Cancer mortality among chemical workers in an Italian plant

Objective of this study was to assess the mortality experience of a cohort of chemical workers at a plant located in central Italy. Subjects employed for any time between 1954 and 1970 at the chemical plant were included in the cohort and followed up to June 1991. The workers were classified as having ever/never worked in one of the following work processes: organic chemicals, acid mixtures, cleansing agents and insecticides. Mortality experience of the cohort was compared with that of the regional population by computing SMRs (standardized mortality ratios) and 90% CI (confidence intervals). Vital status was ascertained for 96% of the 505 cohort members. All causes of mortality for the entire cohort were lower than expected (Obs: 176; SMR: 0.90; 90% CI: 0.79–1.03). Analysis by work process revealed an increased mortality for lymphatic and hematopoietic tissue neoplasm in the cleansing agents department (Obs: 3; SMR: 5.00; 90% CI: 1.36–12.9); peritoneum and retropertioneum neoplasm in the organic compounds production (Obs: 2; SMR: 13.33; 90% CI: 2.37–42.0), and bladder cancer in the insecticides process (Obs: 3; SMR: 3.53; 90% CI: 0.96–9.12). Although the study had a low statistical power, the increased cancer risks detected are consistent with previous observations and may be of etiologic interest.     

Cancer mortality among shoe manufacturing workers: an analysis of two cohorts.

OBJECTIVES: To examine the cancer risk of shoe manufacturing workers and evaluate whether the risk was associated with exposure to leather dust and solvents. METHODS: Data from two historical cohort studies of shoe workers were expanded and analysed in parallel. A total of 4215 shoemakers from England contributing 103 726 person-years at risk and 2008 shoemakers from Florence, Italy, contributing 54,395 person-years at risk were included in the analysis. Exposure to leather dusts and solvents from glues was evaluated on the basis of job title information. Standardised mortality ratios (SMR) were calculated as ratios of observed deaths (Obs) over expected derived from national mortalities. RESULTS: Overall mortality was lower than expected in both cohorts (English cohort: Obs 3314, SMR 81, 95% confidence interval (95% CI) 78-84; Florence cohort: Obs 333, SMR 87, 95% CI 78-97). An increased risk of nasal cancer was found (English cohort: Obs 12, SMR 741; Florence cohort: Obs 1, SMR 909). 10 of the 13 cases occurred among English workers employed in the manufacture of welted boots (SMR 926, 95% CI 444-1703), a sector of the industry thought to have had the highest exposure to leather dust. Mortality from leukaemia was not increased in the English cohort (Obs 16, SMR 89), but was increased in the Florence cohort (Obs 8, SMR 214, 95% CI 92-421); and the highest risk was found among shoe workers in Florence who were first exposed between 1950 and 1959 when exposure to benzene was substantial (Obs 3, SMR 536, 95% CI 111-1566). Some evidence for an excess risk of stomach, bladder, and kidney cancer, as well as multiple myeloma and non-Hodgkin's lymphoma was also found in the Florence cohort only among workers employed in jobs with the highest exposure to solvents. CONCLUSIONS: These findings confirm the associations between exposure to leather dust and nasal cancer and between exposure to benzene and leukaemia in the shoe manufacturing industry and suggest that the risk of other cancers may be increased among workers exposed to solvents or glues.     

A cohort study of art glass workers in the Empoli area

The investigation aimed at studying cause-specific mortality of art glass workers employed in 17 industrial facilities in Tuscany, Italy. A cohort of 3390 workers employed for at least 1 year was obtained from company payrolls. Follow-up was between the year each factory started operations, mostly in the mid-fifties, and the end of 1993. The cause specific expected mortality was computed relative to Tuscany rates, specified for gender, 5-year age groups and calendar year. Separate analyses were carried out for the job titles of makers, batch mixers and grinders. For males, 3180 individuals, the observed mortality for cancer causes was above the expected for the lung [standardized mortality ratio (SMR) 123, 10 observed (Obs)], larynx (SMR 166, 10 Obs), stomach (SMR 105, 30 Obs) and brain (SMR 150, 7 Obs). For non-cancer causes observed mortality was above expected for hypertensive diseases (SMR 178, 10 Obs) and diseases of the genitourinary system (SMR 169, 11 Obs). Increases for the above listed causes were shown also among makers. Mortality for larynx and lung cancer increased with time since first exposure and significantly increased SMRs were observed for 21 or more years since first exposure: this pattern was still present with smoking adjustment. The results showed consistently increased mortality for lung and larynx cancer in the overall cohort and among makers. Stomach cancer, brain cancer, hypertensive diseases and diseases of the genitourinary system were also increased in the overall cohort and among makers.     

