An investigation of systematic changes in occupational exposure.

Nonstationary behavior in occupational exposure was examined among a number of job groups from different industries. A change in the mean level of exposure between two survey periods was evaluated by applying mixed-effects models. Overall, differences between surveys were observed in slightly more than one-third of the industries analyzed and in about one-quarter of the total number of comparisons performed.

Modeling long-term average exposure in occupational exposure-response analysis.

Objectives: Estimates of long-term average exposure to occupational hazards are often imprecise because intraindividual variability in exposure can be large and exposure is usually based on one or few measurements. One potential result is bias of exposure-response relationships. The possibility was studied of a more valid measure of exposure being obtained by modeling exposure and consequently increasing the number of days with exposure estimates, using simple measurable exposure surrogates.

Determinants of dust and endotoxin exposure of pig farmers: development of a control strategy using empirical modelling.

Personal exposure to dust and endotoxin was measured among 198 Dutch pig farmers. For each participant 8-h measurements were made on 2 days, one in summer 1991 and one in winter 1992. Mean time-weighted average (TWA) exposure to dust was 3.

Urinary excretion of tetrahydrophtalimide in fruit growers with dermal exposure to captan.

The relation between dermal and respiratory exposure and uptake into the body of captan, measured as 24 hr cumulative tetrahydrophtalimide (THPI) dose, was studied among 14 male fruit growers applying pesticides in orchards in the Netherlands. No contribution of respiratory exposure was observed on THPI in the urine. Dermal exposure, measured with skin pads, showed a clear relation with THPI in urine when exposure was estimated from exposure on skin pads of ankles and neck.

Cancer risk for European asphalt workers.

Objectives: The feasibility of a European epidemiologic study of cancer risk among asphalt workers was examined in Western Europe. The study was motivated by occupational and public health concern about possible health risk from exposure to bitumen fumes.

Methods: Information on the accessibility and quality of epidemiologic resources, retrospective worker records, mortality and cancer incidence records, and exposures was requested from research institutes and road paving and asphalt mixing companies in 15 European countries.

Wood-dust exposure during wood-working processes.

Personal and ambient full shift concentrations of inhalable wood dust were measured at different wood-working processes in two joineries and a furniture factory in The Netherlands. The current occupational exposure limit for wood dust is still 5 mg m-3 total dust, but the Dutch Expert Committee for Occupational Standards has recently recommended a health-based limit of 0.2 mg m-3 (total wood dust).

Assessment and grouping of occupational magnetic field exposure in five electric utility companies.

Objectives: Occupational exposure to 60-Hz magnetic fields was surveyed among randomly selected workers in five electric power companies.

Methods: The study facilitated the examination of exposure variability and provided the base for a job-exposure matrix linking health outcomes and occupational magnetic field exposures.

Results: Average exposures ranged from 0.

Occupational epidemiology in the rubber industry: implications of exposure variability.

The variability of exposure has important implications for the design of occupational epidemiologic studies. To assess the influence of this variability in the rubber industry, the efficiency of different schemes for classification of exposure to particulates, cyclohexane-soluble contaminants, and solvents was assessed. Groupings based on job title, plant, factors affecting exposure, published classifications, and the International Standard Classification of Occupations of the International Labor Organization (ISCO-ILO) were compared.

Organization and classification of work history data in industry-wide studies: an application to the electric power industry.

Industry-based cohort studies require systems for organizing work history data. Although the ultimate goal may be to assess the hazards of specific exposures, classification of the job titles that comprise work histories serves an important descriptive purpose in itself and is often necessary before exposure data can be obtained. A system we have created for organizing jobs in a study of 135,000 workers at five electric power companies highlights conceptual and practical issues in managing work history data for epidemiological studies.

Occupational exposures estimated by a population specific job exposure matrix and 25 year incidence rate of chronic nonspecific lung disease (CNSLD): the Zutphen Study.

The influence of occupational exposures on total mortality and respiratory mortality and morbidity was examined, employing a population specific Job Exposure Matrix (JEM). Moreover, the relationship between time-related variables of exposure to dust and chronic nonspecific lung disease (CNSLD) incidence was analysed, using time since first exposure and duration of exposure. Occupational exposures in the Zutphen cohort were assessed by application of a JEM, arbitrarily considering jobs as exposed when at least 10% of men who had held the job of interest reported an exposure to one or more from a list of 27 chemical agents.

Empirical modelling of chemical exposure in the rubber-manufacturing industry.

