Distribution of nickel in lungs from former nickel workers

Objective: The purpose of this work was to study the distribution of nickel within lung tissue obtained from nickel-exposed people and to evaluate the␣use of only one single sample for determination of the nickel burden of the lung. Methods and materials: The material used was lung tissue obtained from 15 former nickel refinery workers who had been exposed to a variety of nickel compounds such as Ni₃S₂, NiO, Ni⁰, NiSO₄, and NiCl₂. Ten samples taken from different locations of the lung as well as from the right and left bronchus and from the right lower lobe (total 13 samples per individual) were analyzed for nickel by electrothermal atomic absorption spectrometry. Samples obtained from ten people not connected to the refinery served as a reference group. Results: The arithmetic mean value ± SD for nickel concentration was 50 ± 150 μg g⁻¹ dry wt. Biopsies collected on the center of the lower right lobe had an average nickel concentration of 82 ± 252 μg g⁻¹. The average nickel concentration detected in the right and left bronchus was 5.9 ± 11.6 and 3.8 ± 6.0 μg g⁻¹, respectively. Lung tissue obtained from ten people not connected to the refinery had an average nickel concentration of 0.74 ± 0.44 μg g⁻¹. Conclusions: The significant findings based on log-normal distribution of the nickel concentration were as follows: (1) samples obtained from the right lung showed no significant difference from samples taken from the left lung–a comparison of the nickel concentration detected in all the lung lobes showed that no single lobe differed from another; (2) the concentration of nickel found in the main bronchus of the refinery workers, although elevated, was significantly lower than the concentration detected in the remaining tissue; and (3) one single biopsy did not reflect the nickel burden of the lung. Received: 20 November 1997 / Accepted: 21 April 1998     

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.     

Cancer incidence among Finnish workers exposed to aromatic hydrocarbons

Objectives: To assess whether occupational exposure to aromatic hydrocarbons increases carcinogenic risk. Methods: We followed cancer incidence among 3,922 male and 1,379 female workers monitored for exposure to styrene, toluene, or xylene. The follow-up after the first personal measurement comprised 66,500 person-years at risk over the period 1973–1992. We computed the indirectly standardized incidence ratios (SIR) with 95% confidence interval (CI) with regard to age-, gender-, and period-specific incidence rates of cancer in the Finnish general population. Results: The overall rate of cancer incidence for the total cohort was fairly similar to that of the general population. The risk for nervous system tumors was increased at 10 years after the first personal measurement (SIR 2.80, CI 1.03–6.08). For styrene there was an excess risk for rectal cancer (SIR 3.11, CI 1.14–6.77), and risks for pancreatic and nervous system tumors were increased nonsignificantly. For toluene and xylene, no clear increase in cancer risk was found. Conclusions: The data are not supportive of an overall increase in the cancer risk for these solvents, even though we cannot rule out site-specific associations with the rectum, pancreas, and nervous system. There is supporting evidence in the epidemiology literature for pancreatic cancer risk and heavy exposure to styrene. More studies are warranted on solvents, with detailed information on lifetime exposures and habits being collected whenever possible. Received: 20 March 1997 / Accepted: 27 August 1997     

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.

 

     

Cancer risk among workers at a copper/nickel smelter and nickel refinery in Finland

Summary A total of 1388 workers employed for at least 3 months at a copper/nickel smelter and nickel refinery were followed up for cancer from 1953 to 1987 through the Finnish Cancer Registry. There were 1339 male and 49 female workers, making a total of 27130 and 706 person-years, respectively. All of the women worked in the refinery, which opened in 1960, the same year the smelting of nickel began. A total of 67 cancers were diagnosed among the men, the standardized incidence ratio for all cancers being 1.0. No cancer was found among the women (1.8 expected). The risk of cancer among men was analysed according to primary site, exposure to nickel, type of work, years since first exposure and age at diagnosis. In the subcohort of nickel refinery workers, one case of sinonasal cancer was observed, against 0.02 expected, but otherwise no significantly increased risks of cancer were found. In addition to the small size of the cohort, the non-positive finding concerning lung cancer might be related to the relatively low arsenic exposure and, perhaps, to the late commencement of nickel production.     

