Lung cancer and mesothelioma in the pleura and peritoneum among Swedish insulation workers

OBJECTIVES: To estimate the risk of cancer and death in Swedish insulation workers some years after their exposure to asbestos had stopped. One hypothesis was that the risk of lung cancer would tend to decrease some years after the exposure had ended. METHODS: In a cohort study the cancer morbidity and cause of death was investigated in 248 insulation workers and compared with the corresponding morbidity and mortality in the general population. Due to stringent regulations, exposure to asbestos of all types had almost ended in Sweden in the mid- 1970s. Through a questionnaire, surviving insulation workers were asked about their exposure to asbestos and their smoking habits. RESULTS: Between 1970 and 1994 there were 86 deaths compared with the 46.0 expected (standardised incidence ratio (SIR) 1.9; 95% confidence interval (95% CI) 1.5 to 2.3), the increase was mainly due to an increased cancer mortality. The morbidity was increased for lung cancer (11 cases v 2.5 expected (SIR 4.4; 95% CI 2.2 to 7.9)), peritoneal mesothelioma (seven cases; no expected incidence could be calculated as the occurrence is too rare in the general population), cancer in pancreas (five cases v 0.7 expected (SIR 7.1; 95% CI 2.3 to 16.7)). No cases of pleural mesothelioma were found. The risk of lung cancer did not tend to approach that of the general population after the exposure to asbestos decreased. CONCLUSIONS: In the 1980s and the early 1990s, Swedish insulation workers still have a highly increased risk of diseases related to asbestos. The attributable risk for death and cancer was about 50%. The study also confirms the previous finding that mesothelioma in insulation workers seems to be situated in the peritoneum more often than in the pleura.     

A proportional study of cancer registrations of dockyard workers.

Evidence of an occupational effect due to asbestos exposure was sought by comparing cancer registrations for dockyard workers with those for Plymouth men in the same age groups for 1960-69. The results show a significant excess of pleural tumours in the dockyard group but no significant excesses at other sites. Registrations for pleural mesothelioma were recorded for men with many dockyard occupations and the observed mean interval between first exposure to asbestos and registration for a pleural tumour (37.6 years) indicates that cases of pleural mesothelioma may be expected to occur among these workers for many years, even though crocidolite is no longer used in naval ships. A trend of increasing annual excess of stomach and gastrointestinal registrations was observed in the dockyard group. No cases of peritoneal mesothelioma were recorded but it is likely that some did occur which were diagnosed as cancers arising from other sites. This may account for some of the excess of gastrointestinal registrations.     

Bladder tumours in rubber workers: a factory study 1946-1995

BACKGROUND: Prior to December 1949, some British rubber industry workers were inadvertently exposed to the human bladder carcinogen beta-naphthylamine, which was present as a contaminant (at 0.25%) in antioxidants used in manufacturing. This study follows a composite cohort of 6450 men employed at a large tyre factory either during the 'at-risk' period or just after it. METHODS: A group of 2090 at-risk men (employed 1945-1949) and 3038 men, first employed only after January 1950, when the carcinogen had been removed, were followed for their bladder cancer morbidity and mortality experiences. RESULTS: Fifty-eight tumours were registered for those at risk, whereas only 33.9 were expected at national standardized registration rates [SRRN = 171 and 95% confidence interval (CI) = 130-221]. Thirty-nine bladder tumours were reported for the post-1950 intake, whereas 38.3 were expected (SRRN = 102 and 95% CI = 72-139). The use of mortality data did not reveal any underlying hazard because 12 of the 58 at-risk workers with tumours were still alive at the study end date. In only 16 instances was bladder cancer actually certified as the underlying cause of death. Plotting cases by their location of work on a factory plan assisted the interpretation. CONCLUSIONS: A statistically significant elevated risk of bladder cancer for the exposed workforce was evident, but this reversed when the carcinogen was removed from processing in October 1949. The use of morbidity (incidence) data in long-term studies of occupational bladder cancer should be the required methodology if the hazard and risk are not to be underestimated.     

Evaluation of potential reduction in blood and body fluid exposures by use of alternative instruments

BACKGROUND: Injuries from needlestick, sharps injuries and splashes lead to exposure to blood and body fluids with the potential for transmission of blood-borne viruses. AIMS: To identify alternative instruments, which if used would improve worker safety. METHODS: Retrospective review of 161 injuries with identification of safer alternative products for instruments that caused injury. The proportion of injuries that could be prevented was calculated [with 95% confidence intervals (CI)]. RESULTS: The average rate of injury was 7.8/1000 employees per annum (95% CI, 6.8-9.4/1000). In the 2 years the highest rates of injury occurred in pre-registration house officers (164/1000; 95% CI, 64-264/1000), phlebotomists (154/1000; 95% CI, 15-291/1000) and senior house officers (45/1000; 95% CI, 13-77/1000). An upper estimate of 65% (95% CI, 58-72%) of incidents would have been preventable with a change to alternative devices. CONCLUSIONS: Change to the use of intrinsically safer instrumentation has the potential to prevent injury to healthcare workers.     

