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Background: Several toxicologic and epidemiologic studies have produced evidence that occupational exposure to polycyclic aromatic hydrocarbons (PAH) is a risk factor for ischemic heart disease (IHD). However, a clear exposure-response relation has not been demonstrated., Methods: We studied a relation between exposure to PAH and mortality from IHD (418 cases) in a cohort of 12,367 male asphalt workers from Denmark, Finland, France, Germany, Israel, The Netherlands and Norway. The earliest follow up (country-specific) started in 1953 and the latest ended in 2000, averaging 17 years. Exposures to benzo(a)pyrene were assessed quantitatively using measurement-driven exposure models. Exposure to coal tar was assessed in a semiquantitative manner on the basis of information supplied by company representatives. We carried out sensitivity analyses to assess potential confounding by tobacco smoking., Results: Both cumulative and average exposure indices for benzo(a)pyrene were positively associated with mortality from IHD. The highest relative risk for fatal IHD was observed for average benzo(a)pyrene exposures of 273 ng/m or higher, for which the relative risk was 1.64 (95% confidence interval=1.13-2.38). Similar results were obtained for coal tar exposure. Sensitivity analysis indicated that even in a realistic scenario of confounding by smoking, we would observe approximately 20% to 40% excess risk in IHD in the highest PAH-exposure categories., Conclusions: Our results lend support to the hypothesis that occupational PAH exposure causes fatal IHD and demonstrate a consistent exposure-response relation for this association.

Objectives: The aim of the study was to investigate cancer risk following employment in the asphalt industry., Methods: Cancer incidence was studied among 22 362 male asphalt workers employed for more than one season in jobs entailing exposure to bitumen (mainly road pavers) in Denmark, Finland, Norway, and Sweden. These workers are part of a European cohort of asphalt workers, for which results on mortality have been reported. The follow-up was almost complete, and reference rates were obtained from national cancer registries., Results: The incidence of cancer was reduced in all four countries [overall standardized incidence ratio (SIR) 0.89, 95% confidence interval (95% CI) 0.86-0.94]. Lung cancer incidence was increased in all four countries, yielding an overall SIR of 1.21 (95% CI 1.07-1.36), but no trend was detected according to time since first employment. No overall increased incidence of bladder cancer was observed, but there was a suggestion of a tendency towards higher risk with longer time since first employment, with a relative risk of 1.85 (95% CI 0.90-3.78) for more than 30 years versus 1-14 years (P-value for trend 0.1). The incidence of lip and stomach cancer was nonsignificantly increased, and the excess was present mainly in Denmark. No increased incidence was detected for other neoplasms, notably malignant melanoma, nonmelanoma skin cancer, and kidney cancer., Conclusions: The results of this study confirm the pattern of cancer risk detected in the mortality analysis of the European cohort; in addition, they provide suggestive evidence of an excess risk of bladder cancer among asphalt workers.

Work in the asphalt industry has been associated with nonmalignant respiratory morbidity and mortality, but the evidence is not consistent. A historical cohort of asphalt workers included 58,862 men (911,209 person-years) first employed between 1913 and 1999 in companies applying and mixing asphalt in Denmark, Finland, France, Germany, Israel, the Netherlands, and Norway. The relations between mortality from nonmalignant respiratory diseases (including the obstructive lung diseases: chronic bronchitis, emphysema, and asthma) and specific chemical agents and mixtures were evaluated using a study-specific exposure matrix. Mortality from obstructive lung diseases was associated with the estimated cumulative and average exposures to polycyclic aromatic hydrocarbons and coal tar (p values of the test for linear trend = 0.06 and 0.01, respectively). The positive association between bitumen fume exposure and mortality from obstructive lung diseases was weak and not statistically significant; confounding by simultaneous exposure to coal tar could not be excluded. The authors lacked data on smoking and full occupational histories. In conclusion, exposures to polycyclic aromatic hydrocarbons, originating from coal tar and possibly from bitumen fume, may have contributed to mortality from obstructive lung diseases among asphalt workers, but confounding and bias cannot be ruled out as an explanation for the observed associations.

Background: An exposure matrix (EM) for known and suspected carcinogens was required for a multicenter international cohort study of cancer risk and bitumen among asphalt workers., Methods: Production characteristics in companies enrolled in the study were ascertained through use of a company questionnaire (CQ). Exposures to coal tar, bitumen fume, organic vapor, polycyclic aromatic hydrocarbons, diesel fume, silica, and asbestos were assessed semi-quantitatively using information from CQs, expert judgment, and statistical models. Exposures of road paving workers to bitumen fume, organic vapor, and benzo(a)pyrene were estimated quantitatively by applying regression models, based on monitoring data, to exposure scenarios identified by the CQs., Results: Exposures estimates were derived for 217 companies enrolled in the cohort, plus the Swedish asphalt paving industry in general. Most companies were engaged in road paving and asphalt mixing, but some also participated in general construction and roofing. Coal tar use was most common in Denmark and The Netherlands, but the practice is now obsolete. Quantitative estimates of exposure to bitumen fume, organic vapor, and benzo(a)pyrene for pavers, and semi-quantitative estimates of exposure to these agents among all subjects were strongly correlated. Semi-quantitative estimates of exposure to bitumen fume and coal tar exposures were only moderately correlated. EM assessed non-monotonic historical decrease in exposures to all agents assessed except silica and diesel exhaust., Conclusions: We produced a data-driven EM using methodology that can be adapted for other multicenter studies., (Copyright 2003 Wiley-Liss, Inc.)

