Search

A study to assess the association between the prevalence of hypospadias and maternal occupational exposure to potential endocrine-disrupting chemicals was carried out using data from the congenital anomaly register of the Office for National Statistics. The occupation of the mother is recorded in this register and to facilitate the assessment of maternal occupational exposure, a specific job-exposure matrix for potential endocrine-disrupting chemicals was developed. Seven categories of contaminants were evaluated (pesticides, polychlorinated organic compounds, phthalates, alkylphenolic compounds, bi-phenolic compounds, heavy metals and other substances). Maternal occupations were all coded using the 1980 version of Categories of Occupations. Three occupational hygienists assessed the likelihood of exposure (unlikely, possible, probable) to these seven substance groups for all 348 possible job titles independently. Almost 30% of the job titles were classified as exposed to at least one substance category (possible or probable), with approximately 16% of the job titles being probably exposed to at least one substance category. Some examples of occupations with probable exposure to potential endocrine-disrupting chemicals include: farm workers, electricians, workers in the plastics industry, painters, printers, hairdressers, dental practitioners, laboratory workers, textile workers and cleaners. It is recognized that there are a lot of limitations to the use of job-exposure matrices in general and with the matrix presented in this paper in particular. However, the matrix forms the basis on which further developments on occupational exposure assessment of potential endocrine-disrupting chemicals could be founded. In addition, the job-exposure matrix has identified areas where more exposure information is required. For example, exposure to potential endocrine-disrupting chemicals can occur in occupations such as hairdressing and workers in beauty salons, where the working population is more likely to be female and for which little data exist on levels of exposure.

Objectives Exposure to electromagnetic fields (EMF) has become ubiquitous in modern life and concern has increased regarding possible associated health effects. To date, assessment of occupational exposure has relied on job-exposure matrices, with exposure estimates for very broad occupational categories. To move EMF research forward, a new approach was necessary. A source-based strategy, incorporating detailed information on tasks, equipment used and work organisation could allow a more individualised exposure assessment. Method Information on occupational histories and sources of EMF was collected as part of the INTERPHONE-INTEROCC study, providing an opportunity to assess occupational EMF exposure by assigning exposure to each source used. A source-exposure matrix (SEM) was developed based on measurements identified in the literature and estimates obtained through experts’ elicitation, for sources without available measurements. This paper focuses on the SEM development methodology to ensure the quality and representativeness of the estimates. Results Estimates of exposure for 138 EMF sources were obtained from measurements (1424 aggregated records) extracted from 71 papers and hygiene reports (1974–2013). For each source, exposure was calculated by frequency band and dosimetry type, as the arithmetic and geometric means of all measurements identified. Standard deviations were included in order to characterise the variability of the estimates. Conclusions A source-exposure matrix has been constructed for the most common sources of EMF in the workplace, based on the responses to the INTERPHONE-INTEROCC study questionnaire. This database currently represents the most comprehensive source of information on occupational EMF exposure and is available on request to researchers.

Background Carbon black, a powdered form of elemental carbon is used in the manufacture of rubber products, paints, plastics, and inks. In 1974, the Health and Safety Executive initiated a cohort mortality study on possible carcinogenic effects on carbon black workers. Methods The mortality of a cohort of 1,147 male manual workers from five U.K. factories manufacturing carbon black was investigated for the period 1951–1996. All subjects were employed in the carbon black industry for 12 months or more, and all were first employed before 1975. Limited work histories were used to calculate estimates of individual cumulative exposure to carbon black, using a job-exposure matrix derived by the study team. Results Based on serial rates for the general population of England and Wales, significantly elevated mortality was observed in the main study cohort for all causes (Obs 372, Exp 328.7, SMR 113, P

K vL -Z .0 8 -0 4 .6 3 1 E p Ve rs io n 2 Erik Tielemans1*, Nick Warren2, Thomas Schneider3, Martie van Tongeren4, Martin Tischer5, Peter Ritchie4, Wouter Fransman1, Hans Kromhout6, Jody Schinkel1, Joop van Hemmen1, John Cherrie4 1 TNO Quality of Life, P.O. Box 360, 3700 AJ Zeist, The Netherlands 2 HSL, United Kingdom 3 NRCWE, Denmark 4 IOM, United Kingdom 5 BAuA, Germany 6 IRAS, Utrecht University, The Netherlands

