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The aim of this paper is to present a paradigm for combining ordinal expert ratings with exposure measurements while accounting for a between-worker effect when estimating exposure group (EG)-specific means for epidemiological purposes. Expert judgement is used to classify the EGs into a limited number of exposure levels independently of the exposure measurements. The mean exposure of each EG is considered to be a random deviate from a central exposure rating-specific value. Combining this approach with the standard between-worker random effect model, we obtain a nested two-way model. Using Gibbs sampling, we can fit such models incorporating prior information on components of variance and modelling options to the rating-specific means. An approximate formula is presented estimating the mean exposure of each EG as a function of the geometric mean of the measurements in this EG, between and within EG standard deviations and the overall geometric mean, thus borrowing information from other EGs. We apply this paradigm to an actual data set of dust exposure measurements in a steel producing factory. Some EG-specific means are quite different from the estimates including the ratings. Rating-specific means could be estimated under different hypotheses. It is argued that when setting up an expert rating of exposures it is best done independently of existing exposure measurements. The present model is then a convenient framework in which to combine the two sources of information.

Objectives: To study the mortality from lung cancer from exposures to hard metal dust at an industrial site producing hard metals--pseudoalloys of cobalt and tungsten carbide--and other metallurgical products many of which contain cobalt., Methods: A historical cohort was set up of all subjects who had worked for at least 3 months on the site since its opening date in the late 1940s. A full job history could be obtained for 95% of the subjects. The cohort was followed up from January 1968 to December 1992. The exposure was assessed by an industry specific job exposure matrix (JEM) characterising exposure to hard metal dust from 1 to 9 and other possibly carcinogenic exposures as present or absent. Smoking information was obtained by interview of former workers. Standard lifetable methods and Poisson regression were used for the statistical analysis of the data., Results: Mortality from all causes was close to the expected (standardised mortality ratio (SMR) 1.02, 399 deaths) whereas mortality from lung cancer was significantly increased among men (SMR 1.70; 46 deaths, 95% confidence interval (95% CI) 1.24 to 2.26). By workshop, lung cancer mortality was significantly higher than expected in hard metal production before sintering (SMR 2.42; nine deaths; 95%CI 1.10 to 4.59) and among maintenance workers (SMR 2.56; 11 deaths; 95%CI 1.28 to 4.59), whereas after sintering the SMR was lower (SMR 1.28; five deaths; 95%CI 0.41 to 2.98). The SMR for all exposures to hard metal dust at a level >1 in the JEM was in significant excess (SMR 2.02; 26 deaths; 95%CI 1.32 to 2.96). The risks increased with exposure scores, duration of exposure, and cumulative dose reaching significance for duration of exposure to hard metal dust before sintering, after adjustment for smoking and known or suspected carcinogens., Conclusion: Excess mortality from lung cancer was found among hard metal production workers which cannot be attributed to smoking alone. This excess occurred mostly in subjects exposed to unsintered hard metal dust.

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 0.713.64) 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.

An industry-wide mortality study on the association between lung cancer and occupational exposure to cobalt and tungsten carbide was carried out in the French hard-metal industry. This case-control study was nested in the historical cohort of workers ever employed in this industry's 10 facilities, most of which are located in eastern France. Workers were followed up from 1968 to 1991. Occupational exposure was assessed using a job-exposure matrix that provided semiquantitative scores for 320 job periods. These scores were significantly correlated with the levels of cobalt measured in 744 historical air samples. In this cohort, which comprised 5,777 males and 1,682 females, the death rate from lung cancer was significant (63 deaths, standardized mortality ratio=1.30, 95% confidence interval (CI) 1.00-1.66) when compared with national death rates. Sixty-one cases and 180 controls were included in the study. When the exposures during the last 10 years were ignored, a twofold lung cancer risk was observed among workers simultaneously exposed to cobalt and tungsten carbide (odds ratio (OR)=1.93, 95% CI 1.03-3.62) adjusted for other cobalt exposure (OR=2.21, 95% CI 0.99-4.90). The odds ratios increased with cumulative exposure (first quartile, OR=1.00; second quartile, OR=2.64; third quartile, OR=2.59; fourth quartile, OR=4.13) and, to a lesser degree, with duration of exposure (one decade, OR=1.00; two decades, OR=1.61; three decades, OR=2.77; four decades, OR=2.03). Adjustments for smoking and for exposures to known or suspected carcinogens did not change the results, yet the odds ratio for smoking (3.38) was lower than expected, suggesting the possibility of some misclassification. Occupational risk was highest among smokers. This study supports the hypothesis that workers who manufacture hard metals have an increased mortality from lung cancer due to simultaneous exposure to cobalt and tungsten carbide.