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.     

Epidemiologic study of workers exposed to vinyl chloride in Porto Marghera: mortality update

The investigation describes mortality of vinyl chloride exposed workers in the Montedison-Enichem plant located in Porto Marghera, near Venice, Italy. A total of 1658 workers employed from start of production (1950), present in 1956 or successively hired until 1985, were followed up between 01.01.1973 and 31.07.1999, for a total of 41.037 person years at risk: 248 deaths were observed. Mortality from all causes compared with regional population was lower than expected, (SMR 0.75; 90% CI 0.68-0.83) and from all malignant neoplasms similar to expected (SMR 0.94; 90% CI 0.81-1.09). SMR for primary liver cancer was significantly increased (SMR 2.78 90% CI 1.86-4.14). In the first year since leaving employment observed mortality was significantly above the null value for all causes (SMR 2.76; 90% CI 1.94-3.91), all malignant neoplasms (SMR 1.89; 90% CI 0.97-3.92) and cardiovascular diseases (SMR 2.37; 90% CI 1.13-4.95). Mortality rates for liver angiosarcoma (6 cases) increased with latency (trend test x 2 (1df) = 25.20 p < 0.001) and cumulative exposure (trend test x 2 (1df) = 61.00 p < 0.001), there were no cases with duration of employment less than 12 years, latency less than 10 years and for cumulative exposure less than 2.379 ppm-years. Mortality rates for hepatocellular carcinoma (12 cases) and liver cirrhosis (20 cases) showed a similar pattern for cumulative exposure. Observed mortality from lung cancer was higher than expected among those workers whose only job title was bagger. In the analysis accounting for latency, age and calendar period the RR for only bagger was 2.31 (90% CI 1.15-4.61). Mortality pattern for all causes, all malignancies and cardiovascular disease increased by time since employment, as expected in presence of a particularly strong Healthy Worker Effect (HWE). These results and the increased SMR values during the first year since leaving employment indicate that workers were selected into employment on the basis of good health conditions and early selective removal of weaker ones followed. The study results confirm the causal relationship between VCM exposure and liver angiosarcoma, and add supplementary evidence in favour of a causal explanation of the excess risk for hepatocellular carcinoma and liver cirrhosis as well as lung cancer among only baggers.     

Cohort study of art glass workers in Tuscany, Italy: mortality from non-malignant diseases

This investigation studies cause-specific mortality of art glass workers employed in 17 industrial facilities in Tuscany, Italy. A cohort of 3,390 workers employed for at least 1 year was enumerated from company payrolls. Follow-up was between the start of employment in each factory and 31 December 1993. The cause-specific expected mortality was computed relative to Tuscany rates and specified for gender, 5-year age groups and calendar year. Separate analyses were carried out for the jobs of makers and formers and for batch mixers. Among males (3, 180 individuals) observed mortality for non-cancer causes was higher than expected for hypertensive disease [standardized mortality ratio (SMR) = 178, 90% confidence interval (90% CI) = 96-301], pneumoconiosis (SMR = 200, 90% CI = 94-376) and diseases of the genitourinary system (SMR = 169, 90% CI = 95-279). Increases for the above causes were shown also among makers and formers: hypertensive disease (SMR = 182, 90% CI = 85-341), pneumoconiosis (SMR = 250, 90% CI = 109-493) and diseases of the genitourinary system (SMR = 224, 90% CI = 121-380). For batch mixers an increase was present for cerebrovascular disease. The observed mortality for cancer causes was above the expected for cancers of the larynx, lung, stomach and brain. This study points to the existence for Tuscan glass workers of health effects in addition to cancer; previously observed carcinogenic effects were also confirmed.     

