Mortality and cancer incidence in Swedish battery workers exposed to cadmium and nickel

OBJECTIVE: To follow up cancer incidence and mortality in a group of Swedish battery workers exposed to nickel hydroxide and cadmium oxide. METHODS: 869 workers, employed at least one year between the years 1940 and 1980 were followed up until 1992. Vital status and causes of death were obtained from the Swedish cause of death registry. Cancer morbidity was retrieved from the Swedish cancer registry. Regional reference rates were used to compute the expected numbers of deaths and cancers. RESULTS: Up to 31 December, 1992, a total of 315 deaths (292 in men and 23 in women) had occurred in the cohort. For men, the overall standardised mortality ratio (SMR) was 106 (95% confidence interval (95% CI) 93.7 to 118) and for women 83.8 (95% CI 53.1 to 126). The SMRs for total cancer mortality were 125 (95% CI 98.2 to 157) for men and 69.5 (95% CI 25.5 to 151) for women. The SMR for lung cancer in men was 176 (95% CI 101 to 287). No lung cancers were found among female workers. Up to 31 December, 1991, a total of 118 cancers had occurred in the cohort. A significantly increased standardised incidence ratio (SIR) was found for cancer of the nose and nasal sinuses in men, three cases v 0.36 expected, yielding an SIR of 832 (95% CI 172 to 2430). Applying a 10 year latency period in cohort members exposed to > or = 1000 micrograms cadmium/m3, the SIR was 1107 (95% CI 134 to 4000). Similarly, for cohort members exposed to 2000 micrograms nickel/m3, the SIR was 1080 (95% CI 131 to 3900). CONCLUSION: There was an increased overall risk for lung cancer, but no exposure-response relation between cumulative exposure to cadmium or nickel and risk of lung cancer. There was a highly significant increased risk of cancer of the nose and nasal sinuses, which may be caused by exposure to nickel or cadmium or a combination of both exposures.

 

     

Update of cancer incidence among workers at a copper/nickel smelter and nickel refinery

Objectives: To assess cancer risk among nickel-exposed workers. Methods: We updated cancer incidence among 1388 workers employed for at least 3 months at a copper/nickel smelter and nickel refinery in Harjavalta, Finland. There were 1155 workers exposed to nickel during the period 1960–1985 in the smelter (566 workers), repair shop (239 workers), or refinery (418 workers). Cancer incidence was followed through the files of the Finnish Cancer Registry up to 31 December 1995. For overall cancer and for a priori selected specific cancer types the ratio of observed to expected numbers of cases was computed as a standardized incidence ratio (SIR), controlled for age, gender, and calendar period and using the region-specific rates as a reference. Results: The overall cancer incidence among both nickel-exposed and unexposed subcohorts was at the expected level. A small increase in lung cancer incidence, which reached statistical significance among workers with a latency exceeding 20 years, was observed among the smelter workers exposed to insoluble nickel compounds. Among workers in the refinery, who were exposed primarily to nickel sulfate at levels below 0.5 mg/m³ as well as to low concentrations of other nickel compounds, there was an increased risk for nasal cancer (SIR 41.1, 95% CI 4.97–148), positively associated with latency and duration of employment, and an excess risk for stomach (SIR 4.98, 95% CI 1.62–11.6) and lung (SIR 2.61, 95% CI 0.96–5.67) cancers. Conclusions: Since elevated nasal and lung cancer risks were confined to the refinery, where the primary exposure was to nickel sulfate, it is likely that nickel sulfate is mainly responsible for the elevated respiratory cancer risk. We cannot rule out whether the excess stomach cancer risk is a chance finding, or related to the working environment. Received: 11 September 1997 / Accepted: 17 October 1997     

Exposure to nickel compounds and smoking in relation to incidence of lung and nasal cancer among nickel refinery workers.