Mortality and cancer incidence among a population previously exposed to environmental cadmium

Objectives: This paper evaluates the associations of previous exposure to environmental cadmium (Cd) and renal function with total mortality and cancer incidence. Methods: The study population comprised 275 residents (aged 40–92 years at baseline) in a Cd-polluted area located on Tsushima Island, Nagasaki, Japan. In the study area, the dietary intake of Cd decreased because the soil of the Cd-polluted rice fields was replaced with new soil between 1980 and 1983. The mortality rate from 1982 to 1997 and cancer incidence from 1985 to 1996 were investigated. Standardized mortality and incidence ratios (SMR and SIR) were calculated by using regional reference rates. The associations of renal function and urinary Cd levels with total mortality and cancer incidence were evaluated with Cox regression models. Results: The SMR for all subjects, and those with a urinary β₂-microglobulin (U-β₂M) concentration ≥1,000 μg/g creatinine (Cr) and <1,000 μg/g Cr was estimated at 90 [95% confidence interval (CI) 73–109], 138 (95% CI 101–183) and 66 (95% CI 49–87), respectively. After adjustment for age and other potential confounders, in men, serum β₂M (S-β₂M) (≥2.3 mg/l) and in women, serum Cr (≥1.2 mg/100 ml), relative clearance of β₂M (≥1%) and U-β₂M (≥1,000 μg/g Cr), were associated with a significantly increased risk of mortality, with hazard ratios exceeding 2.0. After further adjustment for log(U-β₂M), the rate ratio of deaths associated with, in men, increased S-β₂M was 2.53 (95% CI 0.97–6.65) and, in women, increased serum Cr (S-Cr) concentrations was 2.75 (95% CI 1.24–6.14). Urinary Cd concentrations (≥10 μg/g Cr) were not significantly associated with mortality. The overall SIR of all malignant neoplasms was 71 (95% CI 44–107). Conclusions: These findings suggest that renal tubule dysfunction and a reduced glomerular filtration rate are predictors of mortality among persons previously exposed to environmental Cd. However, the results also suggest that overall mortality rates in Cd-polluted areas are not necessarily increased, because of the low mortality among those with no, or only slight, signs of low-molecular weight proteinuria. Overall cancer incidence may not be increased among residents in Cd-polluted areas. Received: 6 July 2000 / Accepted: 9 December 2000     

Occupational asthma due to chromium and nickel salts

Background: Exposure to chromium and nickel salts is a poorly characterized cause of occupational asthma. Methods: We describe four patients with work-related asthma due to metallic salts. Skin–prick tests to potassium dichromate and nickel sulfate were performed. The patients underwent methacholine inhalation tests and specific inhalation challenges (SIC) with both chromium and nickel salts. Results: Two patients showed positive skin–prick tests to potassium dichromate and nickel sulfate. All patients had bronchial hyperresponsiveness to methacholine, which increased 24 h after SIC with metallic salts. SIC with potassium dichromate elicited late asthmatic reactions (LAR) in two workers, one subject had an early asthmatic reaction (EAR), and another subject showed a dual asthmatic reaction (DAR). SIC with nickel sulfate induced a DAR in one subject and a late asthmatic reaction in another. Conclusions: Chromium and nickel salts can give rise to occupational asthma in exposed workers. The underlying mechanism may be IgE-mediated in some cases.     

Cancer incidence among priests: 45?years of follow-up in four Nordic countries

Previously published studies on the risk of cancer among male priests have been based on cancer mortality with the exception of one case–control study. The aim of this study was to present estimates of cancer incidence among Nordic male priests. The study cohort for our analyses consisted of 6.5 million men aged 30–64 years old who had participated in any computerised population census in four Nordic countries in 1990 or earlier. Follow-up was done by drawing linkages with the national population and cancer registries. 13,491 priests were identified by their job title codes. We estimated the standardised incidence ratio (SIR) and 95% confidence intervals (95% CI) for the priests using the male population as a reference. Priests had a lower cancer incidence than the general population (overall SIR 0.85, 95% CI: 0.82–0.88). The majority of smoking- and alcohol-related cancers were associated with decreased SIR estimates. Increased risks were observed for skin melanoma (SIR 1.34, 95% CI: 1.11–1.62), acute myeloid leukemia (SIR 1.75, 95% CI: 1.20–2.47) and thyroid cancer (SIR 1.86, 95% CI: 1.22–2.73). This is the first cohort study regarding the incidence of cancer among priests. The lower incidence of smoking and alcohol-related cancers among Nordic male priests can be explained by their lower exposure to cigarettes and alcohol when compared to the general population. A greater risk of melanoma is typical of highly-educated people, but it is unclear why priests should have an increased risk of acute myeloid leukemia or thyroid cancer.     