Retrospective cohort mortality study of cancer among sewage plant workers

There is little known about the incidence of cancer among sewage workers. In this paper we examine findings from a retrospective cohort study of 487 white male sewer authority workers employed between January 1950 and October 1979. Vital status was ascertained for 93% of the cohort yielding a total of 6,886 person years. Total mortality from all causes was comparable to that of the general white male U.S. population (Standardized Mortality Ratio [SMR] = 0.91, 95% Confidence Interval [CI] = 0.77-1.07). The cohort was subdivided into those not exposed, and sewer workers who were exposed to sewage effluent, sludge, or wastewater containing chemicals including potential carcinogens. Among the nonexposed group, mortality from all causes was significantly low (SMR = 0.55, 95% CI = 0.33-0.88). Among the exposed sewer workers, mortality from all causes was not significantly different from that of the general white male U.S. population (SMR = 1.00, 95% CI = 0.84-1.19). Mortality from all cancers among exposed sewer workers was slightly higher than that of the general population (SMR = 1.19, 95% CI = 0.79-1.7). Statistically significant elevated mortality ratios were seen for cancer of the larynx (SMR = 7.93, 95% CI = 1.59-23.96), and cancer of the liver (SMR = 5.4, 95% CI = 1.10-16.05). Careful study of the medical and occupational histories of these cases suggested that larynx cancer was possibly work-related, while liver cancer was not. A group estimated to be the highest exposed, composed predominantly of operatives, had a higher directly adjusted death rate from all malignant neoplasms combined compared to all other workers (rate ratio = 1.64). These findings of increased risk of cancer among exposed sewage workers, especially operators, are based on small number of cases and should be interpreted with caution. Studies of larger cohorts are needed to clarify the risk of these cancers among sewage workers.     

Mortality and incidence of cancer among a cohort of self employed butchers from Geneva and their wives.

To investigate whether specific cancers are associated with the occupation of butcher, as has been reported from other countries, a historical prospective cohort study was undertaken. The cohort consisted of all self employed butchers (n = 552) and pork butchers (n = 310) born since 1880 who set up a shop in the canton of Geneva from 1901 to 1969, and of their wives (n = 887). The study group was followed up from 1901 to 1990 for general mortality, from 1942 to 1990 for cause specific mortality, and from 1970 to 1989 for incidence of cancer. There was no trace of 45 men (5%) and 52 women (6%). Compared with the general population of the canton of Geneva, butchers and pork butchers experienced a significant increase, taking into account 15 years of latency, in mortality from all causes (observed deaths (Obs) 540, expected deaths (Exp) 445.5, standardised mortality ratio (SMR) 121, 90% confidence interval (90% Cl) 113-130). There were significant excesses in incidence and mortality from colorectal cancer, cancer of the prostate, and all malignant neoplasms, and in incidence of cancer of the liver. The risk of lung cancer was significantly increased among pork butchers (SMR 176, 90% Cl 114-262; standardised incidence ratio (SIR) 231, 90% Cl 137-368) but not among butchers (SMR 92, 90% Cl 59-138; SIR 113, 90% Cl 67-179). There was also a significant increase in mortality from cancer of the larynx among butchers. For non-malignant causes of death significant excesses were found among all men for ischaemic heart disease, motor vehicle accidents, and cirrhosis of the liver. Analysis of subgroups showed a cluster of deaths from leukaemia among older butchers born between 1880 and 1899 (Obs 5, Exp 0.6, p < 0.0001). Exposure of pork butchers to polycyclic aromatic hydrocarbons during meat smoking, which was assessed in a contemporary study, might have contributed to their increased risk of lung cancer. The possible role of other factors, especially cigarette smoking, nitrosamines, and oncogenic viruses was discussed. Moreover, there was evidence from another contemporary study that butchers and pork butchers ate more animal fat, and probably more animal protein, than the average male population of Geneva. These results suggest that dietary factors could be implicated in the excesses of colorectal cancer, cancer of the prostate, and ischaemic heart disease. An increased risk for alcohol abuse might explain the excesses of liver cirrhosis, cancer of the liver, cancer of the larynx and motor vehicle accidents. Among all wives overall mortality was similar to that expected (SMR 100, 90% Cl 93-108) and there was no significant excess risk for any specific cancer nor for any non-malignant cause of death. Results for cancer of the cervix uteri, especially among subgroups, suggest an increased risk consistent with previous findings from other countries.     

