Testicular cancer among Swedish pulp and paper workers

BACKGROUND: The incidence of testicular cancer has increased in recent decades. The aims of the present study were to elucidate whether Swedish paper and pulp mill workers had an increased incidence of testicular cancer, and to investigate whether certain occupational groups within the pulp and paper mill workforce were at increased risk. METHODS: The study was based on the Swedish Cancer Environment Register, which links the incidence of cancer for the period 1971-1990 with 1960 and 1970 National Census data on specific industries and occupations for all employed subjects in Sweden. RESULTS: Among maintenance workers employed both in 1960 and in 1970 in paper mills there was an increased risk for testicular cancer (standardized incidence ratio (SIR) 7.4, 95% confidence intervals (CI) 1.5-22), especially for seminomas (SIR 10.1, 95% CI 2.1-29). Maintenance workers were also at increased risk when analyzing workers employed in 1960, 1970, or both years. CONCLUSIONS: This study indicates an increased risk for testicular cancer, especially seminomas, among maintenance workers, but not among process workers, in Swedish paper mills.     

Cohort cancer incidence among pulp and paper mill workers in British Columbia.

OBJECTIVES: A study was conducted to investigate cancer risks in a cohort of pulp and paper workers. METHODS: All male workers with > or =1 years of employment in 14 pulp and paper mills in 1950-1992 were studied. Standardized incidence ratios (SIR) were used to compare the cancer incidence of the cohort with that of the Canadian male population. Record linkage with the National Cancer Registry was performed using the generalized iterative record linkage method. RESULTS: Altogether 1756 cancer cases were observed in the entire cohort. For > or =15 years of work, the entire cohort had significantly increased SIR values for pleural and prostate cancer and skin melanoma; there was also a significantly increased risk for skin melanoma among workers in the kraft process only, rectal cancer among workers in the sulfite process only, and stomach and prostate cancer and all leukemias combined among workers in both the kraft and sulfite processes. A separate analysis comparing workers in pulping and papermaking with those in the pulping process only did not reveal any difference in cancer risk and hence did not modify the results. The SIR values for skin melanoma were not significantly increased in a comparison using the British Columbia male population. Nine of 10 pleural cancers were mesotheliomas, which likely reflect past asbestos exposure. CONCLUSIONS: The results suggest that long-term work in the pulp and paper industry is associated with excess risks of prostate and stomach cancers and all leukemias for work in both kraft and sulfite processes and of rectal cancer for work in the sulfite process only.     

Risk of lung cancer among former chromium smelter workers

Hexavalent chromium is a known carcinogen. Previous epidemiologic studies in the 1950s of United States workers from seven facilities producing chromium compounds from chromite ore have reported a markedly increased risk for dying from lung cancer. As part of a high risk notification project of workers from four of these facilities, a mortality study was performed. The cohort was assembled in 1990–1991 from the Social Security records of four former chromate producing facilities in northern New Jersey. The study subjects were known to have worked at these facilities some time between 1937 and 1971. Proportionate mortality and proportionate cancer mortality ratios (PCMR) were calculated. The overall risk for lung cancer was a PCMR of 1.51 (confidence limits [CL] 1.29–1.74) for white men and 1.34 (CL 1.00–1.75) for black men. These risks increased with increasing duration of employment and latency since time of first employment. The PCMR for greater than 20 years duration of work and more than 20 years since first exposure was 1.94 (CL 1.15–3.06) for white men and 3.08 (CL 1.13–6.71) for black men. The risk for lung cancer for white men remains elevated more than 20 years after exposure has ceased (PCMR, 1.29; CL 1.03–1.60). The PCMR for nasal cavity/sinus cancer was also found to be a significantly increased, 5.18 (CL 2.37–11.30). A cluster of bladder cancer was seen among black workers from one facility, (PCMR, 3.30; CL 1.42–6.51). Despite the cessation of exposure, former chromium workers remain at significantly increased risk of lung cancer. Although there have been case reports of nasal cavity/sinus cancer in association with chromium exposure, this is the first epidemiologic study to report a significant increase in these cancers. Limitations in this study include lack of exposure data and lack of information on smoking habits. The lack of increase in other smoking-related diseases besides lung cancer indicates that the increase in lung cancer cannot be attributed to cigarette smoking. The ongoing elevated risk of lung cancer after cessation of exposure emphasizes the need for developing early detection tests for lung cancer. © 1996 Wiley-Liss, Inc.     