OBJECTIVES: To investigate the relation between occupational hazards among nickel refinery workers and their exposure to different forms of nickel over time and the interaction between smoking and total exposure to nickel. METHODS: The cohort consisted of 379 workers with first employment 1916-40 and at least three years of employment and 4385 workers with at least one year of employment 1946-83. Data on smoking (ever or never) were available for almost 95% of the cohort. Two analyses were used, indirect standardisation from observed and expected numbers and Poisson regression. RESULTS: During the follow up 1953-93, 203 new cases of lung cancer were observed v 68 expected (standardised incidence ratio (SIR) 3.0, 95% confidence interval (95% CI) 2.6-3.4) and 32 cases of nasal cancer were observed v 1.8 expected (SIR 18.0, 95% CI 12-25). The Poisson regression analysis showed an excess risk of lung cancer in association with exposure to soluble forms of nickel, with a threefold increase in relative risk (RR) (P < 0.001) and a multiplicative effect of smoking and exposure to nickel. The RRs were 1.1 (95% CI 0.2-5.1) for exposed workers who had never smoked and 5.1 (95% CI 1.3-20.5) for exposed workers who smoked. CONCLUSION: It is not possible to state with certainty which specific nickel compounds are carcinogenic, but a significant excess risk was found for workers exposed to soluble nickel alone or in combination with other forms of nickel. The present study suggests a multiplicative effect of smoking and nickel exposure.     

A mortality study of nickel/chromium platers

The mortality experienced by a cohort of 2689 nickel/chromium platers between 1946 and 1983 has been investigated. All members of the study cohort had some period of chrome exposed employment. Overall, compared with the general population of England and Wales, statistically significant differences relating to cancer were found for cancer of the stomach (E = 16.2, O = 25), primary cancer of the liver (E = 0.8, O = 4), cancer of the nose and nasal cavities (E = 0.3, O = 3), cancers of the lung and bronchus (E = 48.1, O = 72), and all cancers (E = 164.2, O = 213). Chrome bath workers are the more heavily exposed workers, and a striking difference in SMRs was found for lung cancer among men first employed as chrome bath workers (SMR = 199) and men first employed as other chrome workers (SMR = 101). The method of regression models in life tables (RMLT) was used to compare the durations of chrome exposed employment of those dying from causes of interest with those of all matching survivors in the same year of follow up, while controlling for sex, and for year and age of starting employment. Significant positive associations were found only for cancers of the lung and bronchus and duration of chrome bath work. In this study exposure to nickel was shown not to be an important confounding exposure.     

A mortality study of nickel/chromium platers.

The mortality experienced by a cohort of 2689 nickel/chromium platers between 1946 and 1983 has been investigated. All members of the study cohort had some period of chrome exposed employment. Overall, compared with the general population of England and Wales, statistically significant differences relating to cancer were found for cancer of the stomach (E = 16.2, O = 25), primary cancer of the liver (E = 0.8, O = 4), cancer of the nose and nasal cavities (E = 0.3, O = 3), cancers of the lung and bronchus (E = 48.1, O = 72), and all cancers (E = 164.2, O = 213). Chrome bath workers are the more heavily exposed workers, and a striking difference in SMRs was found for lung cancer among men first employed as chrome bath workers (SMR = 199) and men first employed as other chrome workers (SMR = 101). The method of regression models in life tables (RMLT) was used to compare the durations of chrome exposed employment of those dying from causes of interest with those of all matching survivors in the same year of follow up, while controlling for sex, and for year and age of starting employment. Significant positive associations were found only for cancers of the lung and bronchus and duration of chrome bath work. In this study exposure to nickel was shown not to be an important confounding exposure.     