A job exposure matrix (JEM) was developed by a committee of experts using the DELPHI method, in the French hard metal industry, in order to assess occupational exposures to cobalt along with tungsten carbide resulting from the industrial process. This JEM is part of a nested case-control study, carried out within the historical cohort of workers ever employed in these factories, aimed at assessing lung cancer risk. The committee included 8 experts: hygienists, chemical engineers, occupational physicians and epidemiologists. The JEM was developed in four stages: (i) visit of factories, (ii) definition of lines (job-periods) and columns (exposures) of the JEM, (iii) definition of coding procedures, (iv) coding the cells of the JEM. This last stage used a method derived from the DELPHI method. Throughout the study period 1945-1994. 320 job-periods and 21 agents were defined. A quantitative assignment (level 0 to level 9) along with a frequency code (1 to 3) was attempted for 4 agents, whereas only a qualitative assignment (non exposed/exposed, i.e. 0/l) was done for the other agents. An additional probability code (1 to 3) was assigned to all agents. This procedure led to 46 columns and 14,720 cells in the JEM. When applying the DELPHI method, the consensus of the committee was obtained for 85% of all cells after the first individual assignment of experts, 88% after the second individual assignment and 100% after the third assignment by the experts all together. In order to validate the JEM, these expert assignments will be brought together with the results of exposure measurements that were performed in some workplaces of these factories. The JEM will also be linked with the data base of the case-control study for the exposure assessment of cases and controls.

Objectives: To assess the effect of an occupational exposure to talc dust on respiratory health., Methods: 166 talc millers from a French factory underwent spirometry and filled in a standardised respiratory questionnaire during their annual medical visit in 1989. A full sized chest radiograph taken in 1987 for the subjects hired before 1982 was also available, for the others a radiograph taken when hired was used. Radiography was repeated in 1992 for all subjects still active at this date (n = 139). The occupational exposure to talc dust was characterised for each workplace with 1440 personal samples collected since 1986 and by semiquantitative estimates of the historical exposure., Results: The geometric mean (range) of estimated exposure was 1.87 (0.5 to 50) mg/m3 and the estimated cumulative exposure at the date of spirometry was > 150 y mg/m3 for 41 subjects. After adjustment for smoking in a linear model the standardised residual values of both forced vital capacity and forced expiratory volume in one second decreased significantly with increasing exposure. The prevalence of dyspnoea also increased after adjustment for smoking categories and age in a logistic regression. The prevalence of small radiological opacities was significantly related to age and to the exposure after adjustment for age and smoking categories. The incidence of new opacities between the two radiographs (11 new opacities with a profusion higher than 0/1) was significantly related to smoking (10 out of 11 are smokers) but not to the exposure., Conclusion: This study shows an effect of high levels of talc dust both on functional variables and on the prevalence of small radiological images, but provides no clear evidence about the possible effect of present levels of exposure.

We assessed mortality rates in a cohort of French potash miners between 1977 and 1987. The cohort comprised all workers of a potash mine active on January 1, 1977, or subsequently hired, with at least 3 years of employment. We compared the mortality of the subcohort exposed to heat from underground work (U) with the mortality of those who had never worked underground (D). The overall mortality was low [standardized mortality ratio (SMR) = 0.89, based on 570 deaths] and was lower among underground workers (age-standardized mortality rate = 660 per 100,000 person-years, 266 deaths) than among daylight workers (age-standardized mortality rate = 710 per 100,000 person-years, 304 deaths). Mortality from ischemic heart diseases (IHD) was higher for underground workers than for daylight workers (relative risk = 1.6). As exposure to heat decreased over time, we analyzed the mortality according to period of hire: within underground workers, we observed a downward trend for mortality from IHD which contrasted with a stable mortality from IHD among daylight workers. Among subjects who left for medical reasons, IHD mortality was five times greater in the heat-exposed group compared with daylight workers. The data are consistent with an increased risk of ischemic heart diseases from a hot environment that is offset by a strong healthy worker effect.