Objectives Currently little is known about risk factors associated with meningioma with the exception of ionising radiation exposure, although there are many suggestions in the literature. As meningioma affects proportionately more females, hormones may play a role. A case control study was undertaken to examine possible associations between specific brain cancers and occupational exposures. We present the analysis of risk of meningioma associated with occupational chemical exposures. Methods The Finnish Job Exposure Matrix (FinJEM) was modified and applied to lifetime work histories of the subjects to obtain occupational exposures to each of 29 agents. Exposures were calculated up to 5 years before the reference date to allow for latency. Case-control analysis examined whether exposure to each agent affected the risk of meningioma, using unconditional logistic regression adjusting for age, sex, country and education. A variety of exposure metrics were investigated including cumulative exposure, ever/never and quintiles of exposure level. Results Information was available on 1925 cases of meningioma and 5813 controls from 7 countries. A high proportion of subjects were determined to be occupationally exposed to PAH and benzo[a]pyrene (∼80%) but no more than 20% of subjects were exposed to the other agents considered. A slight increase in risk of meningioma was found with higher occupational exposures to chromium and nickel (OR=1.2–1.7). Conclusions Exposure to a small number of agents resulted in an elevated risk of meningioma; these suggested links need more detailed examination. Further analyses will include examination of subgroups and of time windows of exposure.

Objectives The aetiology of glioma remains unknown. Occupational exposure to chemicals and other agents have been previously explored as possible risk factors with mixed findings in the literature. This analysis aimed to explore associations between lifetime occupational exposure to selected agents and glioma risk. An adapted version of a Finnish job exposure matrix (FINJEM) was applied to coded occupational histories collected as part of a large, international case-control study. Methods A case-control study was carried out in seven countries with lifetime occupational histories available for 2058 cases and 5813 controls. Occupational exposure estimates to twenty nine agents categorised into five broad groups (dust (n=4), solvents (n=11), metals (n=5), combustions products (n=6) and others (n=3)) were applied to all occupations held per individual. Statistical analysis was carried out using unconditional logistic regression, stratified by age, sex and study centre. Several indices of exposure were investigated (ever/never, quintiles, cumulative exposure) and analyses were repeated by sex. Results Estimated exposure to any of the chemical agents included in INTEROCC was over 80% for benzo(a)pyrene and polycyclic aromatic hydrocarbons due to environmental tobacco smoke exposure. For other exposures percentages varied between 0.7% (sulphur dioxide) and 18% (asbestos) for control participants. No significant relationship with glioma risk was found between estimated occupational exposures for any of the chemical agents considered. Conclusions Lifetime occupational exposure to the chemicals explored was not found to be associated with risk of glioma. Additional analyses relating to time windows of exposure and grouping exposures will also be carried out.

Objectives In case-control studies exposure is generally inferred from self-reported job histories coded to occupation and industry classifications. In the INTEROCC study, a hygienist from each of seven countries coded local jobs reported (39 613 total jobs) to assign chemical and extremely low frequency (ELF) exposures through linkage with two job-exposure matrices. To maximise the quality and comparability of coding between countries, two comparison trials were conducted. Methods After establishing guidelines for coding, and a group training exercise, a first trial assessed coding on 50 randomly selected subjects (241 jobs) and differences were evaluated and discussed. A second trial of 50 jobs was completed after coding finished. Pair-wise agreement between each coder was assessed, and an analysis of variance (ANOVA) was used to evaluate comparability of exposures assigned to selected chemical agents and ELF. Results Pair wise agreements between coders for ISCO 68 and ISCO 88 showed improvement of at least 10% between trials. Although differences were observed in the numbers of jobs assigned with exposure to the chemical agents and ELF, and in the mean cumulative exposure estimated for given agents, none were significant in either trial. Conclusions Exposure misclassification in occupational epidemiology has the potential to bias results and complicate interpretations. This study showed that the reliability of occupational coding could be improved by providing clear guidelines and using a web forum to discuss difficult cases. The remaining variability may reflect true inter-country differences; however, the difference in coding did not result in significant differences in exposure assignment.

Objectives The INTEROCC project is a multi-centre case-control study which aims to examine occupational exposures to chemical agents and EMF and risk of brain cancer. The Finnish Job Exposure Matrix (FINJEM) was identified as the most appropriate job exposure matrix. However, a number of modifications were applied to FINJEM resulting in the development of the INTEROCC FINJEM. Methods The following refinements were included in the INTEROCC FINJEM. 1) Development of a cross-walk between the Finnish occupational code and ISCO-68 codes. For ISCO codes that were linked to multiple Finnish codes, weighted means of the exposure estimates were calculated. Exposure was refined for codes with heterogeneous exposure according to Canadian exposure data. Coding/exposure issues were addressed, for example, supervisors and petrol station attendant. 2) Splitting of 1960–1984 into two time periods (1960–1974 and 1975–1984). 3) Improving internal consistency of hydrocarbon exposures. 4) Increasing benzene exposure estimates pre-1974. 5) Improving diesel and gasoline exhaust fume exposure assessment. 6) Including exposure to PAH and B[a]P from environmental tobacco smoke exposure. Results The modifications generally resulted in an increase in the number of INTEROCC subjects that were considered to be exposed to chemical agents. When assigning subjects to cumulative exposure groups, the cumulative exposure level for the highest exposure group increased for most of the agents. Conclusions The cross-walk ensured that the FINJEM exposure estimates could be applied to the INTEROCC study subjects. The modifications applied in developing the INTEROCC FINJEM improved the exposure estimates for this international study, based on peer review.