Mortality experience among employees at a hydrometallurgical nickel refinery and fertiliser complex in Fort Saskatchewan, Alberta (1954-95)

OBJECTIVE—To study the mortality experience of workers at a hydrometallurgical nickel refinery and fertiliser complex in Fort Saskatchewan, Alberta, Canada.
METHODS—A total of 1649 male employees of Sherritt International who worked for at least 12 continuous months during the years 1954 to 1978 at the Fort Saskatchewan, Alberta hydrometallurgical nickel refinery and fertiliser complex were followed up for an additional 17 years. Mortality was ascertained from the Canadian mortality data base maintained by Statistics Canada and covered the years 1954-95. Statistics were analysed with Monson's computer program.
RESULTS—Total mortality, when compared with the Canadian population, was significantly below expectation. Fewer deaths were found for circulatory disease, ischaemic heart disease, respiratory disease, neoplasms, digestive cancer, and accidents, poisonings, and violence. Among the 718 men in the group exposed to nickel, there were no deaths due to nasal cavity or paranasal sinus cancer. Fewer deaths were found for all causes, circulatory disease, ischaemic heart disease, neoplasms and digestive cancer. Lower death rates were observed than expected for respiratory malignancies and cancer of the bronchus and lung.
CONCLUSION—No association was found in this study between exposure to nickel concentrate or metallic nickel in the hydrometallurgical refining process and the subsequent development of respiratory cancer.


Keywords: epidemiology; nickel workers; mortality     

Determination of nickel in lung specimens of thirty-nine autopsied nickel workers

Summary Lung specimens from 39 nickel refinery workers autopsied during the period from 1978 to 1984 were analyzed for nickel. Fifteen of the workers were employed in the Roasting and Smelting Department, where exposure to nickel was predominantly in the form of nickel-copper oxides, Ni₃S₂ and metallic dust. The remaining 24 men worked in the Electrolysis Department. Exposure in this group was considered to be mostly to the water-soluble compounds, NiSO₄ and NiCl₂, but also to a lesser degree to water-insoluble nickel compounds such as nickel-copper oxides and sulphides. The arithmetic mean ± SD for nickel concentration in lung tissues expressed in gg^–1 dry wt for the 39 workers was 150 ± 280. In the workers employed in the Roasting and Smelting Department, the average nickel concentration was 330 ± 380; for those who worked in the Electrolysis Department it was 34 ± 48. Lung tissue from 16 autopsied persons not connected with the refinery had an average nickel concentration of 0.76 ± 0.39. Statistical analysis based on log-normal distributions of the measured nickel concentrations allowed three major conclusions to be formulated: (1) nickel refinery workers exhibit elevated nickel levels in lung tissues at autopsy; (2) workers of the Electrolysis Department and the Roasting Smelting Department constitute distinct groups with respect to the accumulation of nickel in lung tissue; (3) workers who were diagnosed to have lung cancer had the same lung nickel concentrations at autopsy as those who died of other causes.     

Cancer risk among glass factory workers: an excess of lung cancer?

A total of 3749 workers employed for at least three months in two Finnish glass factories (cohorts A and B) were followed up for cancer in 1953-86 through the Finnish Cancer Registry. In cohort A (1353 men, 1261 women), 106 primary cancers were diagnosed among men, and their standardised incidence ratio (SIR) for all cancers was 99. Among women the risk was low (65 cases, SIR 64). In cohort B (450 men, 685 women), the relative risk of cancer was close to unity for both men (57 cases) and women (75 cases). The risk of cancer was analysed by primary site, type of work, years since first exposure, and age at diagnosis. The only significantly increased risks were those of lung cancer among men (SIR 130, 95% CI 100-167, cohorts A and B combined), and skin cancer among glass blowers (SIR 625, 95% CI 129-1827). An increased risk of lung, stomach, and colon cancer as well as of brain tumours has been reported in previous studies. It is postulated that the excess risk of lung cancer, detected in this study, can also be accounted for by lifestyle, and not only by possible occupational exposures, because a similar excess risk of lung cancer has been found previously for all industrial workers in Finland. Although the risk of stomach cancer in this study was increased among glass blowers, it was not high in the largest groups of plain glass workers. The risks of tumours of the central nervous system and colon were not increased either.     

Cancer risk among glass factory workers: an excess of lung cancer?

