Assessing contact dermatitis risk among Manitoba workers in the Manitoba Occupational Disease Surveillance System.

INTRODUCTION: This exploratory study aimed to assess contact dermatitis (CD) risk among workers using the Manitoba Occupational Disease Surveillance System (MODSS). METHODS: The MODSS linked accepted time-loss claims from the Workers' Compensation Board of Manitoba (2006-2019), with administrative health data from medical and hospital records (1996-2020). CD risk by occupation and industry (hazard ratio, 95% confidence intervals) was estimated using Cox proportional hazard models, adjusted for age and stratified by sex. RESULTS: Increased risk of new onset CD was observed among some occupations and industries with known skin irritants and allergens. Some occupations with known increased risks of CD remained elevated when removing the accepted WCB cases was performed, suggesting that all CD cases in these occupations may not show up in WCB statistics. Increased risk was also observed for occupations and industries with unknown exposures related to CD, whereas some groups known to be at risk of CD were not observed to have elevated risks in this cohort. DISCUSSION: The MODSS successfully identified some occupations and industries known to be at high risk of occupational CD, but not others. Some occupations not typically associated with work-related CD were also identified, which warrants further investigation.

Lifetime excess absolute risk for lung cancer due to exposure to radon: results of the pooled uranium miners cohort study PUMA.

The Pooled Uranium Miners Analysis (PUMA) study is the largest uranium miners cohort with 119,709 miners, 4.3 million person-years at risk and 7754 lung cancer deaths. Excess relative rate (ERR) estimates for lung cancer mortality per unit of cumulative exposure to radon progeny in working level months (WLM) based on the PUMA study have been reported. The ERR/WLM was modified by attained age, time since exposure or age at exposure, and exposure rate. This pattern was found for the full PUMA cohort and the 1960 + sub-cohort, i.e., miners hired in 1960 or later with chronic low radon exposures and exposure rates. The aim of the present paper is to calculate the lifetime excess absolute risk (LEAR) of lung cancer mortality per WLM using the PUMA risk models, as well as risk models derived in previously published smaller uranium miner studies, some of which are included in PUMA. The same methods were applied for all risk models, i.e., relative risk projection up to <95 years of age, an exposure scenario of 2 WLM per year from age 18-64 years, and baseline mortality rates representing a mixed Euro-American-Asian population. Depending upon the choice of model, the estimated LEAR per WLM are 5.38 × 10-4 or 5.57 × 10-4 in the full PUMA cohort and 7.50 × 10-4 or 7.66 × 10-4 in the PUMA 1960 + sub-cohort, respectively. The LEAR per WLM estimates derived from risk models reported for previously published uranium miners studies range from 2.5 × 10-4 to 9.2 × 10-4. PUMA strengthens knowledge on the radon-related lung cancer LEAR, a useful way to translate models for policy purposes.

Estimating the burden of lung cancer in Canada attributed to occupational radon exposure using a novel exposure assessment method.

OBJECTIVE: Exposure to radon causes lung cancer. The scope and impact of exposure among Canadian workers have not been assessed. Our study estimated occupational radon exposure in Canada and its associated lung cancer burden. METHODS: Exposed workers were identified among the working population during the risk exposure period (1961-2001) using data from the Canadian Census and Labour Force Survey. Exposure levels were assigned based on 12,865 workplace radon measurements for indoor workers and assumed to be 1800 mg/m3 for underground workers. Lung cancer risks were calculated using the Biological Effects of Ionizing Radiation (BEIR) VI exposure-age-concentration model. Population attributable fractions were calculated with Levin's equation and applied to 2011 Canadian lung cancer statistics. RESULTS: Approximately 15.5 million Canadian workers were exposed to radon during the risk exposure period. 79% of exposed workers were exposed to radon levels < 50 Bq/m3 and 4.8% were exposed to levels > 150 Bq/m3. We estimated that 0.8% of lung cancers in Canada were attributable to occupational radon exposure, corresponding to approximately 188 incident lung cancers in 2011. CONCLUSIONS: The lung cancer burden associated with occupational radon exposure in Canada is small, with the greatest burden occurring among those exposed to low levels of radon.

Burden of non-melanoma skin cancer attributable to occupational sun exposure in Canada.