Risk of lung cancer in workers producing stainless steel and metallic alloys

Objectives: The mortality of workers involved in the production of stainless and alloyed steel from 1968 to 1992 was studied, in order to investigate the risk of lung cancer due to exposure to metals, i.e. iron oxides, chromium and/or nickel compounds. Methods: The study design was a historical cohort mortality study and a nested case-control study concerning lung cancer. Standardized mortality ratios (SMRs) were computed using regional mortality rates as an external reference for comparing observed and expected numbers of deaths, adjusting for age, sex and calendar time. Conditional logistic regression was used to estimate odds ratios (ORs). Occupational exposure was assessed through the complete job histories of cases and controls and a specific job-exposure matrix. Results: The cohort comprised 4,288 male and 609 female workers. The observed overall mortality was significantly lower than expected [649 deaths; SMR = 0.91; 95% confidence interval (CI) 0.84–0.98]. No significant SMR was observed for mortality from lung cancer (54 deaths; SMR = 1.19; CI 0.88–1.55). The case-control study was based on 54 cases and 162 individually matched controls. Smoking habits were available for 71%. No lung cancer excess was observed for exposure to (1) metals and/or their compounds, i.e. iron (OR = 0.94, CI 0.48–1.86), chromium and/or nickel (OR = 1.18, CI 0.62–2.25), and cobalt (OR = 0.64, CI 0.33–1.25), (2) acid mists (OR = 0.43, CI 0.17–1.10), and (3) asbestos (OR =  1.00, CI 0.54–1.86). With respect to exposure to polycyclic aromatic hydrocarbons (PAHs) and silica, which are often found together in workplaces, (1) high and statistically significant lung cancer excesses were observed, the ORs being 1.95 (CI 1.03–3.72) and 2.47 (CI 1.28–4.77) respectively, (2) quantitative exposure parameters revealed upward trends reaching statistical significance (P < 0.05), and (3) adjustments for tobacco consumption did not reveal any confounding factors from smoking. Conclusion: This study failed to detect any relationship between lung cancer and exposure to iron, chromium, nickel and/or their compounds. High and statistically significant relative risks, along with increasing trends, were observed for simultaneous exposure to PAHs and silica. Received: 12 April 1999 / Accepted: 2 October 1999     

Urinary nickel as bioindicator of workers' Ni exposure in a galvanizing plant in Brazil

Objectives: We measured urinary nickel (U-Ni) in ten workers (97 samples) from a galvanizing plant that uses nickel sulfate, and in ten control subjects (55 samples) to examine the association between occupational exposure to airborne Ni and Ni absorption. Methods: Samples from the exposed group were taken before and after the work shift on 5 successive workdays. At the same time airborne Ni (A-Ni) was measured using personal samplers. Ni levels in biological material and in the airborne were determined by a graphite furnace atomic absorption spectrometry validated method. In the control group the urine samples were collected twice a day, in the before and after the work shift, on 3 successive days. Results: Ni exposure low to moderate was detected in all the examined places in the plant, the airborne levels varying between 2.8 and 116.7 μg/m³ and the urine levels, from samples taken postshift, between 4.5 and 43.2 μg/g creatinine (mean 14.7 μg/g creatinine). Significant differences in U-Ni creatinine were seen between the exposed and control groups (Student's t test, P ≤ 0.01). A significant correlation between U-Ni and A-Ni (r = 0.96; P ≤ 0.001) was detected. No statistical difference was observed in U-Ni collected from exposed workers in the 5 successive days, but significant difference was observed between pre- and postshift samples. Conclusions: Urinary nickel may be used as a reliable internal dose bioindicator in biological monitoring of workers exposed to Ni sulfate in galvanizing plants regardless of the day of the workweek on which the samples are collected. Received: 28 January 1999 / Accepted: 10 July 1999     

Methylene dianiline : assessment of exposure and cancer morbidity in power generator workers

Summary The biaromatic amine 4,4'-methylene dianiline (MDA) is an animal carcinogen, possibly also carcinogenic to humans. In a cohort of 595 power generator workers potentially exposed to MDA in a curing agent of an epoxy system, the overall standardised cancer incidence ratio (SIR) among males (n = 550), however, was only 0.52 [95% confidence interval (CI) 0.16–1.21] based on five observed cases. One male urinary bladder cancer case was found in comparison to 0.6 expected (SIR 1.67; 95% CI 0.04–9.31). This case was identified in an unexposed subcohort. High levels of MDA metabolites were ascertained in the urine of currently exposed workers, probably following percutaneous absorption. Although no evidence of an increased overall or bladder cancer risk was detected, the limitations of the study in regard to the size of the cohort, age and cancer latency preclude a definite risk assessment. The dermal absorption of MDA has been highlighted.     

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.