Cancer mortality in a cohort of male German iron foundry workers

BACKGROUND: Observations of an increased incidence of cancers of the upper aero-digestive tract (pharynx, esophagus, larynx, lung) among workers of local German foundries gave rise to concern about a potentially elevated occupational risk of those cancer sites. The purpose of the study was to examine whether occupational exposure in iron foundries increases the risk of cancer. METHODS: A historical cohort study of 17,708 male German production workers in 37 iron foundries who were first employed in 1950-1985 with a minimum employment period of 1 year was initiated. Employment and occupational histories were collected. Mortality was compared with that of the German general population during 1950-1993 using a new method for computing the SMR when not all causes of death are available (called SMR*). RESULTS: Mortality from all causes was elevated to SMR = 115.4 (95% confidence interval (CI) = 111.9-119.1), as was for total cancer (SMR* = 123.8, CI = 102.1-152.6), especially cancers of the lung (SMR* = 163.9, CI = 123.9-223.0) and liver (SMR* = 322.5, CI = 149.5-844.8), and diseases of the respiratory system (SMR* = 147.6, CI = 100.4-221.5). Non-significant elevations of mortality were also found for cancers of the mouth and pharynx (SMR* = 153.5, CI = 82.3-359.8) and larynx (SMR* = 173.1, CI = 85.5-550.5). Mortality from various causes of death was higher among workers with shorter exposure periods than among long-term employees. The elevated mortality persisted for years and decades after termination of employment. CONCLUSIONS: The results provide further evidence for an increased risk of lung cancer and possibly other cancers of the upper aero-digestive tract among foundry workers. Special attention should be paid to the strongly increased mortality from liver cancer and the mortality pattern among employees having terminated work.     

Mortality of UK oil refinery and petroleum distribution workers, 1951-2003

BACKGROUND: The health of UK petroleum industry workers has been monitored for many years. AIM: To identify any long-term adverse health outcomes from occupational exposures in this industry. METHODS: The mortality (1951-2003) and cancer morbidity (1971-2003) experienced by cohorts of 28,555 oil refinery workers and 16,477 petroleum distribution workers has been investigated. Study subjects were all those males first employed in the period 1946-74 at one of eight UK oil refineries or 476 UK petroleum distribution centres; all subjects had a minimum of 12 months employment with some employment after 1 January 1951. Observed numbers of cause-specific deaths and site-specific cancer registrations were compared with expectations based on national mortality and cancer incidence rates. RESULTS: Standardized mortality ratios (SMRs) were significantly <100 for all causes both in oil refinery workers (Obs 11,156, SMR 89) and in petroleum distribution workers (Obs 7320, SMR 96). Significantly elevated SMRs were shown in oil refinery workers for cancer of the pleura (mesothelioma) (Obs 64, SMR 261) and melanoma (Obs 48, SMR 168). Significantly elevated SMRs were not found in petroleum distribution workers for any site of cancer. Significantly elevated standardized registration ratios (SRRs) were only shown in oil refinery workers and for cancer of the pleura (mesothelioma) (Obs 115, SMR 274), melanoma (Obs 85, SMR 129) and other skin cancer (Obs 983, SRR 117). CONCLUSIONS: The only findings that showed clear evidence of an occupational cancer hazard were those for mesothelioma in oil refinery workers.     