A proportional study of cancer registrations of dockyard workers.

Evidence of an occupational effect due to asbestos exposure was sought by comparing cancer registrations for dockyard workers with those for Plymouth men in the same age groups for 1960-69. The results show a significant excess of pleural tumours in the dockyard group but no significant excesses at other sites. Registrations for pleural mesothelioma were recorded for men with many dockyard occupations and the observed mean interval between first exposure to asbestos and registration for a pleural tumour (37.6 years) indicates that cases of pleural mesothelioma may be expected to occur among these workers for many years, even though crocidolite is no longer used in naval ships. A trend of increasing annual excess of stomach and gastrointestinal registrations was observed in the dockyard group. No cases of peritoneal mesothelioma were recorded but it is likely that some did occur which were diagnosed as cancers arising from other sites. This may account for some of the excess of gastrointestinal registrations.     

Upper aerodigestive tract cancers in former employees at an iron and steel works

Local concern about numbers of laryngeal cancer cases led to an investigation of the incidence of upper aerodigestive tract (UAT) cancer in an industrial cohort. Males (n = 11 470) who had been directly employed at an iron and steel works in northern England at any time between January 1960 and site closure in September 1983 were followed up for UAT cancers until December 1998. The incidence of UAT and laryngeal cancer was compared to the general population of the region via indirect standardization. Fifty-two members of the cohort developed a UAT cancer during 1960-1998. There were no more UAT cancers than expected [standardized incidence ratio = 97, 95% confidence interval (CI) = 72-127], but slightly more laryngeal cancers than expected (standardized incidence ratio = 118, 95% CI = 78-171), although this estimate was less precise. The lack of complete work histories meant that relationships between cancer incidence and length of service or job categories could not be explored.     

Mortality and cancer incidence in Ontario glass fiber workers

BACKGROUND: In a previous cohort study of glass fiber manufacturing, we found a significant increase in lung cancer. This study extends the follow-up period. METHODS: We conducted a historical prospective study of 2557 men employed in producing glass wool. We obtained work histories, causes and dates of death, and date and site of cancer diagnoses. We computed standardized mortality and incidence ratios (SMR, SIR). RESULTS: The overall SMR for lung cancer was 163 (95% CI = 118-221). The SMR did not vary consistently by duration of employment and time since first employment. However, plant workers with >20 years' employment and >40 years since first exposure had an SMR for lung cancer of 282 (95% CI = 113-582). The SMR dropped with later date of first exposure, but the trend was non-significant. There was an unexpected overall increase in kidney cancer incidence. DISCUSSION: The increase in lung cancer is greater than in other cohorts of glass fiber workers. Since exposure data are lacking from the early years of the plant, we cannot state if the excess was due to glass fibers, other work exposures or other reasons.     

SWORD '99: surveillance of work-related and occupational respiratory disease in the UK

Systematic reports from chest and occupational physicians under the SWORD and OPRA (Occupational Physicians Reporting Activity) surveillance schemes continue to provide a picture of the incidence of occupational respiratory disease in the UK. An estimated total of 4393 incident cases (comprising 4530 diagnoses) were reported during the 1999 calendar year, an increase of 1427 cases over the previous year. Benign pleural disease was the single most frequently reported condition (28% of all diagnoses reported). Occupational asthma cases (1168; 26%) remained high, as did mesothelioma (1032; 23%). Analysis of trends over the past 8 years shows an increase in mesothelioma cases, but little change in asthma. The annual incidence per 100,000 employed people, 1996-1999, for mesothelioma, lung cancer and pneumoconiosis was high amongst construction workers (28.7), miners and quarrymen (26.5), woodworkers (18.9) and gas, coal and chemical workers (15.2). Trends in mesothelioma incidence by birth cohort continue to show an increase in construction workers and a continuing decline in shipyard and insulation workers. The relative proportion of pneumoconiosis cases attributed to coal mining has fallen steadily in workers born since approximately 1920 and most cases are now in men who have been employed in quarrying and rock drilling.     

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.     