The very rapid worldwide increase in mobile phone use in the last decade has generated considerable interest in the possible health effects of exposure to radio frequency (RF) fields. A multinational case-control study, INTERPHONE, was set-up to investigate whether mobile phone use increases the risk of cancer and, more specifically, whether the RF fields emitted by mobile phones are carcinogenic. The study focused on tumours arising in the tissues most exposed to RF fields from mobile phones: glioma, meningioma, acoustic neurinoma and parotid gland tumours. In addition to a detailed history of mobile phone use, information was collected on a number of known and potential risk factors for these tumours. The study was conducted in 13 countries. Australia, Canada, Denmark, Finland, France, Germany, Israel, Italy, Japan, New Zealand, Norway, Sweden, and the UK using a common core protocol. This paper describes the study design and methods and the main characteristics of the study population. INTERPHONE is the largest case-control study to date investigating risks related to mobile phone use and to other potential risk factors for the tumours of interest and includes 2,765 glioma, 2,425 meningioma, 1,121 acoustic neurinoma, 109 malignant parotid gland tumour cases and 7,658 controls. Particular attention was paid to estimating the amount and direction of potential recall and participation biases and their impact on the study results.

The UK regulatory methods currently used for estimating residents' potential pesticide exposure were assessed to determine whether they provide sufficiently conservative estimates. A non-random sample of 149 residents living within 100 m of fields where pesticides were sprayed provided first morning void urine samples one and/or two days after spraying. Using farmers’ spray information, regulatory exposure assessment (REA) models were applied to estimate potential pesticide intake among residents, with a toxicokinetic (TK) model used to estimate urinary biomarker concentrations in the mornings of the two days following the spray. These were compared with actual measured urinary biomarker concentrations obtained following the spray applications. The study focused on five pesticides (cypermethrin, penconazole, captan, chlorpyrifos and chlormequat). All measured cypermethrin urinary biomarker levels were lower than the REA-predicted concentrations. Over 98% and 97% of the measured urinary biomarker concentrations for penconazole and captan respectively were lower than the REA-predicted exposures. Although a number of the chlorpyrifos and chlormequat spray-related urinary biomarker concentrations were greater than the predictions, investigation of the background urinary biomarker concentrations suggests these were not significantly different from the levels expected had no pesticide spraying occurred. The majority of measured concentrations being well below the REA-predicted concentrations indicate that, in these cases, the REA is sufficiently conservative.

Background The evaluation of smoke-free legislation (SFL) in the UK examined the impacts on exposure to second-hand smoke, workers’ attitudes and changes in respiratory health. Studies that investigate changes in the health of groups of people often use self-reported symptoms. Due to the subjective nature it is of interest to determine whether workers’ attitudes towards the change in their working conditions may be linked to the change in health they report. Methods Bar workers were recruited before the introduction of the SFL in Scotland and England with the aim of investigating their changes to health, attitudes and exposure as a result of the SFL. They were asked about their attitudes towards SFL and the presence of respiratory and sensory symptoms both before SFL and one year later. Here we examine the possibility of a relationship between initial attitudes and changes in reported symptoms, through the use of regression analyses. Results There was no difference in the initial attitudes towards SFL between those working in Scotland and England. Bar workers who were educated to a higher level tended to be more positive towards SFL. Attitude towards SFL was not found to be related to change in reported symptoms for bar workers in England (Respiratory, p = 0.755; Sensory, p = 0.910). In Scotland there was suggestion of a relationship with reporting of respiratory symptoms (p = 0.042), where those who were initially more negative to SFL experienced a greater improvement in self-reported health. Conclusions There was no evidence that workers who were more positive towards SFL reported greater improvements in respiratory and sensory symptoms. This may not be the case in all interventions and we recommend examining subjects’ attitudes towards the proposed intervention when evaluating possible health benefits using self-reported methods.