Mortality of workers at a nickel carbonyl refinery, 1958-2000

Background: Excess risks of respiratory cancer have been shown in some groups of nickel exposed workers. It is clear, however, that not all forms of nickel exposure are implicated in these excess risks.

Aim: To determine whether occupational exposures received in a modern nickel carbonyl refinery lead to increased risks of cancer, in particular nasal cancer and lung cancer.

Methods: The mortality experienced by a cohort of 812 workers employed at a nickel refinery was investigated. Study subjects were all male workforce employees first employed in the period 1953–92 who had at least five years' employment with the company. Observed numbers of cause specific deaths were compared with expectations based on national mortality rates; SMRs were also calculated by period from commencing employment, year of commencing employment, and type of work.

Results: Overall, standardised mortality ratios (SMRs) were close to 100 for all causes (Obs 191, SMR 96, 95% CI 83 to 111), all neoplasms (Obs 63, SMR 104, 95% CI 80 to 133), non-malignant diseases of the respiratory system (Obs 18, SMR 97, 95% CI 57 to 153), and diseases of the circulatory system (Obs 85, SMR 94, 95% CI 75 to 116). There were no significantly increased SMRs for any site of cancer. There was a non-significant excess for lung cancer (Obs 28, Exp 20.17, SMR 139, 95% CI 92 to 201), and in subgroup analyses a significantly increased SMR of 231 (Obs 9) was found for those 142 workers with at least five years' employment in the feed handling and nickel extraction departments. In the total cohort there was a single death from nasal cancer (Exp 0.10).

Conclusions: The non-significant excess of lung cancer deaths may well be a chance finding, but in light of previous studies some role for nickel exposures cannot be excluded.

     

Mortality and cancer morbidity of production workers in the United Kingdom flexible polyurethane foam industry.

OBJECTIVE--To describe cause specific mortality and site specific cancer morbidity among workers employed in factories that produce polyurethane foams, and to determine if any part of the experience may be due to occupation, and in particular to exposure to diisocyanates. DESIGN--Historical prospective cohort study. SETTING--11 factories in England and Wales. SUBJECTS--8288 male and female production employees with some employment in the period 1958-79, and with a minimum period of employment of six months. MAIN OUTCOME MEASURES--Observed and expected numbers of deaths for the period 1958-88, and corresponding figures for cancer registrations for the period 1971-86. RESULTS--Compared with the general population of England and Wales, standardised mortality ratios (SMRs) for all causes and all neoplasms were 97 (observed deaths (Obs) 816) and 88 (Obs 221) respectively. Statistically significant excesses were found among women for cancer of the pancreas (expected deaths (Exp) 2.2, Obs 6, SMR 271, 95% CI 100-595) and cancer of the lung (Exp 9.1, Obs 16, SMR 176, 95% CI 100-285). Similar excesses were not found among male employees, and the SMRs for cancers of the lung and pancreas among the total study population were 100 (Obs 81) and 136 (Obs 14) respectively. Overall incidence of cancer was also below expectation (SRR 94, Obs 277), although statistically significant excesses among women were found for cancers of the larynx and kidney, based on three and four cases respectively. Incident cancers of the lung and pancreas among women were also in excess, although these findings were not independent of the findings for mortality. Poison regression did not indicate that ever having been employed in jobs attracting either higher or lower exposure to isocyanates was a risk factor for the mentioned cancers. A nested case-control design was used to investigate any associations with nine other occupational exposures. No statistically significant association was found. CONCLUSIONS--In general, cancer rates in this population were lower than those for the general population. All increased cancer rates among women occurred at sites of cancer known to be related to cigarette smoking, and these excesses are probably due to a combination of cigarette smoking, chance, and factors unrelated to the industry under study.     