     

Cancer incidence and mortality among temporary maintenance workers in a refinery/petrochemical complex in Korea

Abstract

Background:

Petrochemical plant maintenance workers are exposed to various carcinogens such as benzene and metal fumes. In Korea, maintenance operations in petrochemical plants are typically performed by temporary employees hired as contract workers.

Objectives:

The purpose of this retrospective study was to evaluate cancer risk in temporary maintenance workers in a refinery/petrochemical complex in Korea.

Methods:

Subjects consisted of 14 698 male workers registered in a regional petrochemical plant maintenance workers union during 2002–2007. Cancer mortality and incidence were identified by linking with the nationwide death and cancer registries during 2002–2007 and 2002–2005, respectively. Standardized mortality ratios (SMRs) and standardized incidence ratios (SIRs) were calculated for each cancer.

Results:

Increased SMR 3·61 (six cases, 95% CI: 1·32–7·87) and SIR 3·18 (five cases, 95% CI: 1·03–7·42) were observed in oral and pharyngeal cancers.

Conclusion:

Our findings may suggest a potential association between oral and pharyngeal cancers and temporary maintenance jobs in the petrochemical industry. Future studies should include a longer follow-up period and a quantitative exposure assessment.     

Mortality and cancer incidence among Lithuanian cement producing workers

Aims: To investigate mortality and cancer incidence of cement producing workers.

Methods: A total of 2498 cement workers who have been employed at Portland cement producing departments for at least one year from 1956 to 2000 were followed up from 1 January 1978 to 31 December 2000. The cohort contributed 43 490 person-years to the study. Standardised incidence ratios (SIR) and standardised mortality ratios (SMR) were calculated as ratios between observed and expected numbers of cancers and deaths. The expected numbers were based on sex specific incidence and mortality rates for the total Lithuanian population.

Results: Significantly increased SMRs were found for all malignant neoplasms (SMR 1.3, 95% CI 1.0 to 1.5) and for lung cancer (SMR 1.4, 95% CI 1.0 to 1.9) among male cement workers. SIR for all cancer sites was 1.2 (95% CI 1.0 to 1.4). Excess risk was found for cancer of the lung (SIR 1.5, 95% CI 1.1 to 2.1). The SIR for urinary bladder cancer was also increased (SIR 1.8, 95% CI 0.9 to 3.5). The overall cancer incidence was not increased among females (SIR 0.8, 95% CI 0.6 to 1.1). With increasing cumulated exposure to cement dust, there were indications of an increasing risk of lung and stomach cancers among males.

Conclusions: This study supported the hypothesis that exposure to cement dust may increase the lung and bladder cancer risk. A dose related risk was found for stomach cancer, but no support was found for an increased risk of colorectal cancer.

     

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 in the Swedish leather tanning industry: updated findings 1958-99

Aims: To assess how a 10 year extension of the follow up period affected cancer incidence in the Swedish leather tanning cohort.

Methods: A cohort of 2027 tannery workers (of which 482 were women) who had been employed for at least one year between 1900 and 1989 at one of three Swedish leather tanneries, was established. The start of observation varied between 1958 and 1966 for the three plants. Through linkage with the Swedish Cancer Registry, incident cancer cases were recorded up to 1999. Cause specific expected cancer incidence was calculated for 1958–99 based on calendar year, sex, and five year age group specific incidence rates for the counties where the plants had been located. Altogether 56 022 person-years at risk were generated.

Results: A total of 351 incident cancer cases were observed compared to 302 expected, which resulted in an increased standardised incidence ratio (SIR) of 1.16 (95% CI 1.04 to 1.29). An enhanced risk for prostate cancer was observed (SIR 1.44, 95% CI 1.10 to 1.86), mainly attributable to the later part of the observation period (1990–99). In this updated analysis the previously observed risk excess for soft tissue sarcomas was no longer significant (SIR 2.62, 95% CI 0.96 to 5.70). For multiple myelomas and sinonasal cancer the slight non-significant excesses remained, still based on very few cases.

Conclusions: The increased risk for prostate cancer in the present study might be a chance finding, but is noteworthy, since it is in acccordance with the finding of increased SIR for prostate cancer among leather workers in another recent Swedish study. Moreover, excess risks for prostate cancer among farmers have been reported, indicating pesticides as possible causative agents. Leather tanners have also been exposed to pesticides.