In a follow-up study of 294 men who had worked for at least 6 months in a chromate-producing factory in France between 1958 and 1987, only 16 were lost to follow-up and the number of person-years in the study was 5207. Occupational data were provided by the administration of the plant. The causes of deaths were ascertained from hospital and general practitioners' records. The observed numbers of deaths were compared with the expected numbers based on local rates with adjustment for age, sex and calendar time (standardized mortality ratio, SMR). The overall mortality did not differ significantly from that expected (SMR = 1.20, 95% CI = 0.98-1.47), whereas mortality due to lung cancer was in significant excess (SMR = 3.60, 95% CI = 2.13-5.68). Significantly higher lung cancer SMRs were found for workers whose duration of employment was more than 10 years. A non-significant excess was observed for all forms of digestive tract cancer (SMR = 1.30, 95% CI = 0.60-2.47). There were two cases of brain cancer when 0.24 was expected (SMR = 8.44, 95% CI = 1.02-30.49). No previous report has mentioned an association of brain cancer with chromate pigments; however, because of the small numbers involved, a chance excess should be considered.

Wheat flour is a complex organic dust likely to induce immune responses when inhaled in work environment conditions. We compared the humoral status of 159 exposed workers from 11 flour mills and one industrial bakery with that of 41 workers from a salt factory. IgG, IgA, and IgM levels of antibodies to whole flour and to gliadin were assayed using ELISA tests in serum and saliva samples. Serum levels of IgG and IgA to both antigens were significantly higher (p < 0.0001) in occupationally exposed workers. Exposed workers had significantly higher levels of salivary IgG (p = 0.005) and IgA (p < 0.0001) to whole flour and of salivary IgG (p = 0.0005) to gliadin. In both groups, similar levels of anti-gliadin salivary IgA antibodies were observed. These data suggest that occupational exposure to wheat flour triggers specific immune responses, most likely through stimulation of the mucosal immune system. The presence of significant levels of serum antibodies, however, indicates that a systemic immunologic response is also present among exposed individuals.

A historical mortality study of a cohort of employees of a gold mining and refining company was carried out in Salsigne, France. A major goal of the study was to investigate the relationship between lung cancer mortality and exposure to arsenic, radon, silica, and other contaminants of the working environment. A twofold excess of lung cancer was found both among miners and smelters, mainly concentrated among workers who had experienced exposure to past levels of arsenic, radon, and silica. The consistency of the results in the mine and the refinery are suggestive of a carcinogenic risk from both soluble and insoluble arsenic, although the potential role of other factors cannot be dismissed.

The mortality pattern of workers involved in the production of stainless steel (SS) was studied from 1968 to 1984 in order to investigate a possible risk of lung cancer in relation to exposure to chromium compounds, polycyclic aromatic hydrocarbons, and silica. The role of heat exposure in mortality from cardiovascular diseases also was examined. The cohort was comprised of 4,227 workers. Complete individual job histories were provided by the company (UGINE SA). The smoking habits of 24 percent of the cohort members were known from the interview of workers still active during the data collection. The observed numbers of deaths were compared with the expected ones based on national rates with adjustment for age, sex, and calendar time (standardized mortality ratio, SMR). No significant excesses of lung cancer were observed among workers employed in the manufacture of ferroalloys (SMR = 0.68) and in the melting and casting of SS (SMR = 1.04), whereas a significant excess appeared among SS foundry workers (SMR = 2.29). This excess was higher and remained significant among workers with more than 30 years since first employment in the foundry area (SMR = 3.34). Among subjects exposed to heat, no excess was observed for all cardiovascular diseases or for ischemic heart diseases.

The follow-up of a cohort of workers employed in an electrochemical plant producing cobalt and sodium, previously studied from 1950-1980, has been extended from 1981-1988. The standardized mortality ratio (SMR) for all causes of death was 0.85 (95% confidence interval [CI] = 0.76-0.95, 309 observed) for the whole cohort, and 0.95 (95% CI = 0.83-1.08, 247 observed) for the subcohort of workers born in France. With regard to lung cancer mortality among cobalt production workers, which is the main objective of the study, the SMRs were, respectively, 0.85 (95% CI = 0.18-2.50, 3 observed) and 1.16 (95% CI = 0.24-3.40, 3 observed). Neither did any excess of mortality from diseases of the circulatory and of the respiratory systems appear among cobalt production workers. Maintenance workers, however, exhibited high SMRs for lung cancer, reaching statistical significance for duration of exposure and time since first exposure > or 30 years. This study does not support the hypothesis of a relationship between lung cancer and cobalt exposure.