Background In epidemiological studies, it is often not possible to measure accurately exposures of participants even if their response variable can be measured without error. When there are several groups of subjects, occupational epidemiologists employ group-based strategy (GBS) for exposure assessment to reduce bias due to measurement errors: individuals of a group/job within study sample are assigned commonly to the sample mean of exposure measurements from their group in evaluating the effect of exposure on the response. Therefore, exposure is estimated on an ecological level while health outcomes are ascertained for each subject. Such study design leads to negligible bias in risk estimates when group means are estimated from ‘large’ samples. However, in many cases, only a small number of observations are available to estimate the group means, and this causes bias in the observed exposure-disease association. Also, the analysis in a semi-ecological design may involve exposure data with the majority missing and the rest observed with measurement errors and complete response data collected with ascertainment. Methods In workplaces groups/jobs are naturally ordered and this could be incorporated in estimation procedure by constrained estimation methods together with the expectation and maximization (EM) algorithms for regression models having measurement error and missing values. Four methods were compared by a simulation study: naive complete-case analysis, GBS, the constrained GBS (CGBS), and the constrained expectation and maximization (CEM). We illustrated the methods in the analysis of decline in lung function due to exposures to carbon black. Results Naive and GBS approaches were shown to be inadequate when the number of exposure measurements is too small to accurately estimate group means. The CEM method appears to be best among them when within each exposure group at least a ’moderate’ number of individuals have their exposures observed with error. However, compared with CEM, CGBS is easier to implement and has more desirable bias-reducing properties in the presence of substantial proportions of missing exposure data. Conclusion The CGBS approach could be useful for estimating exposure-disease association in semi-ecological studies when the true group means are ordered and the number of measured exposures in each group is small. These findings have important implication for cost-effective design of semi-ecological studies because they enable investigators to more reliably estimate exposure-disease associations with smaller exposure measurement campaign than with the analytical methods that were historically employed.

A large study to investigate the respiratory health effects of occupational exposure to carbon black in the European carbon black manufacturing industry commenced in 1987. During the study, a large amount of personal occupational exposure data was collected. This article describes the empirical models used to study the determinants of inhalable dust exposure, using data from 16 factories collected in the third and last cross-sectional phase of this study. Information on activities during the measurements was collected using short job category-specific questionnaires. In addition, questionnaires were completed by factory representatives on the implementation of control measures and changes in production process since the first cross-sectional phase. Mixed effects analyses of variance models were used to identify determinants of exposure, while taking into account the within- and between-worker (random) variance components. The results of these models show that, for any job category, factory is a strong predictor of exposure in this industry. These differences could not be explained entirely by factors such as age of the factory or the control measures implemented since the first phase of the study. Surprisingly, implementation of local exhaust ventilation systems had an effect that was counterintuitive; for example, in warehouses where local exhaust ventilation systems had been implemented, higher dust exposure levels were found compared to those where such control measures had not been installed since the first cross-sectional survey. Season appeared to have some effect on exposure for some job titles, with generally relatively low exposures being found in the summer. Finally, a number of activities were identified that caused higher levels of dust exposure, most notably "changing of filters" and "clean-up of carbon black spills".

For the exposure assessment in the 2010 REACH dossiers of petroleum substances, Concawe has used the Tier 1 exposure model ECETOC TRA v.2. To account for the heavier, less volatile and more complex petroleum substances and the corresponding exposure situations, several modifications not originally within the scope of the ECETOC TRA were developed, including an approach to estimate liquid aerosol along with some risk management measures describing the use and handling of petroleum substances commonly in use in the European oil refining industry. In this project, Chemical Safety Assessments (CSA) on these petroleum substances were evaluated concerning relevant industry areas and included scenarios. The comparison exercise showed some discrepancies depending on substance group and the specific scenarios, which could be partly attributed to new modifiers or other changes of the ECETOC standard algorithm. Concerning aerosol exposure, no significant underestimations were found for the evaluated scenario in case of other lubricant base oils while in the case of heavy fuel oils (HFO), results were inconclusive. Overall, it is recognized that available sampling methods for liquid aerosol often tend to give biased or at least variable exposure results and this has to be considered for future investigations concerning risk assessment of petroleum substances or validation of the existing CSA. Measurements made for HFO showed higher overall and vapor concentrations compared to the aerosol values, suggesting that either vapor may be more relevant than previously assumed for high boiling petroleum substances or the corresponding aerosol measurements may not be suitable for a comparison with Derived No Effect Levels or model estimates. A qualitative evaluation of the updates made when changing from ECETOC TRA v.2 to v.3 suggested that inhalation exposure estimates will probably be lower if the more recent version is used due to newly introduced or changed measures or operational conditions and partly due to modified initial exposure estimates.