Organic dust exposure and work-related effects among recycling workers

OBJECTIVE: Organic dust exposure and work-related symptoms and effects among household waste recycling workers in Materials Recovery Facilities (MRFs) are a concern. MRFs are a central operation where source-segregated, dry, recyclable materials (paper, plastics, cans, etc.) are sorted, mechanically or manually, to market specifications for processing into secondary materials. METHODS: One hundred and fifty-nine MRF workers (91%) from nine MRFs participated. Measurements of airborne total dust, endotoxin, (1-->3)-beta-D-glucan, and a questionnaire survey were carried out. Blood data was restricted to MRFs 3, 6, and 9 (45 workers). Blood sampling investigated differential cell counts, erythrocyte sedimentation rate (ESR), and immunoglobulin (Ig)E. RESULTS: Workers exposed to higher amounts of endotoxin and (1-->3)-beta-D-glucan had an increased risk for respiratory symptoms as compared to those with lower exposure. Stomach problems was associated to higher (1-->3)-beta-D-glucan exposure. MRF 3 had a higher (1-->3)-beta-d-glucan exposure compared to 6 and 9, and respiratory symptoms, unusual tiredness, and vomiting were reported more often in MRF 3. Monocyte numbers and ESR were significantly decreased in MRF 3 compared to MRF 6 and 9, but all measured values were within normal ranges. CONCLUSIONS: The results suggest that MRF workers exposed to higher levels of endotoxin and (1-->3)-beta-D-glucan at their work sites exhibit various work-related symptoms, and that the longer a worker is in the MRF environment, the more likely he is to become affected by various respiratory and gastrointestinal symptoms.     

Assessment of exposure in an international study on cancer risks among pulp,paper, and paper product workers

A data management system and a department-exposure matrix (PAPDEM) was designed and constructed to facilitate exposure assessment for a large multinational study on cancer risks among pulp, paper, and paper product workers. Exposure to 25 major agents was described by prevalence, P (i.e., proportion of the exposed, classified %-range), and level, L (i.e., annual mean concentration at work, classified). Some agents could be assessed only in qualitative terms. The assessment was specific to mill, work department, agent, and time period. The results of industrial hygiene measurements, information from detailed company questionnaires, and the professional judgments of the assessment team were the cornerstones of the assessment. Validity and consistency of the assessment were aimed at by setting default values for P and L prior to the assessment, accurately defining agents and exposure classes, dividing assessment work by subindustry, working in pairs, testing interrater agreement, and finalizing the estimates in a meeting. In spite of these precautions, good agreement between different assessors was difficult to reach. Exposure to chemical agents turned out to be widespread and complex with frequent multiple exposures. A computer-assisted exposure assessment system such as PAPDEM may save time and facilitate assessment in large epidemiological studies requiring complicated exposure assessment procedures. It also provides a good documentation of exposure assignments, which may be useful in the interpretation of the results and in future updates of the study.     

Mortality among pulp and paper workers in Berlin, New Hampshire.