As part of a study of working conditions chemical exposure was assessed in 10 rubber-manufacturing plants in The Netherlands. Personal exposures to airborne particulates, rubber fumes and solvents, and also dermal contamination, were measured. To identify factors affecting exposure the personal exposure levels and information on tasks performed, ventilation characteristics and production variables were used in multiple linear regression models.

Variation of exposure between workers in homogeneous exposure groups.

It is generally assumed that workers employed in the same job at a given location are uniformly exposed, i.e., that they have the same long-term mean exposure.

A comprehensive evaluation of within- and between-worker components of occupational exposure to chemical agents.

A database of approximately 20,000 chemical exposures has been constructed in close co-operation between the School of Public Health of the University of North Carolina at Chapel Hill and the Department of Air Pollution of the Wageningen Agricultural University. A special feature of this database is that only multiple measurements of exposure from the same workers were included. This enabled estimation of within- and between-worker variance components of occupational exposure to chemical agents throughout industry.

The relationship between polycyclic aromatic hydrocarbons in air and in urine of workers in a Söderberg potroom.

The relationships between increase of urinary 1-hydroxypyrene over the workweek and the airborne concentrations of benzo(a)pyrene and coal tar pitch volatiles (CTPVs) were studied among groups of workers in a vertical-stud Söderberg potroom of an aluminum smelter. There was a strong correlation between the natural logarithm of the pyrene concentration and the natural logarithm of the total polycyclic aromatic hydrocarbon (PAHs) concentration in personal air samples (r = 0.94).

Prevention and control of chemical exposures in the rubber manufacturing industry in The Netherlands.

In a survey in the rubber manufacturing industry in The Netherlands both the chemical and physical exposure of operators as well as company policies on working conditions were assessed. Defining the effectiveness of control measures was a part of this study and is the subject of this article. A method of solution-directed workplace analysis was applied to compare and evaluate the control measures within this branch of industry.

Job exposure matrices in industry.

Job exposure matrices (JEM) are designed to link information on occupation with information on exposure to specific workplace hazards. In spite of some limitations, JEM are particularly useful in large retrospective epidemiological studies. The development of JEM designed for a company or an industrial sector have a more specific field of application than JEM used in population-based studies, and can therefore be based on a more detailed classification of occupations and better exposure information.

Performance of two general job-exposure matrices in a study of lung cancer morbidity in the Zutphen cohort.

Data from a general population cohort of 878 men from the town of Zutphen, The Netherlands, were used to evaluate the performance of two general job-exposure matrices. Exposures generated by the job-exposure matrices on the basis of job histories were compared. The validity of those exposures was measured against exposures reported by the participants in 1977/1978.

Relations between occupation, smoking, lung function, and incidence and mortality of chronic non-specific lung disease: the Zutphen Study.

Information gathered in the "Zutphen study", the Dutch contribution to the Seven Countries Study was used for the present study. Follow up data from 1965 to 1 July 1985 were used. During this follow up, the morbidity state of the participants was verified at regular intervals.

Occupational exposure and 25-year incidence rate of non-specific lung disease: the Zutphen Study.

Information gathered in the Zutphen Study, the Dutch contribution to the Seven Countries Study that started in the 1960s, was used for the present study. In 1960 878 men participated in the physical examination and they were followed for 25 years until 1 July 1985. During this follow-up, their morbidity status was verified regularly.

Chronic non-specific lung disease and occupational exposures estimated by means of a job exposure matrix: the Zutphen Study.

Information gathered in the Zutphen Study, the Dutch contribution to the Seven Countries Study that started in the 1960s, was used in this study. Of the 1266 men invited to take part in the 1985 survey, 939 (74%) participated. All participants were interviewed according to the BMRC chronic non-specific lung disease (CNSLD) questionnaire and medically examined for CNSLD complaints by a trained physician.

Mutagens in urine of non-smoking and smoking workers in an aircraft tyre retreading plant. Skin exposure as a causal factor?

In an aircraft type retreading plant environmental samples taken at several departments showed mutagenic properties. Thursday urine samples of non-smoking and smoking workers showed higher urinary mutagenicity than urine samples collected on Sundays, thus suggesting occupational exposure to mutagenic substances. A relation between urinary mutagenicity on Thursdays and skin contamination measured on Wednesdays was observed.

Agreement between qualitative exposure estimates and quantitative exposure measurements.

A method for qualitative estimation of the exposure at task level was used and validated with actual measurements in five small factories. The results showed that occupational hygienists were in general the most successful estimators. Plant supervisors and workers handled the estimation method less successfully because of more misclassification of the tasks.