A previous study on 536 retired coke oven plant workers in Lorraine Collieries (France) reported an excess of deaths from lung cancer (standardised mortality ratio (SMR) = 251) compared with the French male population. Occupational exposures during working life were retraced for each subject, but the number of deaths during the observation period (1963-82) was small, and smoking habits were known only for dead subjects. In 1988, the cohort was re-examined (182 deaths occurred between 1963 and 1987) and smoking habits were determined for all the subjects. This study confirmed the excess of lung cancer (SMR = 238, p < 0.001). It showed an excess of mortality from all causes (SMR = 141, p < 0.001), overall cancers (SMR = 133, p < 0.05), and cardiovascular diseases (SMR = 133, p < 0.05). A significant excess of deaths was found for subjects who worked near the ovens for all causes (145, p < 0.01), lung cancer (SMR = 252, p < 0.01), colon cancer (SMR = 381, p < 0.05), and cardiovascular diseases (SMR = 155, p < 0.05). A significant excess mortality was also found from all causes (176, p < 0.05) and stomach cancer (SMR = 538, p < 0.01) in subjects who worked in byproducts, from lung cancer (SMR = 433, p < 0.001) in those in the workshops, and from cirrhosis of the liver and alcoholism (SMR = 360, p < 0.01) in those underground; but, due to small numbers, these figures were not robust. An excess of mortality from all causes (SMR = 163, p<001), lung cancer (SMR = 228, p<0.05) and cardiovascular diseases (SMR = 179, p<0.01) was shown also for non-exposed or slightly exposed subjects. The fact that, on the whole, mortality of various exposed groups was similar to that of non-exposed or slightly exposed workers may be explained in part by the selection at hiring and the healthy worker effect. As an increased risk of lung cancer was noted among subjects who worked in the old generations of plant compared with the other workers (although the relative risk was not significant) it is concluded that the role of occupational hazards could not be excluded.

Lung function was studied in 354 coke oven plant workers in the Lorraine collieries (Houillères du Bassin de Lorraine, France) who retired between 1963 and 1982 and were still alive on 1 January 1988. A spirometric examination was performed on 68.4% of them in the occupational health service. Occupational exposure to respiratory hazards throughout their career was retraced for each subject. No adverse effect of occupational exposure on ventilatory function was found. Ventilatory function was, however negatively linked with smoking and with the presence of a respiratory symptom or discrete abnormalities visible on pulmonary x ray films. The functional values were mostly slightly lower than predicted values and the most reduced index was the mean expiratory flow, FEF25-75%. The decrease in forced expiratory volume in one second (FEV1) was often parallel to that in forced vital capacity (FVC), but it was more pronounced for subjects who had worked underground, for smokers of more than 30 pack-years, and for subjects having a respiratory symptom. Pulmonary function indices were probably overestimated because of the exclusion of deceased subjects and the bias of the participants.

The effect of past occupational exposure on morbidity was studied in 354 coke oven workers in Lorraine Collieries (France) who retired between 1963 and 1982, and were still alive in 1988; 96% of them participated in this study. Occupational exposure to respiratory hazards during the working life was retraced for each subject. No significant association between the occupational exposure and the frequency of ischemic cardiopathies, arterial hypertension, gastro-duodenal ulcers, and respiratory symptoms was revealed. However, subjects who had worked on the Ovens, in the Workshops, and in the Byproducts showed a prevalence of arterial hypertension significantly higher than the non- or slightly exposed subjects. The healthy worker effect phenomenon, the exclusion of deceased subjects, and the small size of this retiree population may conceal possible differences between exposure groups.

Objective: After an inquiry from the employees of an offset printing plant, a historical cohort study was conducted to investigate cancer mortality among these workers.Methods: The cohort comprised 262 men, who contributed 2771 person-years of observation. 16 deaths were identified during the follow up period (1980-91). Expected numbers of deaths were derived from age specific regional rates. Standardised mortality ratios (SMR) and 95% confidence intervals (95% CIs) were calculated.Results: An increased cancer mortality was found after 10 years of employment (SMR 213, 95% CI 98 to 405, based on nine deaths), mainly due to a high mortality from lung cancer (SMR 381, 95% CI 104 to 975, four deaths), and from oesophageal cancer (SMR 1049, 95% CI 216 to 3065, three deaths). For workers with at least 20 years since the start of employment, the SMR was 262 (95% CI 105 to 540) for all cancer sites, 447 (95% CI 92 to 1306) for lung cancer, and 1094 (95% CI 132 to 3952) for oesophageal cancer. The increased cancer mortality was concentrated among pressmen.Conclusion: Although based on small numbers, the findings suggest an increased risk of cancer among these workers, which should be further investigated. [ABSTRACT FROM AUTHOR]