Cause specific mortality was analysed among 883 white male workers from a paper company in Berlin, New Hampshire. Subjects were assigned to different exposure groups on the basis of their having worked in the pulp mill, the paper mill, or elsewhere in the paper company. A standardised mortality ratio (SMR) analysis was used to compare death rates for each of the exposure groups with United States national rates. For all the subjects, deaths due to all causes, all malignant neoplasms, and lung cancer were close to the number expected and excesses were noted for cancers of the digestive system and leukaemia. Among pulp mill workers, the number of cancers of the digestive system was raised and the SMR for pancreatic cancer was especially high (SMR = 305, 95% CI = 98-712). Among paper mill workers, more deaths were due to leukaemia and cancers of the digestive system than expected. These results are consistent with the findings from other studies that employment in pulp and paper mills is associated with excess mortality due to digestive and lymphopoietic cancers.     

Mortality and cancer morbidity among cement workers.

OBJECTIVE--To explore associations between exposure to cement dust and cause specific mortality and tumour morbidity, especially gastrointestinal tumours. DESIGN--A retrospective cohort study. SUBJECTS AND SETTING--2400 men, employed for at least 12 months in two Swedish cement factories. MAIN OUTCOME MEASURES--Cause specific morality from death certificates (1952-86). Cancer morbidity from tumour registry information (1958-86). Standardised mortality rates (SMRs; national reference rates) and standardised morbidity incidence rates (SIRs; regional reference rates) were calculated. RESULTS--An increased risk of colorectal cancer was found > or = 15 years since the start of employment (SIR 1.6, 95% confidence interval (95% CI) 1.1-2.3), mainly due to an increased risk for tumours in the right part of the colon (SIR 2.7, 95% CI 1.4-4.8), but not in the left part (SIR 1.0, 95% CI 0.3-2.5). There was a numerical increase of rectal cancer (SIR 1.5, 95% CI 0.8-2.5). Exposure (duration of blue collar employment)-response relations were found for right sided colon cancer. After > or = 25 years of cement work, the risk was fourfold (SIR 4.3, 95% CI 1.7-8.9). There was no excess of stomach cancer or respiratory cancer. Neither total mortality nor cause specific mortality were significantly increased. CONCLUSIONS--Diverging risk patterns for tumours with different localisations within the large bowel were found in the morbidity study. Long term exposure to cement dust was a risk factor for right sided colon cancer. The mortality study did not show this risk.     

Renal cell cancer among paperboard printing workers.

A physician's alert prompted us to investigate workers' cancer risk at a paperboard printing manufacturer. We conducted a retrospective cohort mortality study of all 2,050 persons who had worked at the facility for more than 1 day, calculated standardized incidence ratios (SIRs) for bladder and renal cell cancer, and conducted a nested case-control study for renal cell cancer. Standardized mortality ratios (SMRs) from all causes [SMR = 1.0, 95% confidence interval (CI) = 0.9-1.2] and all cancers (SMR = 0.6, 95% CI = 0.3-1.0) were not greater than expected. One bladder cancer and one renal cell cancer were included in the mortality analysis. Six incident renal cell cancers were observed, however, compared with less than two renal cell cancers expected (SIR = 3.7, 95% CI = 1.4-8.1). Based on a nested case-control analysis, the risk of renal cell cancer was associated with overall length of employment but was not limited to any single department or work process. Although pigments containing congeners of dichlorobenzidine and o-toluidine had been used at the plant, environmental sampling could not confirm any current exposure. Several limitations and a potential selection bias limit the inferences that can be drawn.     

Cardiovascular mortality among Swedish pulp and paper mill workers

BACKGROUND: Malignant diseases but also cardiovascular and respiratory disorders and diabetes mellitus have been associated with work in pulp and paper production. The present cohort focuses on cardiovascular mortality in relation to various exposures in this industry. METHODS: The cohort, followed-up for mortality, includes 7,107 workers, 6,350 men and 757 women, from three major old mills in the middle of Sweden. RESULTS: Instead of a healthy-worker effect, a slightly increased risk for death in diseases of the circulatory system was found for male workers. Notably, work with sulfate digestion, steam and power generation and maintenance was associated with significantly increased risks. Cerebrovascular diseases showed non-significantly increased risks for maintenance and paper and paperboard production and manufacture. CONCLUSIONS: The differences in risk among various parts of the production are striking although it is hard to pinpoint any specific exposures. Dust and small particles along with sulfur compounds might be suspected.     