PURPOSE: Outdoor workers are exposed daily to solar ultraviolet radiation, an important contributor in the development of non-melanoma skin cancer. This study aimed to quantify the health burden of non-melanoma skin cancers among outdoor workers in Canada. METHODS: Solar ultraviolet radiation exposure and estimates of exposure levels were applied to employment information from Canada census data to determine the exposed population in the risk exposure period (1961-2001). Risk estimates were drawn from meta-analyses selected based on quality and relevance to the current study. Population-attributable fractions were calculated using Levin's equation and attributable cases were estimated based on incidence data reported by the Canadian Cancer Society. RESULTS: In 2011, 6.31% (4556 cases) of non-melanoma skin cancer cases were estimated to be attributable to occupational exposure to solar ultraviolet radiation. The majority of these cases occurred in men in the agriculture or construction industries. CONCLUSIONS: These estimates of the burden of non-melanoma skin cancer in Canada identify the need for further prevention efforts, particularly in agriculture and construction. Introducing workplace sun safety measures could be an important area for policy development.

Characteristics of work-related fatal and hospitalised injuries not captured in workers' compensation data.

OBJECTIVES: (1) To identify work-related fatal and non-fatal hospitalised injuries using multiple data sources, (2) to compare case-ascertainment from external data sources with accepted workers' compensation claims and (3) to investigate the characteristics of work-related fatal and hospitalised injuries not captured by workers' compensation. METHODS: Work-related fatal injuries were ascertained from vital statistics, coroners and hospital discharge databases using payment and diagnosis codes and injury and work descriptions; and work-related (non-fatal) injuries were ascertained from the hospital discharge database using admission, diagnosis and payment codes. Injuries for British Columbia residents aged 15-64 years from 1991 to 2009 ascertained from the above external data sources were compared to accepted workers' compensation claims using per cent captured, validity analyses and logistic regression. RESULTS: The majority of work-related fatal injuries identified in the coroners data (83%) and the majority of work-related hospitalised injuries (95%) were captured as an accepted workers' compensation claim. A work-related coroner report was a positive predictor (88%), and the responsibility of payment field in the hospital discharge record a sensitive indicator (94%), for a workers' compensation claim. Injuries not captured by workers' compensation were associated with female gender, type of work (natural resources and other unspecified work) and injury diagnosis (eg, airway-related, dislocations and undetermined/unknown injury). CONCLUSIONS: Some work-related injuries captured by external data sources were not found in workers' compensation data in British Columbia. This may be the result of capturing injuries or workers that are ineligible for workers' compensation, or the result of injuries that go unreported to the compensation system. Hospital discharge records and coroner reports may provide opportunities to identify workers (or family members) with an unreported work-related injury and to provide them with information for submitting a workers' compensation claim.

Characterizing occupational radon exposure greater than 100 Bq/m3 in a highly exposed country.

Radon is an established lung carcinogen concentrating in indoor environments with importance for many workers worldwide. However, a systematic assessment of radon levels faced by all workers, not just those with direct uranium or radon exposure, has not previously been completed. The objective of this study was to estimate the prevalence of workers exposed to radon, and the level of exposure (> 100-200 Bq/m3, 200-400 Bq/m3, 400-800 Bq/m3, and > 800 Bq/m3) in a highly exposed country (Canada). Exposures among underground workers were assessed using the CAREX Canada approach. Radon concentrations in indoor workplaces, obtained from two Canadian surveys, were modelled using lognormal distributions. Distributions were then applied to the susceptible indoor worker population to yield the number of exposed workers, by occupation, industry, province, and sex. In total, an estimated 603,000 out of Canada's 18,268,120 workers are exposed to radon in Canada. An estimated52% of exposed workers are women, even though they comprise only 48% of the labour force. The majority (68%) are exposed at a level of > 100-200 Bq/m3. Workers are primarily exposed in educational services, professional, scientific and technical services, and health care and social assistance, but workers in mining, quarrying, and oil and gas extraction have the largest number of exposed workers at high levels (> 800 Bq/m3). Overall, a significant number of workers are exposed to radon, many of whom are not adequately protected by existing guidelines. Radon surveys across multiple industries and occupations are needed to better characterize occupational exposure. These results can be used to identify exposed workers, and to support lung cancer prevention programs within these groups.

Mortality among uranium miners in North America and Europe: the Pooled Uranium Miners Analysis (PUMA).

