Lessons learned while compiling a quantitative exposure database from the published literature

15 years of monitoring occupational exposure to respirable dust and quartz within the European industrial minerals sector

INTRODUCTION

In 2000, a prospective Dust Monitoring Program (DMP) was started in which measurements of worker's exposure to respirable dust and quartz are collected in member companies from the European Industrial Minerals Association (IMA-Europe). After 15 years, the resulting IMA-DMP database allows a detailed overview of exposure levels of respirable dust and quartz over time within this industrial sector. Our aim is to describe the IMA-DMP and the current state of the corresponding database which due to continuation of the IMA-DMP is still growing. The future use of the database will also be highlighted including its utility for the industrial minerals producing sector.

METHODS

Exposure data are being obtained following a common protocol including a standardized sampling strategy, standardized sampling and analytical methods and a data management system. Following strict quality control procedures, exposure data are consequently added to a central database. The data comprises personal exposure measurements including auxiliary information on work and other conditions during sampling.

RESULTS

Currently, the IMA-DMP database consists of almost 28,000 personal measurements which have been performed from 2000 until 2015 representing 29 half-yearly sampling campaigns. The exposure data have been collected from 160 different worksites owned by 35 industrial mineral companies and comes from 23 European countries and approximately 5000 workers.

CONCLUSION

The IMA-DMP database provides the European minerals sector with reliable data regarding worker personal exposures to respirable dust and quartz. The database can be used as a powerful tool to address outstanding scientific issues on long-term exposure trends and exposure variability, and importantly, as a surveillance tool to evaluate exposure control measures. The database will be valuable for future epidemiological studies on respiratory health effects and will allow for estimation of quantitative exposure response relationships.

Exposed! Or not? The diminishing record of workplace exposure in Canada

The Canadian Workplace Exposure Database (CWED) is the first of its kind in Canada. It was originally developed in 2008 by the Canadian Carcinogen Exposure project (CAREX Canada) to assist in estimating worker exposures to carcinogens across the country.Following the CWED's establishment, all Canadian federal and provincial agencies responsible for administering occupational health and safety regulation were surveyed to obtain a clearer picture of the quantity and quality of regulatory exposure data available. This revealed troubling reductions in exposure measurement collection, retention, and centralization by these agencies in recent years.Such trends will limit access to workplace exposure measurements for federal and provincial regulatory agencies as well as health researchers. Workplace exposure databases are used around the world for a variety of important purposes, such as identifying hazardous workplaces and workers at risk, assessing temporal-spatial trends, setting priorities for prevention, and informing epidemiological research.Efforts are underway to preserve historical data and promote prospective collection, however future success of the CWED will require collaboration and long-term vision on the part of those responsible for collecting workplace exposure measurements in Canada.

Statistical modeling of crystalline silica exposure by trade in the construction industry using a database compiled from the literature

A quantitative determinants-of-exposure analysis of respirable crystalline silica (RCS) levels in the construction industry was performed using a database compiled from an extensive literature review. Statistical models were developed to predict work-shift exposure levels by trade. Monte Carlo simulation was used to recreate exposures derived from summarized measurements which were combined with single measurements for analysis. Modeling was performed using Tobit models within a multimodel inference framework, with year, sampling duration, type of environment, project purpose, project type, sampling strategy and use of exposure controls as potential predictors. 1346 RCS measurements were included in the analysis, of which 318 were non-detects and 228 were simulated from summary statistics. The model containing all the variables explained 22% of total variability. Apart from trade, sampling duration, year and strategy were the most influential predictors of RCS levels. The use of exposure controls was associated with an average decrease of 19% in exposure levels compared to none, and increased concentrations were found for industrial, demolition and renovation projects. Predicted geometric means for year 1999 were the highest for drilling rig operators (0.238 mg m(-3)) and tunnel construction workers (0.224 mg m(-3)), while the estimated exceedance fraction of the ACGIH TLV by trade ranged from 47% to 91%. The predicted geometric means in this study indicated important overexposure compared to the TLV. However, the low proportion of variability explained by the models suggests that the construction trade is only a moderate predictor of work-shift exposure levels. The impact of the different tasks performed during a work shift should also be assessed to provide better management and control of RCS exposure levels on construction sites.

Systematic review of fibroadenoma as a risk factor for breast cancer

Fibroadenoma (FA) is a common breast lesion occurring in 25% of asymptomatic women. Several studies considered FA as a risk factor for breast cancer, prompting a systematic review of the literature. We selected cohort and case-control studies. Seven studies satisfied the selection criteria. Dupont et al. (1994) and McDivitt et al. (1992) were considered to provide the strongest evidence, showing the relative risk for excised FA without hyperplasia in the range 1.48-1.7, with hyperplasia 3.47-3.7, and with hyperplasia and atypia 6.9-7.29, persisting for more than 20 years. Five studies by Levi et al. (1994), Ciatto et al. (1997), Moskowitz et al. (1980), Carter et al. (1988), and Levshin et al. (1998), were considered to provide weaker evidence, although they showed similar results. None of the results could be used to quantify the risks of excised, non-excised, and asymptomatic FA. More care should be taken in managing patients with complex FAs and FAs with hyperplasia with or without atypia. Core biopsy may be a better option in diagnosis of FAs. Regular screening may be advisable in patients with FAs and a family history of breast cancer in a first-degree relative. More rigorous research is needed in this area.