A total of 3749 workers employed for at least three months in two Finnish glass factories (cohorts A and B) were followed up for cancer in 1953-86 through the Finnish Cancer Registry. In cohort A (1353 men, 1261 women), 106 primary cancers were diagnosed among men, and their standardised incidence ratio (SIR) for all cancers was 99. Among women the risk was low (65 cases, SIR 64). In cohort B (450 men, 685 women), the relative risk of cancer was close to unity for both men (57 cases) and women (75 cases). The risk of cancer was analysed by primary site, type of work, years since first exposure, and age at diagnosis. The only significantly increased risks were those of lung cancer among men (SIR 130, 95% CI 100-167, cohorts A and B combined), and skin cancer among glass blowers (SIR 625, 95% CI 129-1827). An increased risk of lung, stomach, and colon cancer as well as of brain tumours has been reported in previous studies. It is postulated that the excess risk of lung cancer, detected in this study, can also be accounted for by lifestyle, and not only by possible occupational exposures, because a similar excess risk of lung cancer has been found previously for all industrial workers in Finland. Although the risk of stomach cancer in this study was increased among glass blowers, it was not high in the largest groups of plain glass workers. The risks of tumours of the central nervous system and colon were not increased either.     

Exposure to soluble nickel in electrolytic nickel refining

Past and present exposure to nickel was studied in an electrolytic nickel refinery, where an increased incidence of nasal cancer had been reported, using nickel analyses in air, blood and urine. Genotoxic effects were studied using analysis of micronuclei from acridine orange-stained smears from the buccal mucosa of the workers. Workers used respirators or masks in tasks where the exposure was expected to be high. Inside the mask, nickel concentrations were 0.9–2.4 μg m⁻³ in such tasks. In those tasks where masks were not used, nickel concentrations in the breathing zone were 1.3–21μgm⁻³. Air-borne nickel concentrations (stationary sampling) varied between 230 and 800μg m⁻³ in 1966–1988 with no systematic change; thereafter lower concentrations (170–460μg m⁻³) have been observed. After-shift urinary concentrations of nickel were 0.1–2 μmoll⁻¹ they showed no correlation with nickel concentrations in the air. Concentrations of nickel in the urine were still elevated after a 2–4 week vacation. The frequency of micronucleated epithelial cells in the buccal mucosa of nickel refinery workers was not significantly elevated by comparison with referents. No relationship was observed between micronucleus frequencies and levels of nickel in air, urine or blood.     

A study of mortality in workers engaged in the mining, smelting, and refining of nickel. II: Mortality from cancer of the respiratory tract and kidney

This paper describes observed and expected mortality from cancers of the lung, larynx, nose, and kidney in a cohort of 54,509 nickel workers followed for 35 years. For analysis purposes the cohort was subdivided into men with and without service in one of the three high nickel dust areas of the operation: the Sinter Plants at Copper Cliff and Coniston, and the Leaching, Calcining and Sintering (LC&S) department at Port Colborne. At Copper Cliff Sinter Plant workers experienced three times the expected number of lung cancer deaths; the SMR rose steeply with increasing duration of service peaking at 943 with 10 to 15 years. A similar overall excess risk of lung cancer was seen in the smaller Coniston Sinter Plant again with an indication of an exposure risk gradient. Men in the LC&S department at Port Colborne also experienced a dose related excess risk of lung cancer death that rose to an SMR of 806 with 20 to 25 years of service. Nasal cancer deaths were increased at both the Copper Cliff Sinter Plant (6 deaths) and the LC&S department at Port Colborne (19 deaths), representing SMRs of 3,704 and 7,755, respectively, for this rare cancer. Laryngeal cancer and kidney cancer, both previously associated with nickel, were not in excess in these high risk groups. A further exploration of death from these causes in the lower exposure remainder of the cohort revealed an epidemiologically modest elevation in lung cancer death in miners (probably not nickel related) and parts of the Copper Refinery. No evidence of laryngeal cancer excess was found.(ABSTRACT TRUNCATED AT 250 WORDS)     

Persisting risk of nickel related lung cancer and nasal cancer among Clydach refiners

Objective

To evaluate the risk of lung cancer and nasal cancer among workers employed at the Clydach nickel refinery, South Wales since 1930 by combining data from the two most recently published papers on this cohort.