BACKGROUND: The Pooled Uranium Miners Analysis (PUMA) study draws together information from cohorts of uranium miners from Canada, the Czech Republic, France, Germany and the USA. METHODS: Vital status and cause of death were ascertained and compared with expectations based upon national mortality rates by computing standardized mortality ratios (SMRs) overall and by categories of time since first hire, calendar period of first employment and duration of employment as a miner. RESULTS: There were 51 787 deaths observed among 118 329 male miners [SMR = 1.05; 95% confidence interval (CI): 1.04, 1.06]. The SMR was elevated for all cancers (n = 16 633, SMR = 1.23; 95% CI: 1.21, 1.25), due primarily to excess mortality from cancers of the lung (n = 7756, SMR = 1.90; 95% CI: 1.86, 1.94), liver and gallbladder (n = 549, SMR = 1.15; 95% CI: 1.06, 1.25), larynx (n = 229, SMR = 1.10; 95% CI: 0.97, 1.26), stomach (n = 1058, SMR = 1.08; 95% CI: 1.02, 1.15) and pleura (n = 39, SMR = 1.06; 95% CI: 0.75, 1.44). Lung-cancer SMRs increased with duration of employment, decreased with calendar period and persisted with time since first hire. Among non-malignant causes, the SMR was elevated for external causes (n = 3362, SMR = 1.41; 95% CI: 1.36, 1.46) and respiratory diseases (n = 4508, SMR = 1.32; 95% CI: 1.28, 1.36), most notably silicosis (n = 814, SMR = 13.56; 95% CI: 12.64, 14.52), but not chronic obstructive pulmonary disease (n = 1729, SMR = 0.98; 95% CI: 0.93, 1.02). CONCLUSIONS: Whereas there are important obstacles to the ability to detect adverse effects of occupational exposures via SMR analyses, PUMA provides evidence of excess mortality among uranium miners due to a range of categories of cause of death. The persistent elevation of SMRs with time since first hire as a uranium miner underscores the importance of long-term follow-up of these workers.

Early changes in respiratory health in trades' apprentices and physician visits for respiratory illnesses later in life.

OBJECTIVES: An inception cohort of trades' apprentices had rapid declines in lung function (forced expiratory volume in 1 s (FEV(1))) and rapid increases in bronchial responsiveness ( upward arrowBR) over the first 2 years of employment. We used physician visit data to assess respiratory health over the following 13 years. METHODS: Construction painter, electrician, insulator and machinist apprentices beginning at a British Columbia trade school in 1988 were invited to participate and were followed up 2 years later. Subjects were linked to provincial medical databases to examine physician visits for asthma and other respiratory illnesses for the 13 years following. Multivariable models with rapid decline in FEV(1) and rapid increase in BR from years 1 to 3 were constructed. Respiratory symptoms were also examined as predictors of visit rates and meeting a case definition (for asthma or other respiratory illness). RESULTS: The cohort included 281 apprentices (97% are men). Sixteen subjects met the asthma case definition (>or=2 visits coded as asthma in 1 year) and 20 met the other respiratory illness case definition (>or=3 visits for bronchitis, emphysema, respiratory symptoms in 1 year). In models controlling for demographic factors and smoking, subjects with bronchitis symptoms at baseline were more likely to develop other respiratory illness during follow-up (RR 4.4, 95% CI 1.6 to 11.9). Apprentices who developed asthma symptoms over the first 2 years were approximately six times more likely to become asthma cases (95% CI 1.9 to 18.8). Those with a rapid increase in BR were at increased risk of becoming asthma cases (RR 5.5, 95% CI 1.9 to 16.1), as well as having higher asthma visit rates (RR 6.5). Subjects with rapid decline in FEV(1) were 3.2 times more likely to become asthma cases (95% CI 0.8 to 12.1). CONCLUSIONS: Changes in respiratory health early in adulthood, especially increased BR, are associated with respiratory physician visits. These findings are important for workplace screening and prevention and also suggest that physician visit databases are promising research tools in respiratory epidemiology.

Population-based asbestosis surveillance in British Columbia.

OBJECTIVES: To investigate the use of multiple health data sources for population-based asbestosis surveillance in British Columbia, Canada. METHODS: Provincial health insurance registration records, workers' compensation records, hospitalisation records, and outpatient medical service records were linked using individual-specific study identifiers. The study population was restricted to individuals > or = 15 years of age living in the province during 1992-2004. RESULTS: 1170 new asbestosis cases were identified from 1992 to 2004 for an overall incidence rate of 2.82 (men: 5.48, women: 0.23) per 100,000 population; 96% of cases were male and average (SD) age was 69 (10) years. Although the annual number of new cases increased by 30% during the surveillance period (beta = 2.36, p = 0.019), the observed increase in annual incidence rates was not significant (beta = 0.02, p = 0.398). Workers' compensation, hospitalisation and outpatient databases identified 23%, 48% and 50% of the total new cases, respectively. Of the new cases, 82% were identified through single data sources, 10% were only recorded in the workers' compensation records, and 36% only in each of the hospitalisation and outpatient records. 84% of hospitalisation cases and 83% of outpatient cases were not included in the workers' compensation records. The three data sources showed different temporal trends in the annual number of new cases and annual incidence rates. CONCLUSIONS: Single data sources were not sufficient to identify all new cases, thus leading to serious underestimations of the true burden of asbestosis. Integrating multiple health data sources could provide a more complete picture in population-based surveillance of asbestosis and other occupational diseases.