Mortality among production workers in pulp and paper mills

A cohort of 3,572 pulp and paper mill workers employed for at least one year between 1945 and 1955 was followed through 31 March 1977. Vital status was determined for 99% of the cohort. The 915 deaths observed were 79% of the number expected on the basis of comparable United States mortality rates. Statistically nonsignificant excesses of deaths due to lymphosarcoma and reticulosarcoma and to stomach cancer were observed. These findings tend to corroborate reports based on state vital statistics, and preliminary case-referent and population-based studies of workers in the pulp or paper industries. No deaths due to nasal cancer were observed, but only 0.6 were expected. When process-specific analyses were conducted, the excess risk of lymphosarcoma and reticulosarcoma was increased only for men who worked in sulfate mills. The excess risk of stomach cancer was limited to men who worked in sulfite mills. Process-specific standardized mortality ratios for these causes were highest after 20 years since first employment in the mills.     

Nasal symptoms among workers exposed to soft paper dust

Objectives: To clarify whether occupational exposure to paper-dust is associated with an increased risk of non-infectious rhinitis. Methods: Thirty-seven workers exposed to paper-dust in a soft-paper mill were compared with 36 unexposed controls. The study was performed under normal working conditions during the non-pollen season. Medical and occupational history was taken down in a comprehensive questionnaire and nasal symptoms were scored on a visual analogue scale (VAS). Pulmonary and nasal function was assessed by spirometry, acoustic rhinometry and peak nasal inspiratory flow. Nasal lavage was analysed for interleukin-8 (IL-8) and nasal transit time was monitored with the saccharine test. Concentrations of inhalable dust for each exposed subject during the day of the clinical study were measured with personal sampling devices. Results: There was an increased prevalence of nasal blockage and crust formation among the exposed workers. However, there was no difference with regard to acoustic rhinometry, nasal transit time or nasal peak inspiratory flow. In the whole population, IL-8 in nasal lavage was higher among men than among women, 193 ng/l vs 132 ng/l, P=0.006. There was also a positive trend (P=0.01) with increasing nasal IL-8 going from non-smokers (122 ng/l), ex-smokers (126 ng/l) to current smokers (235 ng/l). Conclusions: We have found that occupational exposure to paper-dust is associated with symptoms of nasal blockage and nasal crusting. We find no objective signs of nasal inflammation, even among the subgroup with the highest current exposure. Received: 13 March 2000 / Accepted: 5 August 2000     

Risk of suicide among cancer patients.

Of the 28,857 cancer cases registered by the Finnish Cancer Registry in 1955, 1960 and 1965, 63 patients had committed suicide by the end of 1970. The suicide rate among males was 1.3 times higher (p less than 0.01) and among females 1.9 times higher (p less than 0.05) than the rate in the general population. The highest suicide risk (relative risk 2.5, p less than 0.001) was associated with gastrointestinal cancer. Patients with a non-localized tumor at diagnosis had a two-fold risk of suicide and the rate was higher among patients undergoing no treatment, or treatment with chemotherapy or hormones only. It was estimated that 23% of all suicides among male cancer patients and 46% among female cancer patients was associated with the patients having cancer.     