Ill-health retirement among healthcare workers in the Southern Health Board of the Republic of Ireland

AIM: To determine the incidence rates, trends and medical causes of ill-health retirement (IHR) among different occupational classes in the Southern Health Board (SHB). METHODS: The 14 702 permanent employees of the SHB were divided into six occupational classes based on socio-economic status and occupational demands. The occupational classes were compared for incidence rates of IHR, age at IHR, years of service and medical causes of IHR. The total group of employees was used as the standard for statistical comparison. Incidence rates were compared using standardized IHR ratios (SIHRRs). Medical causes were compared using proportional ill-health retirement ratios (PIHRRs). RESULTS: Three hundred and three employees were granted IHR from 1994 to 2000.The overall incidence rate of IHR was 2.9 per 1000 employees per annum. The highest SIHRRs occurred in male maintenance staff at 345 (CI: 221-513) and female support staff at 158 (CI: 123-201). With regard to age and years of service, IHR peaked at a time that coincided with enhancement to pension entitlements. The common causes of IHR were musculoskeletal disorder (38%), mental illness(17%), circulatory disorder (12%) and neoplasia (8%). PIHRRs did not vary significantly between the classes. CONCLUSION: IHR was more common among manual healthcare workers. The structure of the pension scheme appeared to influence the timing of IHR. Occupational class did not appear to influence the medical causes of IHR.     

Mortality in a cohort of sugar refinery workers in Arezzo Province, Italy

BACKGROUND AND OBJECTIVES: The aim of this study was to investigate mortality of a cohort of 1,767 male workers employed in a sugar refinery plant located in the Province of Arezzo, Italy, where asbestos had been used from the 1960's for the insulation of thermohydraulic systems and for furnaces. In 1987-88 workers removed the asbestos-cement insulation from the plant. METHODS: The cohort was composed by male workers who were employed in the plant between 1 March 1962 and 1 February 1996, and had worked for at least 2 months. Follow-up started on 1 March 1962, and ended on 31 May, 2003. The population mortality for Tuscany Region was used as the reference. The relative risk was estimated by Standardized Mortality Ratio (SMR) and the confidence intervals were calculated at a 95% level (95% CI). RESULTS: The majority of workers were employed during the summer only. Significant decreases in mortality were observed for overall mortality (SMR = 78; 95% CI = 69-88), all cancers (SMR = 80; 95% CI = 65-97), cardiovascular diseases (SMR = 64; 95% CI = 50-81), lung cancer (SMR = 66; 95% CI = 43-98), and gastrointestinal diseases (SMR = 53; 95% CI = 26-98). Non-significant increases were observed for kidney cancer (SMR = 229; 95% CI = 92-472), and diseases of the nervous system (SMR = 155; 95% CI = 71-294). Kidney cancer mortality for workers employed for > = 5 years was significantly higher (SMR = 508; 95% CI = 105-1485). CONCLUSIONS: Mortality for asbestos-related diseases did not show any increase. The higher kidney cancer mortality for workers employed for > = 5 years could be due to exposures to various carcinogens, that occurred not only in the sugar refinery plant, given that the workers were seasonal and did other jobs during the rest of the year. Asbestos-related deaths could occur in the future among some workers who in 1987-88 were employed on the removal of asbestos-cement insulation from the plant.     

Mortality among workers in an Italian cigarette factory

A cohort study was conducted to evaluate the mortality pattern among female and male workers in a cigarette factory. The study followed 972 female workers and 761 male workers with at least 6 months of cumulative employment from 1 January 1962 through 1 July 1996. Among women, mortality from all causes of death [standardized mortality ratio (SMR) = 0.9; 95% confidence interval (CI) = 0.8-1.1] and mortality from all malignant neoplasms (SMR = 1.1; CI = 0.9-1.3) were consistent with reference rates. Male workers had a significantly reduced overall mortality (SMR = 0.8; CI = 0.7-0.9), while mortality from all malignant neoplasms was as expected (SMR = 0.9; CI = 0.7-1.0). Among female workers the frequencies of deaths from diseases of nervous system (SMR = 2.0; CI = 1.1-3.4) and from non-Hodgkin's lymphoma (NHL) (SMR = 2.7; CI = 1.0-5.6) were elevated at a statistically significant level. No association between duration of employment and diseases of nervous system was observed. A higher risk for NHL, based on three deaths, was reported among female workers with 15 or more years of employment (SMR = 8.1; CI = 2.2-21.0). Although based on small numbers, the excess of NHL here reported suggests that potential exposure to foliar residues of pesticides should be thoroughly considered in tobacco manufacturing.     