Methods

Observed and expected numbers of cancer deaths were extracted for workers who had a minimum of five years service and were employed for the first time between 1902 and 1992. Standardised mortality ratios (SMR) were calculated for subgroups according to year of employment, time since first employment, and process work.

Results

A persisting excess of respiratory cancer was found for workers employed in the period 1930–92, with a lung cancer SMR of 133 (95% CI 103 to 172) and a SMR for nasal cancer of 870 (95% CI 105 to 3141). The lung cancer excess was most clearly seen 20 years or more after first employment and seemed to be confined to process workers. There was no indication of a further reduction in risk since 1930.

Conclusion

The extreme nickel related cancer hazard at the refinery before 1920 was greatly reduced during subsequent years. Some of the carcinogenic exposures seem to have remained after 1930, producing an elevated risk of nasal cancer and a 30% excess of lung cancer in the workforce. There was evidence of a persisting risk among process workers first employed since 1953.     

Cancer incidence of workers in the Swedish petroleum industry.

OBJECTIVES: To estimate the risk of cancer due to occupational exposure to petroleum products in the Swedish transport and refinery industries. METHODS: In a retrospective cohort study the cancer incidence in 4128 men and 191 women, who had worked for at least one year in the petroleum industry, was compared with the incidence in the general population. The job titles and employment times for each person were found in personal files in the industries. The men had on average worked in jobs exposed to petroleum for 11.6 years at the end of the observation period. The cases of cancer were identified by record linkage with the Swedish cancer register. RESULTS: In total there were 146 cases of cancer v 157.6 expected (standardised mortality ratio (SMR) 0.93 90% confidence interval (90% CI) 0.80 to 1.1). Operators at refineries had an increased risk of leukaemia (6 cases v 1.7 expected, 90% CI of relative risk (RR) 1.5 to 7.0). Five of the six cases had started to work at the refineries in the 1950s or later. No other significantly increased risk of cancer was found. Distribution workers had a decreased incidence of lung cancer (no cases, 90% CI of RR 0 to 0.4). CONCLUSIONS: Operators at Swedish refineries had an increased risk of leukaemia. A possible cause is exposure to benzene. There was no increased risk of leukaemia in distribution workers. Distribution workers had a decreased risk of lung cancer.     

Lung cancer in workers in a nickel refinery

ABSTRACT This study is an analysis of the occurrence of lung cancer in nickel workers, particularly with regard to development time, histological types and tobacco smoking, in addition to specific exposure to nickel dust and fumes. It is a continuation of previous work in this field (Kreyberg, 1954a, b; 1962, 1969). The series consists of 44 cases of lung cancer occurring during the years 1948-74 in people currently or previously employed at Falconbridge nickel refinery. A seven-year period of reduced activity during the war enables lung cancer in workers who took up employment in 1927-39 to be compared with that in workers who started in or after 1946. It is confirmed that exposure to nickel dust and fumes increases the risk of developing lung cancer. However, all subjects with small cell anaplastic carcinoma and at least 25 out of 28 subjects with epidermoid carcinoma had been tobacco smokers. Four smokers and four non-smokers had Group II tumours. The mean age at diagnosis of lung cancer in the nickel workers corresponds closely with that of male subjects with lung cancer in general, in spite of the very wide differences in the development time, if this is related to the employment time in the refinery alone. The mean age at diagnosis is, however, consistent if the development time is related to the length of tobacco smoking. Tobacco smoking is an important factor in the development of lung cancer in nickel workers, and under the conditions described in this study the reduced carcinogenic influence may be attributable to reduced exposure to nickel and possibly also to tobacco.     

