseal/reseal fuel tank maintenance programs, to determine whether personnel exposed to deseal/reseal had an excess of cancers and mortality. METHODS: Number of deaths and cancers for individuals involved in F-111 DSRS activities were matched against two Air Force comparison groups. Analyses were weighted to adjust for differences in age, exposure period and rank. RESULTS: Eight hundred seventy-three exposed, 7,577 comparison group one, and 9,408 comparison group two individuals were matched against death and cancer data, with 431 cancers and 431 deaths. Cancer incidence was higher in the exposed group, with marginally significant increases of 40-50% (cancer incidence rate ratio range 1.45-1.62). Exposed group mortality was significantly lower than both comparison groups, likely due to survivor bias in the exposed group (mortality rate ratio range 0.33-0.44). CONCLUSIONS: On the balance of probabilities, there is an increased risk of cancer associated with participation in F-111 deseal/reseal activities.     

Cancer incidence and mortality among Swedish smelter workers

Cancer incidence was analysed in a retrospective cohort of 3710 male Swedish smelter workers between 1958 and 1982 using a record linkage with the Swedish Cancer Register. During this period 467 cancers were registered in the cohort. An excess incidence of total cancer of about 30% was shown relative to general and local populations mainly due to 120 respiratory cancers. Excess SMRs for all cancer and respiratory cancer were highly significant. Trends in the incidence of cancer were studied using moving five year calendar periods. A decreasing rate of lung cancer was found during 1976-80 for both mortality and incidence. Incidence figures for two more years show a continued decreasing trend. This is validated by an analysis of different employment cohorts, taking latency into account, showing that the later the date of first employment the lower the incidence of cancer, especially for lung cancer.     

Cancer incidence among Danish workers exposed to trichloroethylene

Human evidence regarding the carcinogenicity of the animal carcinogen trichloroethylene (TCE) is limited. We evaluated cancer occurrence among 803 Danish workers exposed to TCE, using historical files of individual air and urinary measurements of TCE-exposure. The standardized incidence ratio (SIR) for cancer overall was close to unity for both men and women who were exposed to TCE. Men had significantly elevated SIRs for non-Hodgkin's lymphoma (SIR = 3.5; n = 8) and cancer of the esophagus (SIR = 4.2; n = 6). Among women, the SIR for cervical cancer was significantly increased (SIR = 3.8; n = 4). No clear dose-response relationship appeared for any of these cancers. We found no increased risk for kidney cancer. In summary, we found no overall increase in cancer risk among TCE-exposed workers in Denmark. For those cancer sites where excesses were noted, the small numbers of observed cases and the lack of dose-related effects hinder etiological conclusions.     

Cancer incidence among workers in the Norwegian ferroalloy industry

The total mortality and the incidence of cancer was studied among a cohort of employees at the six oldest ferrosilicon and ferromanganese plants in Norway. The cohort consisted of 6494 men employed for more than 18 months before 1970 and has been followed up from 1953 to 1982. The standardised incidence ratio (SIR) for cancer (all sites) was 0.94. The observed number of cancers was as expected for lung cancer (SIR = 0.99) and for most of the other cancer sites studied. A statistically significant reduction of stomach cancer was found (SIR = 0.72). There was an increased incidence of lung cancer (SIR = 1.75) and cancer of the prostate (SIR = 1.56) in the workers at one ferrosilicon plant and of colonic cancer (SIR = 1.90) at another ferrosilicon plant.     

Cancer incidence among semiconductor and electronic storage device workers

Aims

To evaluate cancer incidence among workers at two facilities in the USA that made semiconductors and electronic storage devices.

Methods

89 054 men and women employed by International Business Machines (IBM) were included in the study. We compared employees'' incidence rates with general population rates and examined incidence patterns by facility, duration of employment, time since first employment, manufacturing era, potential for exposure to workplace environments other than offices and work activity.

Results

For employees at the semiconductor manufacturing facility, the standardised incidence ratio (SIR) for all cancers combined was 81 (1541 observed cases, 95% confidence interval (CI) 77 to 85) and for those at the storage device manufacturing facility the SIR was 87 (1319 observed cases, 95% CI 82 to 92). The subgroups of employees with ≥15 years since hiring and ≥5 years worked had 6–16% fewer total incidents than expected. SIRs were increased for several cancers in certain employee subgroups, but analyses of incidence patterns by potential exposure and by years spent and time since starting in specific work activities did not clearly indicate that the excesses were due to occupational exposure.

Conclusions

This study did not provide strong or consistent evidence of causal associations with employment factors. Data on employees with long potential induction time and many years worked were limited. Further follow‐up will allow a more informative analysis of cancer incidence that might be plausibly related to workplace exposures in the cohort.Epidemiological research on cancer among workers in semiconductor manufacturing and related operations has been limited.^1,2,3,4 During the early years of manufacturing, use of chemicals was intense, and workers'' handling of chemicals was frequent. Various known and suspected carcinogens, including ionising radiation, asbestos, arsenic and arsenical compounds, chromium compounds, sulphuric acid mist, ultraviolet light, trichloroethylene, carbon tetrachloride, nickel and antimony trioxide, have been used in these operations, but information on workers'' exposure to such agents is not available.^4,5,6 Although the potential for workers to be exposed to these agents has declined with the development of engineering controls and with increased use of automated, enclosed processes, concern remains about the possible health effects of past workplace exposures.We recently carried out a mortality study of 126 836 employees at three facilities owned by International Business Machines (IBM).⁷ Two of the facilities, in East Fishkill, New York, USA, and in Burlington, Vermont, USA, made semiconductors, and the third, in San Jose, California, USA, made computer hard drives and other electronic storage devices.⁵ Employees had fewer than expected deaths from all cancers combined and from most specific types of cancer. We found no firm evidence of a causal association between occupational factors and cancer, but several facility‐specific and work activity‐specific subgroups had more than expected deaths from central nervous system, prostate and several other cancers. To obtain a more thorough assessment of potential occupational associations of cancers with relatively long survival,^8,9 we carried out an additional investigation focused on cancer incidence rather than on mortality.The present study evaluated incidence of cancer among employees at the East Fishkill and San Jose facilities in relation to duration of employment, time since first employment and type of work. Because it was not known whether semiconductor workers have been exposed to carcinogenic agents and because previous epidemiological studies have not provided evidence that exposures in the industry are associated with cancer, we did not evaluate hypotheses on specific agents and cancers as part of the present research. We did not include the Burlington facility because linkage with the Vermont cancer registry was not feasible.