Background: Inhalation of bitumen fumes is potentially carcinogenic to humans., Methods: We conducted a study of 29,820 male workers exposed to bitumen in road paving, asphalt mixing and roofing, 32,245 ground and building construction workers unexposed to bitumen, and 17,757 workers not classifiable as bitumen workers, from Denmark, Finland, France, Germany, Israel, the Netherlands, Norway, and Sweden, with mortality follow-up during 1953-2000. We calculated standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) based on national mortality rates. Poisson regression analyses compared mortality of bitumen workers to that of building or ground construction workers., Results: The overall mortality was below expectation in the total cohort (SMR 0.92, 95% CI 0.90-0.94) and in each group of workers. The SMR of lung cancer was higher among bitumen workers (1.17, 95% CI 1.04-1.30) than among workers in ground and building construction (SMR 1.01, 95% CI 0.89-1.15). In the internal comparison, the relative risk (RR) of lung cancer mortality among bitumen workers was 1.09 (95% CI 0.89-1.34). The results of cancer of the head and neck were similar to those of lung cancer, based on a smaller number of deaths. There was no suggestion of an association between employment in bitumen jobs and other cancers., Conclusions: European workers employed in road paving, asphalt mixing and other jobs entailing exposure to bitumen fume might have experienced a small increase in lung cancer mortality risk, compared to workers in ground and building construction. However, exposure assessment was limited and confounding from exposure to carcinogens in other industries, tobacco smoking, and other lifestyle factors cannot be ruled out., (Copyright 2003 Wiley-Liss, Inc.)

Background: An increased risk of lung cancers among asphalt workers has been suggested in epidemiological studies based on large scale statistical analyses., Methods: In a multi-country study of 29,820 male workers employed in road paving, asphalt mixing and roofing, 32,245 ground and building construction workers and 17,757 other workers from Denmark, Finland, France, Germany, Israel, the Netherlands, Norway, and Sweden, with mortality that was documented from 1953-2000. Exposures to bitumen fume, coal tar, 4-6 ring polycyclic aromatic hydrocarbons, organic vapor, diesel exhaust, asbestos, and silica dust were assessed via a job-exposure matrix. Standardized mortality ratios (SMRs) and 95% confidence intervals (CIs) based on national mortality rates, as well as relative risks (RRs) based on Poisson regression models were calculated., Results: The SMR of lung cancer among workers exposed to bitumen fume (1.08, 95% CI 0.99-1.18) was comparable to that of non-exposed workers (SMR 1.05, 95% CI 0.92-1.19). In a sub-cohort of bitumen-exposed workers without exposure to coal tar, the SMR of lung cancer was 1.23 (95% CI 1.02-1.48). The analysis based on the semi-quantitative, matrix-based exposures in the whole cohort did not suggest an increased lung cancer risk following exposure to bitumen fume. However, in an analysis restricted to road pavers, based on quantitative estimate of bitumen fume exposure, a dose-response was suggested for average level of exposure, applying a 15-year lag, which was marginally reduced after adjustment for co-exposure to coal tar. The results for cancer of the head and neck were similar to those of lung cancer, although they were based on a smaller number of deaths. There was no clear suggestion of an association with bitumen fume for any other neoplasm., Conclusions: The results of the analysis by bitumen fume exposure do not allow us to conclude on the presence or absence of a causal link between exposure to bitumen fume and risk of cancer of the lung and the head and neck., (Copyright 2003 Wiley-Liss, Inc.)

Background: We compared performance of different exposure assessment approaches in a cohort study of cancer risk among European asphalt workers., Methods: Three bitumen fume exposure indices (duration of exposure (years), average exposure (mg/m3) and cumulative exposure (mg/m3*years)) and two latency models (with and without a 15 year lag) were considered for an association between lung cancer mortality and bitumen fume., Results: There was no association between lung cancer risk and either duration or cumulative exposure. However, there was the suggestion of an increase in lung cancer risk accompanying rise in average exposure. Only models with average bitumen fume exposure (with or without lag) improved model fit, albeit to the same extent., Conclusions: Constructing quantitative indices of exposure intensity was justified because they produced the greatest improvement in fit of models that explored possible relationship between bitumen fume exposure and lung cancer risk. The identified associations require further investigation., (Copyright 2003 Wiley-Liss, Inc.)

The ultimate solution in prevention of occupational cancer risks would be to remove carcinogens from the working environment. Elimination of carcinogenic substances can be achieved by replacement of the carcinogen with non-carcinogen(s) having the same functionality, or by using a different process that produces adequate results without the use of carcinogenic agents. This paper presents selected methods and tools, which have been used for substitution purposes in practice. These are: 1. a strategy for substitution, 2. a tool for creating ideas on how to substitute, 3. a software package, SUBTEC, for solving some technical and industrial hygiene problems, and 4. a proposal for a strategy to deal with organizational and psychological barriers encountered when changes are to be introduced.