A retrospective assessment of occupational noise exposures for a longitudinal epidemiological study.

OBJECTIVES: Chronic exposure to high levels of noise may be associated with increased risk of cardiovascular disease. We therefore undertook a quantitative retrospective exposure assessment using predictive statistical modelling to estimate historical exposures to noise among a cohort of 27,499 sawmill workers as part of an investigation of acute myocardial infarction mortality. METHODS: Noise exposure data were gathered from research, industry and regulatory sources. An exposure data matrix was defined and exposure level estimated for job title/mill/time period combinations utilising regression analysis to model determinants of noise exposure. Cumulative exposure and duration of exposure metrics were calculated for each subject. These were merged with work history data, and exposure-response associations were tested in subsequent epidemiological studies, reported elsewhere. RESULTS: Over 14,000 noise measurements were obtained from British Columbia sawmills. A subset, comprising 1901 full-shift dosimetry measurements from cohort mills was used in producing a predictive model (R(2) = 0.51). The model was then used to estimate noise exposures for 3809 "cells" of an exposure data matrix representing 81 jobs at 14 mills over several decades. Various exposure metrics were then calculated for subjects; mean cumulative exposure was 101 dBA*year. Mean durations of employment in jobs with exposure above thresholds of 85, 90 and 95 dBA, were 9.9, 7.0 and 3.2 years, respectively. CONCLUSIONS: The utility of predictive statistical modelling for occupational noise exposure was demonstrated. The model required input data that were relatively easily obtained, even retrospectively. Remaining issues include adequate handling of the use of hearing protectors that likely bias exposure estimation.

Hypertension in noise-exposed sawmill workers: a cohort study.

OBJECTIVE: To investigate the hypothesised association between exposure to high levels of noise and risk of hypertension using quantitative exposure assessment and administrative health data. METHODS: This study followed a cohort of 10 872 sawmill workers in British Columbia from 1991 to 1998. Subjects were linked with provincial hospital discharge, outpatient and vital status databases. Cases were males who died, had at least one hospital admission, or who had three doctor visits within 70 days, for hypertension (ICD-9 codes 401-405). We used four exposure metrics: cumulative exposure, and duration of exposure above thresholds of 85 dBA, 90 dBA and 95 dBA. Relative risks were estimated using Poisson regression with the low-exposure group as controls and adjusting for age, ethnicity and calendar period. RESULTS: 828 cases were identified. The results showed a monotonic increase in hypertension incidence with cumulative exposure. The risk in the highest exposed population was 32% higher than baseline. Similar results were found using duration of exposure metrics. The highest relative risk was 1.5 in workers exposed for more than 30 years at 85 dBA. Exposure-response trends were statistically significant. CONCLUSIONS: The risk of hypertension was positively associated with noise exposure above 85 dB.

Silica exposure in a mining exploration operation.

BACKGROUND: Though there is extensive research on occupational exposure in production mines, there is limited information on exposure during the exploration phase of mining. METHODS: Air samples were collected in a core processing facility in Northern Ontario, Canada. All samples were analyzed for respirable dust (NIOSH 0600) and respirable crystalline silica (NIOSH 7602). Mean exposure levels were estimated and differences in exposure between work areas were investigated. RESULTS: Sixteen personal and nine area air samples were collected. Respirable dust exposure ranged from < LOD to 2.24mg-m-3; respirable silica exposure ranged from < LOD to 0.055mg-m-3. Silica concentrations were higher among workers in the core cutting and core sorting (pulp and reject) areas, as compared to those in the core logging area. CONCLUSIONS: Workers employed in core processing facilities as part of mining exploration activities are exposed to respirable silica; exposure controls may be needed.

Challenges and Opportunities for Occupational Epidemiology in the Twenty-first Century.