Cause of death among workers of a refinery in Rome]

We evaluated mortality among subjects employed in an oil refinery plant in Rome, Italy. We studied two subgroups of refinery employees: blue collar and white collar workers. A total of 682 men (505 blue collars, 148 white collars, 29 unknown) employed between 1965 and 1992, were followed up for mortality since employment in the plant to July 1999. Standardized Mortality Ratios (SMR), and their 90% Confidence Intervals (90% CI), comparing mortality rates of the cohort members with those of the general population of the Lazio region. For blue collar workers, we performed analyses by latency since first employment and by duration of employment for selected cancer sites. We observed 94 total deaths (100.8 expected) (SMR = 0.93; 90% CI = 0.78-1.11) among blue collar workers and 16 total deaths (31.7 expected) (SMR = 0.50; 90% CI = 0.32-0.77) among white collar workers, and a large deficit of deaths from non-neoplastic cardiovascular diseases (respectively SMR = 0.60; 90% CI = 0.41-0.86 and SMR = 0.18; 90% CI = 0.03-0.56). All cancer mortality was slightly increased only in blue collars (SMR = 1.27 CI = 0.97-1.65). There was an excess risk from cancer of the lung (20 obs SMR = 1.80, 90% CI = 1.19-2.62), bladder (5 obs SMR = 3.19, 90% CI = 1.26-6.72), and benign/unspecified cancer of the brain (4 obs SMR = 4.11, 90% CI = 1.12-10.6). The lower mortality from cardiovascular disease indicates the presence of a strong healthy worker effect. The findings of elevated mortality from cancer of the lung and bladder in blue collar workers are in agreement with those of other studies. Confounding factors from cigarette smoking might have played only a marginal role in influencing the results. Exposure to polynuclear aromatic hydrocarbons (PAHs) is a plausible explanation for the excesses found.     

Mortality of UK electricity generation and transmission workers, 1973-2002

OBJECTIVE: To examine mortality from cancer and non-malignant causes among a large cohort of UK electricity generation and transmission workers. METHODS: The mortality experienced by a cohort of 83,923 employees of the former Central Electricity Generating Board of England and Wales was investigated for the period 1973-2002. All employees had worked for at least 6 months with some employment between 1973 and 1982. Standardized mortality ratios (SMRs) were used to assess mortality in the total cohort and in three sub-cohorts: power station workers, substation and transmission workers and workers at non-operational locations. These classifications were based on the place of work of the first known job. RESULTS: Overall mortality was significantly below that expected, based on national rates [males: observed (Obs) 18,773, expected (Exp) 22,497.9, SMR 83; females: Obs 1122, Exp 1424.9, SMR 79]. Statistically significant deficits of deaths were also found for most of the major disease groupings. However, significant excesses of deaths were found in male power station workers for cancer of the pleura (Obs 129, Exp 30.3, SMR 426) and in male workers from non-operational locations for cancer of the brain (Obs 55, Exp 36.0, SMR 153). There was also a non-significant excess of deaths from cancer of the breast in male power station workers (Obs 10, Exp 5.3, SMR 190). CONCLUSIONS: Mortality was exceptionally low for most causes of death but late health effects from earlier asbestos exposure were still in evidence.     

Mortality among a cohort of United Kingdom steel foundry workers with special reference to cancers of the stomach and lung, 1946-90.

OBJECTIVE--The aim was to describe cause specific mortality among steel foundry workers and to determine if any part of the experience may be due to occupation. DESIGN--Historical prospective cohort study. SETTING--Nine steel foundries in England and one in Scotland. SUBJECTS--10,438 male production employees first employed in the period 1946-65 and with a minimum period of employment of one year. MAIN OUTCOME MEASURES--Observed and expected numbers of deaths for the period 1946-90. RESULTS--Compared with the general population of England and Wales, standardised mortality ratios (SMRs) for all causes and all neoplasms were 115 (observed deaths (Obs) 3976) and 119 (Obs 1129) respectively. Statistically significant excesses were found for cancer of the stomach (Obs 124, expected deaths (Exp) 92.5, SMR 134, 95% confidence interval (95% CI) 111-160) and cancer of the lung (Obs 551, Exp 378.3, SMR 146, 95% CI 134-158). A raised SMR (153) was also found for non-malignant diseases of the respiratory system. Classifications of jobs attracting either higher dust or higher fume exposures did not usefully predict these increased SMRs. Poisson regression was used to investigate risks of mortality from all cancers, cancer of the stomach, cancer of the lung, and non-malignant diseases of the respiratory system associated with duration of employment in the foundry area, the fettling shop, the foundry area/fettling shop, and the industry in general. Monotonic dose-response relations were not found, although there were positive trends for lung cancer and employment in the foundry area/fettling shop (1.0, 1.21, 1.44, 1.26) and for diseases of the respiratory system and employment in the fettling shop (1.0, 1.37, 1.18, 1.35). CONCLUSIONS--Confident interpretation of the causes of the raised SMRs was not possible. There was limited evidence of an occupational role in the excesses of lung cancer and diseases of the respiratory system. Smoking history was shown, in an indirect way, to be an unlikely explanation.     