Mortality patterns among petroleum refinery and chemical plant workers

A historical cohort study was conducted to evaluate the mortality experience of 6,831 employees of the Shell Oil Company, Deer Park, Texas, petroleum refinery and chemical plant with emphasis on cancer mortality. Subjects were all workers with potential plant exposure who were employed for at least 3 months during 1948-72. Vital status was determined as of 12/31/83 for 98% of the cohort and death certificates were obtained for 95.4% of 1,180 observed deaths. The statistical analyses excluded 159 female study members. For all causes of death combined, all cancers combined, and for most of the nonmalignant disease categories examined, there were deficits in mortality among refinery workers, chemical plant workers, and workers with experience in both areas. These deficits were generally most pronounced for chemical plant workers. An analysis of specific cancer sites revealed patterns of increased risk suggestive of a possible relationship between occupational exposures in the refinery and lympho-reticulosarcoma. Patterns of increased risk were also observed among chemical plant workers for a category of lymphopoietic tissue cancers, including multiple myeloma, myelofibrosis, polycythemia vera, and certain non-Hodgkin's lymphomas. Some very limited evidence of a possible workplace association was also found among refinery workers for leukemia and cancers of the central nervous system and biliary passages/liver. No evidence was found of an increased risk for cancer of the respiratory system or stomach or for malignant melanoma. A work history review of all suspect cancer excesses failed to identify any common work areas, job assignments, or exposure potentials, although the lack of detailed data on specific chemical exposures precluded accurate assessments of exposure-response.     

Respiratory cancer in a cohort of nickel sinter plant workers.

A study was undertaken of a cohort of nickel refinery workers from a sinter plant that operated from 1948 to 1962. A complete follow-up of the 495 workers has been carried out by searching death records and other measures. Incidence cases known to the Workmen's Compensation Board of Ontario have been included. Fifty-four cases of lung cancer and eight of sinus cancer (including two in men who subsequently developed primary lung cancer) were located. The risk of lung and sinus cancer was much higher in the earlier days of operation of the plant, with an increase rate of over 40% for those employed in the first year of operation. The dose-response relationship has been examined by regressions of standardised morality ratios (SMR) and standardised incidence ratios (SIR). The SIR suggests that the risk doubled at levels of exposure of 12 months (six months in the earlier years).     

Investigations on the quantitative determination of nickel and chromium in human lung tissue

Summary Nickel (Ni) and some of its relatively insoluble compounds as well as chromates may be able to induce cancer in the region of the lungs, as well as in the nose and paranasal sinuses after occupational exposure. Latency periods may amount to 20 years and more. The results of recent investigations have shown that these metals cumulate in the lung tissue after inhalation of relatively insoluble chromium and nickel compounds. The quantitative detection of these heavy metals in samples of pulmonary tissue hence permits the amount of past exposure to be estimated. To establish the normal values, samples of pulmonary tissue from 30 normal subjects were investigated for chromium and nickel content. The samples were taken from different segments and lobes of the lungs, taking topographical anatomical criteria into consideration. In addition, 15 persons who had formerly been exposed to nickel and/or chromium (11 nickel refinery workers, of whom 10 had died of lung cancer, 2 stainless steel welders, 1 foundry worker, 1 electrical technician) were also investigated. From the results of 495 tissue samples from the normal group, median chromium concentrations between 130 and 280 ng/g were calculated, with median nickel concentrations of 20–40 ng/g (wet weight). If these values are related to the nickel concentrations measured in refinery workers, values 112-5,860 times higher were found. The concentrations were about 500 times higher than normal for nickel, and about 60 times higher than normal for chromium in the stainless steel welders. For the foundry workers who died of lung cancer, chromium and nickel concentrations in the normal range were calculated, with the exception of the nickel concentrations in the upper and lower lobes of the right lung. The very high nickel concentrations found in the samples of lung tissue from former nickel refinery workers should be regarded as a guideline with regard to the appraisal of the causal relationship between lung cancer and occupational exposure to relatively insoluble nickel compounds. This result is also supported by epidemiological investigations on this subgroup and must thus be considered etiologically conclusive. For the welders, chromium and nickel concentrations were found that were markedly above normal, but as yet there is no epidemiologically reliable verification for the increased occurrence of malignancies in this occupational group. On the basis of present scientific knowledge, no indications were found of relevant chromium and/or nickel exposure of the lung tissue that might be able to induce lung cancer in either foundry workers or for electric technicians.Dedicated to Professor V. Becker on his 65th birthday     