Exposure to asbestos and lung and pleural cancer mortality among pulp and paper industry workers

We studied the mortality from lung and pleural cancers in a cohort of 62,937 male workers employed for at least 1 year in the pulp and paper industry in 13 countries during 1945 to 1996. Mill departments were classified according to probability and level of exposure to asbestos on the basis of available dust measurements and mill-specific information on exposure circumstances. Thirty-six percent of workers were classified as ever exposed to asbestos. Standardized mortality ratios of lung cancer were 0.99 (95% confidence interval [CI], 0.90 to 1.08) among unexposed and 1.00 (95% CI, 0.90 to 1.11) among ever exposed workers. The number of pleural cancer deaths among unexposed workers was 10; that among exposed workers was 14, most of which occurred among maintenance workers. In internal analyses, a trend in mortality from either neoplasm was suggested for estimated cumulative exposure to asbestos, weighted for the individual probability of exposure within the department and for duration of exposure (relative risk for lung cancer for 0.78+ f/cc-years, as compared with < or = 0.01 f/cc-years: 1.44; 95% CI, 0.85 to 2.45; corresponding relative risk for pleural cancer: 2.43; 95% CI, 0.43 to 13.63). Despite a possible nondifferential misclassification of exposure and outcome, this study suggests that the carcinogenic effect of asbestos can be detected among workers employed in industries such as the pulp and paper industry, in which it is not considered to be a major hazard.     

Incidence of cancer among workers producing calcium carbide.

The overall mortality and the incidence of cancer have been studied among male employees at a plant producing calcium carbide. The cohort was defined as all men employed at the plant for at least 18 months in the period 1953 to 1970 and was classified according to 10 occupational categories. The 790 men have been observed from 1953 to 1983 and the incidence of cancer in the cohort has been compared with national incidence rates. A significant excess of colonic cancer (standardised incidence ratio, SIR = 2.09) and of prostatic cancer (SIR = 1.78) was found, and also a slight excess of lung cancer among furnace and maintenance workers (SIR = 1.56). The possible exposure of the workers to polycyclic aromatic hydrocarbons, asbestos, and cadmium is discussed.     

Determinants of lung cancer risk among cadmium-exposed workers.

Workers at a cadmium recovery plant in Globe, Colorado, showed an increased risk of lung cancer, which some investigators have attributed to cadmium exposure. We conducted a cohort mortality analysis of this work force and a case-control analysis of the lung cancer cases within this work force in order to assess the probable causes of the lung cancer excess. The Globe plant began as a lead smelter about 1886, switched to arsenic production in 1920, and became a cadmium metal production facility in 1926. Cadmium, arsenic, and cigarette smoking are three potential lung carcinogens found in this workplace. Industrial hygiene data collected from 1943 onward served as the basis for the National Institute for Occupational Safety and Health (NIOSH)-derived exposure algorithm that assigned cadmium exposure estimates to employees based on their work area in the plant and calendar time. Few exposure data existed for substances other than cadmium. Feedstock ore concentrations were used as a surrogate measure of air arsenic levels. The arsenic content of the fines used as feedstock prior to 1940 was considerably higher than that of the fines used after 1940. Smoking histories had been obtained previously for 45% of the workers. A case-control analysis of the 25 cases of lung cancer known to have occurred among these workers through 1982 was conducted using three controls per case, matched by closest data of hire and age at hire. Potential causal agents for lung cancer included cadmium exposure, cigarette smoking, and arsenic exposure. Exposure variables for each case and control included estimated cumulative cadmium exposure in milligram-years per cubic meter, cigarette smoking history, and plant arsenic exposure status at the time of hire. Estimated cumulative cadmium exposures of cases and controls did not differ overall or within the date-of-hire strata. Cases were more than eight times more likely to have been cigarette smokers than were controls. Lung cancer risk in this workplace was more closely related to the period of hire, not to the cumulative cadmium exposure. The period of hire appears to be a surrogate for arsenic exposure as related to feedstock. The measures used here seem to indicate that exposure to arsenic and cigarette particulates, rather than to cadmium particulates, may have caused the increased rate of lung cancer of these workers.     

Pulmonary function among pulp and paper workers in Berlin, New Hampshire.