Cancer mortality among workers in the German rubber industry: 1981-91.

OBJECTIVES: To determine the cancer specific mortality of active and retired workers of the German rubber industry with emphasis on cancer sites which have been associated with the rubber industry in previous studies. METHODS: A cohort of 11,663 German men was followed up for mortality from 1 January 1981 to 31 December 1991. Cohort members were active (n = 7536) or retired (n = 4127) at the beginning of the study, and had been employed for at least one year in one of five study plants producing types or general rubber goods. Vital status was ascertained for 99.7% of the cohort members, and cause of death found for 96.8% of the 2719 decedents. Age and calendar year adjusted standardised mortality ratios (SMR) and 95% confidence intervals (95% CI) were calculated overall from national reference rates and stratified by year of hire and by years since hire. RESULTS: Mortalities from all causes (SMR 108; 95% CI 104-112) and all cancers (SMR 111; 95% CI 103-119) were significantly increased in the study cohort. Significant excesses in the mortalities from lung cancer (SMR 130; 95% CI 115-147) and pleural cancer (SMR 401; 95% CI 234-642) were identified. SMRs higher than 100 were found for cancers of the pharynx (SMR 144; 95% CI 76-246), oesophagus (SMR 120; 95% CI 74-183), stomach (SMR 110; 95% CI 86-139), rectum (SMR 123; 95% CI 86-170), larynx (SMR 129; 95% CI 69-221), prostate (SMR 108; 95% CI 84-136), and bladder (SMR 124; 95% CI 86-172), as well as for leukaemia (SMR 148; 95% CI 99-213). Mortalities from liver cancer, brain cancer, and lymphoma were lower than expected. CONCLUSIONS: Mortalities from cancer of several sites previously associated with the rubber industry were also increased among workers of the German rubber industry. Results of the stratified analyses are consistent with a role of occupational exposure in the aetiology of some of these cancers.     

Mortality of mastic asphalt workers

This study was conducted to investigate the adverse health effects of exposure to bitumen fumes. A cohort of 679 mastic asphalt workers was followed from 1959 to 10 June 1986, during this period 169 deaths occurred. The overall standardized mortality ratio (SMR) was 163 (95% confidence interval (95% CI) 141-190), the SMR was 225 (95% CI 172-288) for cancer and 223 (95% CI 130-358) for external causes. Among persons aged 40 to 89 years, significant increases were seen for lung cancer (SMR 290, 95% CI 188-429), nonpulmonary cancer (SMR 200, 95% CI 141-276), and liver cirrhosis (SMR 467, 95% CI 188-962). Bronchitis, emphysema, and asthma also occurred in excess (SMR 207, 95% CI 95-393). In conclusion, the inhalation of bitumen fumes may have contributed to the elevated mortality from cancer and respiratory diseases among mastic asphalt workers.     