The aim of this case-referent study was to investigate reproductive hazards other than congenital malformations after exposure to high-frequency electromagnetic radiation. Cases and referents were sampled from a cohort of pregnancies of members of the Union of Danish Physiotherapists through linkage of the union file with national medical registers. Case groups were spontaneous abortions and children with low birth-weight prematurity, and stillbirth/death within one year. Exposure to high-frequency electromagnetic radiation before and during pregnancy was assessed through telephone interviews. As referents to the 270 cases, 316 pregnancies were randomly sampled. A total of 8.4% did not participate. Only 23.5% of the children born by the highly exposed mothers were boys. This value is a statistically significantly altered gender ratio showing a dose-response pattern. High-frequency electromagnetic radiation was furthermore associated with low birthweight, but only for male newborns. The other outcomes were not statistically significantly associated with exposure to high-frequency electromagnetic radiation.

Cancer incidence was studied among 6,144 male foundry workers who were invited to participate in either of two Danish national silicosis surveys conducted during 1967-1969 and 1972-1974. Cancer incidence was followed through to the end of 1985 by computerized linkage to the Danish Cancer Registry, and Standardized Morbidity Ratios (SMRs) were calculated based on incidence rates for the Danish population. For the entire cohort, significantly elevated SMRs were seen for all cancers (SMR, 1.09; 95% CI, 1.01-1.18) and lung cancer (SMR, 1.30; 95% CI, 1.12-1.51), and SMRs were at the borderline of statistical significance for bladder cancer (SMR, 1.24; 95% CI, 0.97-1.59). Excess lung and bladder cancer risk were confined to workers who had worked in foundries for at least 20 y. There was a positive correlation between silicosis prevalence in employees at the foundries at the time of the x-ray examinations and lung cancer incidence during the follow-up period. Squamous cell carcinomas, anaplastic carcinomas, and other lung cancers accounted for the excess lung cancer risk, whereas there was not excess risk among the foundry workers for adenocarcinomas of the lung.

Health surveillance in the work environment involves continuous biological monitoring and medical screening, with the purpose of primary and secondary prophylaxis of work-related diseases. Is this screening activity governed by a rationale based on knowledge of dangerous exposure and the availability of valid tests? In the USA, where health surveillance programmes are used extensively, a study has found screening activity to be associated more with plant size than which relevant exposure. This study was done to elucidate the character and extent of use of health surveillance in the work environment in the EC countries with the aid of a questionnaire survey. The chief medical officers of the National Labour Inspectorates supplied information on substances covered by health surveillance programme in the EC member states, together with the legislative status and numbers of exposed workers. Belgium, France, Italy and the former Federal Republic of Germany made extensive use of health surveillance programmes in cases of known exposure to metals, organic solvents, carcinogenic and genotoxic substances, mineral dust, ionizing radiation, and biological agents. Denmark and Holland ran national programmes only for substances covered by EC directives, while England, Ireland, Spain, and Portugal comprised an intermediate user group. The result suggest that the use of health surveillance is related more to the national choice of standard regulatory instruments than to relevant exposure.

Many patients with occupational diseases fail to obtain compensation because their disease is not recognized as occupational and reported to the authorities. The present study examined the reporting of pleural mesotheliomas and sinonasal adenocarcinomas--cancers with well-known associations with occupational exposures to asbestos and wood dust--in Denmark in 1983-1987. The estimated underreporting was around 50%. Examination of the medical records of patients who had not been reported in 1986-1987 revealed that in most cases the medical records did not contain sufficiently detailed information about occupational exposures. It was recommended that a formal screening interview be carried out whenever a diagnosis is made of a potential occupational cancer. Medical associations may play a major role by issuing guidelines addressing occupational diseases within the fields of their expertise.

This article describes the prophylactic programmes for health surveillance which exist in the occupational environment in Denmark. Compared with other industrialised countries, Denmark has only few established surveillance programmes. Nevertheless, these investigations exist, particularly in the form of non-specific general clinical health investigations at local workplaces, in certain branch agreements and in certain types of work. In addition, the article provides a review of the literature concerning health and health-economic effects of supervision of health. It is concluded that with the existing knowledge, pre-employment examinations and periodic health examinations as routine examinations without and clearly defined object must be regarded as having limited prophylactic value and that examinations of this nature can scarcely give the worker any health benefit or give the employer any economic profit. On the other hand, programmes of this nature may give the employees a false sense of security and contribute towards interpreting of justifiable levels of exposure, on an incorrect basis. Biological monitoring and occupational medical screening include, as a rule, more well directed programmes which will probably be employed to a greater extent in the coming years. Finally, a set of American directives for criteria of utilization, particularly for screening in occupational medicine are discussed. It is maintained here, among other things, the necessity of an integrated analysis of biological monitoring, screening and control of exposure so that health surveillance can be of benefit for all the employees at a workplace and not only the individual worker.