Pulmonary function was studied among pulp and paper workers from a production facility in New Hampshire. Subjects were first tested in the 1960s and then surveyed at regular intervals up to 1985. The current study examined results for the 339 subjects who participated in at least one of the two most recent follow up surveys in 1979 and 1985. For the 171 subjects who were tested in both surveys, the pulmonary function values were higher and the effect of pulp mill work was diminished compared with the findings for the 168 subjects who were tested in just one of the two surveys. To avoid the loss of less healthy subjects and the subsequent bias in effect estimate, the 1985 data were analysed cross sectionally with the inclusion of data from 1979 for those subjects who had not been followed up in the last survey. The subjects with work experience in the pulp mill had mean levels of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) lower than those of unexposed subjects who had never worked in the pulp or paper production areas. Based on parameter estimates from regression analysis, each year of employment in the pulp operation was associated with a -5.8 ml change in FEV1 (p = 0.08) and a -7.2 ml change in FVC (p = 0.04). Ninety one per cent of the subjects with pulp mill experience had terminated employment in that area of the company, so the association with decreased lung function appears to be a non-reversible effect that persisted after the cessation of exposure.     

Gastrointestinal cancer among cement workers

Summary A matched case-referent study was conducted to investigate the risk of gastrointestinal cancer in cement workers. All male cases of cancer in esophagus, stomach, colon and rectum in the period 1922–1988 from two parishes surrounding a cement plant were identified. For each case, four referents were chosen, matched to age and year of death. Employment in the cement plant was confirmed as from plant records or job title noted in the parish books. Of 25 cases with a definite colorectal tumour, 40% had been blue-collar cement workers for 25 years or more, compared with 20% of their referents [odds ratio (OR) 3.2; 95% confidence limits (CI) 1.1–9.4]. There were indications of a dose (time of employment)-response relationship. For 18 cases with an esophageal or stomach tumour, the OR for those ever employed as cement workers was 3.2 (CI 1.0–11), but short-term employment predominated, thus making a causal relationship less likely.     

Risk management among benzene-exposed oil refinery workers

Ten benzene-exposed oil refinery workers were genotoxicologically monitored in an annual follow-up study between 1990 and 2003 and compared with 87 industrial and 26 matched controls. Each of the exposed subjects suffered from several intercurrent non-infectious diseases such as joint, rheumatic, gastric and dental problems, as well as kidney and liver dysfunctions. The structural chromosome aberration (CA) yields of the exposed donors suggested a dose-dependent response to the mean peak benzene concentrations in the ambient air. Sister chromatid exchange (SCE), high-frequency SCE, DNA repair, and cell proliferation data also indicated the presence of genotoxic exposure at the workplace. The results of the biological and genotoxicological monitoring indicated the need of intervention (primary prevention of occupational exposure-related chronic non-infectious diseases) including the introduction of zero tolerance of benzene emission, health control, and education with motivation to change life-styles. The decrease in CA frequencies considered as the most established genotoxicological effect markers indicated the positive changes due to the achieved zero tolerance at the workplaces. The results also demonstrated the effectiveness of a trilateral co-operation between the health services, the employer and the employee in order to reduce the risk of the exposure-related intercurrent non-infectious diseases and to prevent further deterioration of the health state of the workers.     

Silicosis and lung cancer among Chinese granite workers.

Of the 184 cases of silicosis registered between 1 January 1970 and 31 December 1984 in Singapore, all the relevant information was available for 159, which were linked to the population-based National Cancer Register for lung cancer. Nine cases of lung cancer were found. The standardized incidence ratio (SIR) was computed with the age- and calendar-specific incidence of lung cancer rates of Chinese males in Singapore as a basis. Excess risk of lung cancer was found (SIR 2.01, 95% confidence interval 0.92-3.81). Adjustment for smoking showed that it alone could not account for the excess lung cancer risk. There was an increasing, but not significant, trend with increasing severity of silicosis and exposure duration. The results suggest that the severity of silicosis and possibly exposure to free silica may have contributed to the excess of lung cancer among the cases of silicosis studied.