     

A mortality study among workers in a French aluminium reduction plant

Objective: A mortality study on the association between lung cancer and occupational exposure to polycyclic aromatic hydrocarbons (PAHs) was carried out in a French aluminium reduction plant. This study updated a previous mortality study. Method: The historical cohort included every male worker who had been employed in the plant for at least 1 year between 1950 and 1994. Workers were followed-up for mortality from 1968 to 1994. Causes of death were obtained from death certificates. Standardised mortality ratios (SMRs) and 95% confidence intervals (CI) were computed using regional mortality rates as external reference to compare observed and expected numbers of deaths, adjusted for gender, age and calendar time. Results: The cohort comprised 2,133 men, of whom 335 died during the follow-up period. The observed mortality was lower than expected for all causes of death (SMR=0.81, CI 0.72–0.90) and for lung cancer (observed=19, SMR=0.63, CI 0.38–0.98). No lung cancer excess was observed in workshops where PAH exposure was likely to have occurred, and no trend was observed according to duration of exposure and time since first exposure. This low lung cancer mortality could be partly explained by a marked healthy worker effect and a possible negative confounding by smoking. An excess was observed for bladder cancer (observed=7, SMR=1.77, CI 0.71–3.64) in the whole cohort, that was higher among workers employed in workshops where PAH exposure was likely to have occurred (observed=6, SMR=2.15, CI 0.79–4.68). In addition, an SMR higher than unity was observed for “psychoses and neuro-degenerative diseases” (observed=6, SMR=2.39, CI 0.88–5.21), that could not be related to occupational aluminium exposure. Conclusion: No lung cancer risk was detected. Non-significant excesses were observed for bladder cancer and for psychoses and neuro-degenerative diseases. Received: 11 June 1999 / Accepted: 22 January 2000     

Carcinogenicity of occupational nickel exposures: an evaluation of the epidemiological evidence

The health effects documented in recent epidemiological studies of nickel-exposed workers relate to past exposures, mostly of unknown magnitude and unknown nickel speciation. Major studies have been carried out at nickel smelters and refineries. Although each study suffers from some deficiencies, as is common in such retrospective studies, the findings in concert strongly indicate that nickel emitted from the calcining and sintering operations is a potent carcinogen resulting in nasal and pulmonary cancers. Some risk appears to be present in other refinery operations, such as Orford furnace, copper and nickel sulfate, and crushing departments, and one study has suggested a risk associated with soluble nickel compounds in the electrolysis department, although this finding has not been confirmed. Only one study demonstrated an exposure-response relationship, which, however, was not statistically significant. Other studies showed a relationship between increased exposure time and augmented cancer risk. In nickel-using industries, no excess cancer related to nickel exposures has been demonstrated beyond doubt; concurrent exposures to other potential carcinogens constitute a confounding variable that makes interpretation difficult. However, the studies have not excluded that a cancer hazard may be present outside the nickel-producing facilities. Further, case-referent studies of respiratory cancers suggest that a nickel-related etiology may well exist in the nickel-using industries. As the exact identity of the carcinogenic form or forms of nickel remains unknown, exposure to all nickel compounds should be kept as low as reasonably achievable.     

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).     

Mortality and cancer incidence in a Swedish art glassworks—an updated cohort study

Aim: To study mortality and cancer incidence, in a Swedish art glassworks producing both heavy and semi-crystal glassware, in an extended cohort of workers over a long time period during which some preventive actions had taken place.Methods: In the updated study, 1,229 men and women were eligible as cohort members during the period 1964–1997. The observed number of cases was compared with expected numbers, as calculated from cause-, age-, gender- and calendar year-specific national rates for mortality and cancer incidence.Results: Among men only, a significant risk was seen for cancer incidence in the colon and rectum [standardised incidence ratio (SIR) 1.92, 95% confidence interval (CI) 1.05–3.23; 14 cases] and increased, but statistically non-significant, risks were also seen for male cases of tumours in the liver/bile ducts and brain. Among women, statistically non-significant risks were seen for tumours in the liver/bile ducts and in the lymphatic and haematopoietic systems. No increased risk for cancer of the lung was found in this updated study. The risk for cancer in the colon/rectum was slightly increased in all work categories, and the increase was statistically significant among male and female unspecified glassworkers (SIR 3.13, 95% CI 1.35–6.16; five male and three female cases). A statistically significantly increased risk for cancer in the liver/bile ducts was seen among refinement workers (SIR 3.96, 95% CI 1.07–10.14; two male and two female cases).Conclusion: Most of the causes of death associated with an elevated standardised mortality ratio (SMR) in the 1985 cohort resulted in lower SMRs in this updated cohort, maybe as a consequence of preventive actions taken at the glassworks. On the other hand, the risk for cancers in the digestive system seems to remain, perhaps due to past asbestos exposure or inhalation/digestion of larger particles in the ambient air.