Meta-analysis of studies of occupational exposure to vinyl chloride in relation to cancer mortality

OBJECTIVE: A meta-analysis was made of studies addressing occupational exposure to vinyl chloride in relation to cancer mortality. METHODS: Two recently updated multicenter cohort studies and six smaller studies were identified. For selected neoplasms, standardized mortality ratios (SMR) and 95% confidence intervals (95% CI) were abstracted (or calculated from raw data). In cases of lack of heterogeneity (P-value > or = 0.01), meta-analyses were conducted using a random-effects model. RESULTS: With SMR values ranging from 1.63 to 57.1, all six studies for which these ratios could be obtained suggested an increased risk of liver cancer. For four of these studies, excesses persisted when known cases of angiosarcoma of the liver (ASL) were excluded. The meta-SMR for liver cancers other than ASL (based on the 2 large cohorts) was 1.35 (95% CI 1.04-1.77). The meta-SMR for lung cancer was 0.90 (95% CI 0.77-1.00, based on 5 studies), although higher SMR values were reported in early studies. The meta-SMR for brain cancer, based on 5 studies, was 1.26 (95% CI 0.98-1.62). For soft tissue sarcomas, the meta-SMR based on 4 studies was 2.52 (95% CI 1.56-4.07). The meta-SMR for lymphatic and hematopoietic neoplasms in the 2 large studies was 0.90 (95% CI 0.75-1.01), although 3 of the smaller studies reported significant excesses. CONCLUSIONS: Apart from the known risk of ASL, workers exposed to vinyl chloride may experience an increased risk of hepatocellular carcinoma and soft-tissue sarcoma; however, these results may have been influenced by the underdiagnosis of true ASL. Increased mortality from lung and brain cancers and from lymphatic and hematopoietic neoplasms cannot be excluded; mortality from other neoplasms does not appear to be increased.     

A "lugged" analysis of lung cancer risks in UK carbon black production workers, 1951-2004

BACKGROUND: Previously published analyses of excess lung cancer risks in UK carbon black production workers attracted no confident interpretation. METHODS: The mortality of a cohort of 1,147 male manual workers from five UK factories manufacturing carbon black was investigated for the period 1951-2004. All subjects were first employed in the period 1947-74 and were employed for 12 months or more. Limited work histories were available to calculate estimates of individual cumulative exposure to carbon black. RESULTS: Based on serial rates for the general population of England and Wales, significantly elevated mortality was observed for lung cancer (Obs 67, SMR 146, P < 0.01) but not for all other causes combined (Obs 426, SMR 106). There was highly elevated lung cancer mortality at two of the plants (SMR 230, Obs 35) but no excess mortality at the other three plants combined (SMR 104, Obs 32). Analyses by period since leaving employment indicated elevated lung cancer risks were limited to those workers with some employment in the most recent 15 years. SMR analyses found an overall positive significant trend between lung cancer risks and cumulative carbon black exposure received in the most recent 15 years. Poisson regression analyses provided different results depending on which variables were adjusted for. CONCLUSIONS: The findings suggest that carbon black, or chemicals associated with the production of carbon black, had an effect on later stages of lung cancer carcinogenesis at two of the plants but that no such effect was found at the other plants.     

Mortality study of employees in a factory of recovery and refining of catalytic converters in Rome, Italy

The study objective is to describe cause specific mortality of employees in a plant engaged in production, recovery and refining of catalytic converters located in Rome. Previous epidemiological studies conducted in similar plants are not available. A total of 828 workers (642 males and 186 females) were followed up between 1956 and 31-12-2003. Cause specific standardized mortality ratio (SMR) and 90% confidence intervals (CI) were computed using regional rates for comparison. Among males hired between 1956 and 1993, followed up until 31/12/2003, mortality for all causes (SMR 0,8; 90% CI 0,7-1,0; 85 observed) and all neoplasms (SMR 0,6; 90% CI 0,42-0,87; 20 observed) is below expected; an increase is present for liver cirrhosis (SMR 2,74; 90% CI 1,47-5,1; 7 observed) and brain cancer (SMR 5,24; 90% CI 2,3-11,90; 4 observed). The present investigation complies with the proposed scientific standards for occupational cohort studies. The study was not prompted by well defined a priori hypotheses but it is included in a process intended to typify a potentially polluted site; the absence of a priori hypotheses and of previous epidemiological evidence, prevent from a causal interpretation of the increased mortality from liver cirrhosis and brain cancer. The implementation of cohort studies in industrial sites where industrial activities similar to the one here examined are present, are highly recommended.