Study of cancer incidence among 6363 male workers in four Norwegian ferromanganese and silicomanganese producing plants

OBJECTIVES: Little has been known about the risk of cancer associated with occupational exposure to manganese. The objective of this study was therefore to examine the associations between duration of specific work and cancer incidence among employees in four Norwegian ferromanganese and silicomanganese producing plants. METHODS: Among men first employed in 1933-91 and with at least 6 months in these plants, the incident cases of cancer during 1953-91 were obtained from The Cancer Registry of Norway. The numbers of various cancers were compared with expected figures calculated from age and calendar time specific rates for Norwegian men during the same period. Internal comparisons of rates were performed with Poisson regression analysis. The final cohort comprised 6363 men. RESULTS: A total of 607 cases of cancer were observed against 596 cases expected (standardised incidence ratio (SIR) 1.02). Internal comparisons of rates showed a positive trend between the rate of all cancers and duration of furnace work. A slightly weaker trend was also found for duration of blue collar non-furnace work when lags of 25 or 30 years were applied in the analyses. However, several results indicated that the incidence of all cancers among the non- furnace workers decreased during the period of active employment. CONCLUSIONS: Furnace and non-furnace workers may have exposures that increase the incidence of several cancers. The low incidence of cancer among non-furnace workers during the period of ongoing exposure cannot be explained. As this study cannot identify any causal factors, the role of exposure to manganese remains unclear.

 

     

Asbestos exposure and cancer mortality among petroleum refinery workers: a Poisson regression analysis of updated data

The authors investigated the relationship between asbestos exposure and respiratory cancer mortality among maintenance workers and other blue-collar workers at an Italian oil refinery. The cohort contained 931 men, 29,511 person-years, and 489 deaths. Poisson regression analysis using white-collar workers as an internal referent group provided relative risk estimates (RRs) for main causes of death, adjusted for age, age at hiring, calendar period, length of exposure, and latency. Among maintenance workers, RRs for all tumors (RR = 1.50), digestive system cancers (RR = 1.41), lung cancers (RR = 1.53), and nonmalignant respiratory diseases (RR = 1.71) were significantly increased (p < 0.05); no significant excess was found for all causes and among maintenance (RR = 1.12) and other blue-collar workers (RR = 1.01). Results confirm the increased risk of death from respiratory diseases and cancer among maintenance workers exposed to asbestos, whereas other smoking-related diseases (circulatory system) were not statistically different among groups.     

Asbestos Exposure and Cancer Mortality among Petroleum Refinery Workers: A Poisson Regression Analysis of Updated Data

The authors investigated the relationship between asbestos exposure and respiratory cancer mortality among maintenance workers and other blue-collar workers at an Italian oil refinery. The cohort contained 931 men, 29,511 person-years, and 489 deaths. Poisson regression analysis using white-collar workers as an internal referent group provided relative risk estimates (RRs) for main causes of death, adjusted for age, age at hiring, calendar period, length of exposure, and latency. Among maintenance workers, RRs for all tumors (RR = 1.50), digestive system cancers (RR = 1.41), lung cancers (RR = 1.53), and nonmalignant respiratory diseases (RR = 1.71) were significantly increased (p 0.05); no significant excess was found for all causes and among maintenance (RR = 1.12) and other blue-collar workers (RR - 1.01). Results confirm the increased risk of death from respiratory diseases and cancer among maintenance workers exposed to asbestos, whereas other smoking-related diseases (circulatory system) were not statistically different among groups.