Chronic fatigue among bank workers in Brazil

The present study examines the prevalence of chronic fatigue (CF) among bank workers in Brazil and possible associations with gender and working conditions. The study sample included all 735 workers from the department of data processing of a state bank. CF was assessed using the Chalder Fatigue Scale. Working conditions and socio-demographic, socio-economic and psychosocial factors at work were analysed. Psychiatric symptoms were measured with the SRQ-20. The overall estimate of the prevalence of CF was 8.7% [95% confidence intervals (95% CI) = 6.4-10.9%]: 7.8% (95% CI = 5.5-10.7%) among men and 11.0% (95% CI = 6.7-16.9%) among women. The male-female difference was not statistically significant, even after adjusting for minor psychiatric disorders. The overall prevalence of CF without minor psychiatric disorders was 4.5% (95% CI = 2.7-6.3%): 3.9% (95% CI = 1.9-5.9%) among men and 6.4% (95% CI = 2.0-10.1%) among women. In the final model, risk factors for CF were fast work speed [odds ratio (OR) = 3.5], dissatisfaction at work (OR = 3.1), minor psychiatric disorders (OR = 6.8), and medium (OR = 1.8) and heavy domestic workload (OR = 12.0). CF is common among these bank workers and is associated with psychosocial factors at work. Particularly among women, domestic workload, marital status and the presence of young children were associated with CF in the stratified analysis. Domestic workload may add physical and mental stress, putting employees at risk for CF from overload, or CF may cause workers to perceive domestic work as heavy.     

Simian virus 40 and mesothelioma in Great Britain

BACKGROUND: Simian virus 40 (SV40) is a DNA virus that has been shown capable of infecting and transforming cells in various species. Laboratory studies have suggested that inoculation with SV40 is associated with various types of cancer, including mesothelioma. AIMS: To test the hypothesis, via an ecological analysis, that exposure to SV40 via contaminated polio vaccines is a risk factor for mesothelioma in humans. METHODS: Mesothelioma mortality rates in Great Britain for two birth cohorts likely to have been exposed to SV40 via poliovirus vaccination were compared with a birth cohort likely to be largely unexposed. RESULTS: There was some evidence for both males (P < 0.05) and females (P < 0.05) that the mesothelioma mortality rates were higher in the first exposed cohort: rate ratio (RR) = 2.4 [95% CI (confidence interval) 1.2-5.0] and RR = 3.7 (95% CI 1.0-14). However, in the second exposed cohort, mortality rates were elevated in females only, and the evidence was slightly less convincing (P = 0.055). CONCLUSION: Although the results for females show a reduction in the mesothelioma mortality rate coinciding with the introduction of the SV40-free Sabin polio vaccine, the absence of a similar result in males and of a priori biological evidence of a sex-specific SV40 effect, makes chance the most plausible interpretation of these findings.     

Cancer incidence and cancer mortality in a cohort of UK semiconductor workers, 1970-2002

OBJECTIVE: To examine cancer risks in a cohort of workers employed in the manufacture of semiconductors. METHODS: The mortality (1970-2002) and cancer morbidity (1971-2001) experienced by a cohort of 1807 male and female workforce employees from a semiconductor factory in the West Midlands (UK) have been investigated. Standardized mortality ratios (SMRs) and standardized registration ratios (SRRs) were used to assess mortality and morbidity, respectively. RESULTS: Overall mortality was close to expectation in males [SMR 99, 95% (confidence interval) CI 79-122] and significantly below expectation in females (SMR 74, 95% CI 65-85). Incidence of all sites of cancer was somewhat elevated in males (SRR 130, 95% CI 95-173) but close to expectation in females (SRR 94, 95% CI 82-109). There were significant deficits of deaths from cancer of the oesophagus in males and females combined and from cancer of the breast in females. Significantly elevated SRRs were found in males for cancer of the rectum [Observed (Obs) 6, SRR 284, 95% CI 104-619], in females for cancer of the pancreas (Obs 10, SRR 226, 95% CI 108-415) and malignant melanoma (Obs 11, SRR 221, 95% CI 110-396) and in males and females combined for cancer of the rectum (Obs 19, SRR 199, 95% CI 120-310) and malignant melanoma (Obs 12, SRR 217, 95% CI 112-379). Detailed work history data were unavailable for analysis. The finding of excess morbidity was not mirrored in the corresponding mortality findings. CONCLUSIONS: The study found elevated morbidity for a number of cancer sites that may be unconnected with occupation. Elimination of all possible occupational causes will, however, require more detailed analyses of cancer risks in relation to exposure histories.     