PURPOSE OF REVIEW: There are many opportunities and challenges for conducting occupational epidemiologic studies today. In this paper, we summarize the discussion of a symposium held at the Epidemiology in Occupational Health (EPICOH) conference, Chicago 2014, on challenges for occupational epidemiology in the twenty-first century. RECENT FINDINGS: The increasing number of publications and attendance at our conferences suggests that worldwide interest in occupational epidemiology has been growing. There are clearly abundant opportunities for new research in occupational epidemiology. Areas ripe for further work include developing improved methods for exposure assessment, statistical analysis, studying migrant workers and other vulnerable populations, the use of biomarkers, and new hazards. Several major challenges are also discussed such as the rapidly changing nature and location of work, lack of funding, and political/legal conflicts. As long as work exists there will be occupational diseases that demand our attention, and a need for epidemiologic studies designed to characterize these risks and to support the development of preventive strategies. Despite the challenges and given the important past contribution in this field, we are optimistic about the importance and continued vitality of the research field of occupational epidemiology.

Childhood cancer in the offspring of male sawmill workers occupationally exposed to chlorophenate fungicides.

The objective of this study was to determine whether paternal occupational exposure to chlorophenol fungicides and their dioxin contaminants is associated with childhood cancer in the offspring of sawmill workers. We used data from 23,829 British Columbian sawmill workers employed for at least 1 continuous year between 1950 and 1985 in 11 sawmills that used chlorophenates. Probabilistic linkage of the sawmill worker cohort to the provincial marriage and birth files produced an offspring cohort of 19,674 children born at least 1 year after the initiation of employment in the period 1952-1988. We then linked the offspring cohort to the British Columbia Cancer Registry. We included all malignancies in cases younger than 20 years of age that appeared on the cancer registry between 1969 and 1993. We calculated standardized incidence ratios (SIRs) using the British Columbia population as a reference. A nested case-control analysis assessed the effects of paternal cumulative exposure and windows of exposure on the risk of developing cancer in the offspring. We identified 40 cases of cancer during 259,919 person-years of follow-up. The all-cancer SIR was 1.0 [95% confidence interval (CI), 0.7-1.4]; the SIR for leukemia was 1.0 (CI, 0.5-1.8); and the SIR for brain cancer was 1.3 (CI, 0.6-2.5). The nested case-control analysis showed slightly increased risks in the highest categories of chlorophenol exposure, although none was statistically significant. Our analyses provide little evidence to support a relationship between the risk of childhood cancer and paternal occupational exposure to chlorophenate fungicides in British Columbian sawmills.

Effect of de-industrialisation on working conditions and self reported health in a sample of manufacturing workers.

STUDY OBJECTIVE: To explore the impact of de-industrialisation over a 20 year period on working conditions and health among sawmill workers, in the province of British Columbia (BC), Canada. DESIGN AND SETTING: This investigation is based on a sample of 3000 sawmill workers employed in 1979 (a year before the beginning de-industrialisation) and interviewed in 1998. The sample was obtained by random selection from an already gathered cohort of approximately 28 000 BC sawmill workers. Change in working conditions from 1979 to 1998 are described. Self reported health status, in 1998, was used as a dependent variable in logistic regression after controlling for confounders. MAIN RESULTS: Downsizing in BC sawmills eliminated 60% of workers between 1979 and 1998. Working conditions in 1998 were better for those who left the sawmill industry and obtained re-employment elsewhere. Workers who remained employed in restructuring sawmills were approximately 50% more likely to report poor health than those re-employed elsewhere. CONCLUSIONS: Working conditions and health status were better for workers who, under pressure of de-industrialisation, left the sawmill industry and obtained re-employment outside this sector.

Lymphocytopenia and occupational exposures among pattern and model makers.

OBJECTIVES: The study was performed to examine the relationship between a high prevalence of lymphocytopenia observed during a cancer screening program for pattern and model makers, who produce industrial prototypes and patterns, and 15 occupational exposures. METHODS: The cases (N = 83) were workers with lymphocyte counts of less than 1000, while the referents (N = 529) had counts of 1500 or higher. Exposures at the current workplace, and at up to 19 previous pattern and model shops, were assessed with the use of a questionnaire. RESULTS: Elevated risks were associated with exposure to epoxy resins [odds ratio (OR) 1.94, 95% confidence interval (95% CI) 1.02-3.70) and plastic dusts (OR 2.60, 95% CI 1.19-5.68) after adjustment for age and smoking status. No clear associations were found with duration of exposure or percentage of time potentially exposed. Although the results were based upon small numbers, epoxy resins and wood dust displayed the most consistent relationships in an analysis of changes in lymphocyte count and exposure status over time. CONCLUSION: While firm conclusions cannot be drawn, the strongest associations observed in this study were for exposure to epoxy resins.