Cancer incidence among asbestos-exposed chemical industry workers: an extended observation period

A previous study on the incidence of cancer in a cohort of 286 asbestos-exposed electrochemical industry workers observed from 1953 through 1980 has been extended with another 8 years of follow-up. The incidence of cancer was derived from the Cancer Registry of Norway, and the expected figures were calculated by a life table method. During the extended follow-up period from 1981 through 1988, among the cohort members there were 12 new cancer cases versus 14.2 expected (SIR 85, 95% CI 44-158). In a lightly exposed sub-cohort, the extended follow-up revealed 4 cases of lung cancer or pleural mesothelioma (ICD, 7th revision 162-163) versus 1.6 cases expected (SIR 256, 95% CI71-654). In a heavily exposed sub-cohort, the corresponding figures were 3 and 0.5 (SIR 588, 95% CI 118-1,725).     

Factors influencing uptake of influenza vaccination among hospital-based health care workers

BACKGROUND: Vaccination of health care workers against influenza has been shown to lower mortality among elderly patients, but uptake of voluntary vaccination among health care workers remains low. AIMS: Factors influencing uptake of vaccination were examined among a cross-section of health care workers based in an NHS Trust. METHODS: A structured, self-administered questionnaire was mailed to a random sample of health care workers based in the acute services sector of a UK National Health Service Trust, 6 months following a voluntary immunization programme implemented as part of the Scottish Executive Health Department winter planning arrangements for 2000-2001. The programme was promoted using posters in clinical areas and a single leaflet given to all staff through a paycheck advice note. RESULTS: Five hundred and fifty-one health care workers (53%) responded to the questionnaire and influenza vaccination was accepted by 150 (28%). The occupational health poster strongly influenced the decision to accept vaccination [odds ratio (OR) = 11.01; 95% confidence interval (CI) = 2.13-56.80; P < 0.0001]. Other significant influences included female sex (OR = 9.11; 95% CI = 1.26-65.72) and perceived risk of contracting flu without the vaccine (OR = 7.70; 95% CI = 1.44-41.05). Misconceptions regarding the purpose of the vaccination campaign were common and concern regarding possible side-effects was a deterring factor for vaccination uptake. CONCLUSION: Our study showed that visual material displayed throughout the workplace strongly influenced the acceptance of influenza vaccination. Future campaigns should also emphasize the positive benefits to patients of health care worker immunization, with readily accessible information regarding side-effects available from all sources.     

Effects of overtime work on blood pressure and body mass index in Japanese male workers

BACKGROUND: Effects of overtime work on health is a controversial issue. AIMS: To determine the effects of overtime work on blood pressure and body mass index (BMI) for male workers in Japan. METHODS: Participants were 323 male participants of three companies. Data were collected by occupational physicians at periodic physical examinations and additional examinations. The time courses for the development of definite hypertension and an increase in BMI were recorded. The Kaplan-Meier method was used to estimate the cumulative incidence rates of developing definite hypertension and increasing BMI, and the Cox proportional hazard model was used to determine the adjusted relative hazard of overtime work. RESULTS: The age-adjusted incidence rates of developing definite hypertension and increasing BMI were significantly lower among the participants whose mean overtime was > or =50 h than among those whose mean overtime was <50 h/month (log-rank P < 0.05). The Cox proportional hazard model indicated that those who worked a mean overtime of > or =50 h/month had lower risks of developing definite hypertension (hazard ratio, 0.36; 95% CI, 0.15-0.88; P < 0.05) and increasing their BMI (hazard ratio, 0.44; 95% CI, 0.31-0.63; P < 0.01) after adjusting for age. CONCLUSIONS: The results of this study indicate that workers whose mean overtime was > or =50 h have lower risks of developing definite hypertension and increasing their BMI.     

Mortality in employees of a railway rolling stock factory

A study was carried out on the mortality of 3741 individuals who worked in a factory making railway rolling stock, in which crocidolite was used to insulate the coaches in the 60's and 70's. Employees who had worked in the factory between 1960 and 1995 were included in the study, with the main aim of investigating cancer mortality in these subjects. 9 cases of mesothelioma were known in this factory before starting the study. The follow-up was performed from 1960 to 1996. The SMR's for lung cancer and mesothelioma in 2737 blue-collar workers were 1.23 (CI 95% = 1.00-1.50) and 6.50 (CI 95% = 2.96-12.38) respectively, based on national rates. The excesses were mainly found among subjects who had worked before 1970 with duration of employment exceeding 20 years.     

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.