Carpal tunnel syndrome among ski manufacturing workers.

Carpal tunnel syndrome is a common disorder marked by pain and dysesthesias of the upper extremities. As a test of the hypothesis that carpal tunnel syndrome is associated with occupational risk factors, jobs at a ski assembly plant were classified as repetitive and nonrepetitive. The prevalence of carpal tunnel syndrome among 106 employees with repetitive jobs was compared with that among 67 employees with nonrepetitive jobs. The data collection included a questionnaire, a physical examination, and the measurement of distal sensory latencies of the median and ulnar nerves. Carpal tunnel syndrome was present in either or both hands in 15.4% of those workers with repetitive jobs, but only in 3.1% of those workers with nonrepetitive jobs (crude prevalence ratio 4.92, 95% confidence interval 1.17-20.7). The conclusion was drawn that carpal tunnel syndrome is associated with jobs requiring frequent and sustained hand work.

Pooled reanalysis of cancer mortality among five cohorts of workers in wood-related industries.

OBJECTIVES: To provide more information regarding the risk of cancer associated with wood dust, a pooled reanalysis of data from five cohort studies was performed. METHODS: The combined cohort consisted of 28,704 persons from five studies: British furniture workers, members of the union representing furniture workers in the United States, two cohorts of plywood workers, and one of wood model makers, among whom 7665 deaths occurred. Pooled analyses were carried out for all of the cohorts combined, the two furniture worker cohorts combined, and the two plywood workers cohorts combined. RESULTS: Significant excesses of nasal [observed 11, standardized mortality ratio (SMR) 3.1, 95% confidence interval (95% CI) 1.6-5.6] and nasopharyngeal (observed 9, SMR 2.4, 95% CI 1.1-4.5) cancer were observed. That for nasal cancer appeared to be associated with exposure to wood dust but was based solely on cases from the British furniture worker cohort, while that of nasopharyngeal cancer was observed for furniture and plywood workers and was associated with both high and low probability of wood dust exposure. Some support for an excess risk of multiple myeloma was also observed but was less clearly associated with wood dust exposure. No excesses of lung, larynx, stomach, or colon cancer were found to be associated with any surrogate indicators of wood dust exposure. CONCLUSIONS: Workers exposed to wood dust may have an excess risk of nasopharyngeal cancer and multiple myeloma in addition to sinonasal cancer. The limitations of this study would tend to obscure relationships, rather than create false positive findings.

Comparison of expert-rater methods for assessing psychosocial job strain.

OBJECTIVES: This study tested the reliability and validity of industry- and mill-level expert methods for measuring psychosocial work conditions in British Columbia sawmills using the demand-control model. METHODS: In the industry-level method 4 sawmill job evaluators estimated psychosocial work conditions at a generic sawmill. In the mill-level method panels of experienced sawmill workers estimated psychosocial work conditions at 3 sawmills. Scores for psychosocial work conditions were developed using both expert methods and applied to job titles in a sawmill worker database containing self-reported health status and heart disease. The interrater reliability and the concurrent and predictive validity of the expert rater methods were assessed. RESULTS: The interrater reliability and concurrent reliability were higher for the mill-level method than for the industry-level method. For all the psychosocial variables the reliability for the mill-level method was greater than 0.90. The predictive validity results were inconclusive. CONCLUSIONS: The greater reliability and concurrent validity of the mill-level method indicates that panels of experienced workers should be considered as potential experts in future studies measuring psychosocial work conditions.

Opportunities for a broader understanding of work and health: multiple uses of an occupational cohort database.

Occupational cohort studies conducted to study cancer incidence and mortality require extensive data gathering about workers' job histories, exposures, and health outcomes. Although this process is expensive, the database created can be looked upon as a resource for broad investigations of the relationship between work and health. This paper presents the example of a retrospective cohort study which began in the traditional way, examining the link between a specific pesticide exposure and mortality and cancer incidence. The cohort register has since been used to investigate whether infertility, adverse reproductive outcomes, and childhood cancers might be associated with this exposure. It is also being used as the basis for studying other sawmill exposures including noise and wood dust as well as socioeconomic factors including job strain, job mobility, unemployment, and retraining. This approach allows both the efficient use of occupational cohorts as well as providing the opportunity for investigators to develop a more comprehensive perspective on the determinants of the health status of workers and their families.