Occupational exposure to unintentionally emitted nanoscale particles and risk of cancer: From lung to central nervous system - Results from three French case-control studies.

OBJECTIVES: Nanoscale particles (1-100 nm) can be of natural origin, and either intentionally or unintentionally produced by human activities. Toxicological data have suggested a possible carcinogenic effect of such particles. The aim of this study was to estimate the association between occupational exposure to nanoscale particles and risk of lung cancer, pleural mesothelioma and brain tumors in adults. METHODS: Three French population-based case-control studies were analyzed: 1) the ICARE study including 2029 lung cancer cases and 2591 controls; 2) the PNSM study including 371 pleural mesothelioma cases and 730 controls and 3) the CERENAT study including 257 brain tumor cases and 511 controls. Occupational exposure to unintentionally emitted nanoscale particles (UNPs) was retrospectively assessed by a job exposure matrix providing a probability and a frequency of exposure. RESULTS: In adjusted analyses among men, significant associations between occupational exposure to UNPs and lung cancer (OR = 1.51; 95% CI: 1.22-1.86 and brain tumors (OR = 1.69; 95% CI: 1.17-2.44) were observed. No increased OR was observed for pleural mesothelioma (OR = 0.78; 95% CI: 0.46-1.33). CONCLUSION: This is the first study showing positive associations between occupational exposure to UNPs and increased risk of lung cancer and brain tumors. These preliminary results should encourage further epidemiological research.

Geographic dimensions of a health network dedicated to occupational and work related diseases.

BACKGROUND: Although introduced nearly 40 years ago, Geographic Information Systems (GISs) have never been used to study Occupational Health information regarding the different types, scale or sources of data. The geographic distribution of occupational diseases and underlying work activities were always analyzed independently. Our aim was to consider the French Network of Occupational Disease (OD) clinics, namely the "French National OD Surveillance and Prevention Network" (rnv3p) as a spatial object in order to describe its catchment. METHODS: We mapped rnv3p observations at the workplace level. We initially analyzed rnv3p capture with reference to its own data, then to the underlying workforce (INSEE "Employment Areas"), and finally compared its capture of one emblematic occupational disease (mesothelioma) to an external dataset provided by a surveillance system thought to be exhaustive (PNSM). RESULTS: While the whole country is covered by the network, the density of observations decreases with increase in the distance from the 31 OD clinics (located within the main French cities). Taking into account the underlying workforce, we show that the probability to capture and investigation of OD (assessed by rates of OD per 10,000 workers) also presents large discrepancies between OD clinics. This capture rate might also show differences according to the disease, as exemplified by mesothelioma. CONCLUSION: The geographic approach to this network, enhanced by the possibilities provided by the GIS tool, allow a better understanding of the coverage of this network at a national level, as well as the visualization of capture rates for all OD clinics. Highlighting geographic and thematic shading zones bring new perspectives to the analysis of occupational health data, and should improve occupational health vigilance and surveillance.

Co-exposure to refractory ceramic fibres and asbestos and risk of pleural mesothelioma.

The aim of this study was to investigate the hypothesis of an increased risk of pleural mesothelioma due to co-exposure to asbestos and refractory ceramic fibres (RCF) compared to asbestos exposure alone. Males were selected from a French case-control study conducted in 1987-1993 and from the French National Mesothelioma Surveillance Program in 1998-2006. Two population controls were frequency matched to each case by year of birth. Complete job histories were collected and occupational asbestos and RCF exposures were assessed using job exposure matrices. The dose-response relationships for asbestos exposure were estimated from an unconditional logistic regression model in subjects exposed to asbestos only (group 1) and subjects exposed to both asbestos and RCF (group 2). A total of 988 cases and 1125 controls ever-exposed to asbestos were included. A dose-response relationship was observed in both groups but it was stronger in group 2. In comparison with subjects exposed at the minimum value of the cumulative index of exposure, the odds ratio was 2.6 (95% CI 1.9-3.4) for subjects exposed to 75 fibres · mL(-1) · year(-1) in group 1 increasing to 12.4 (95% CI 4.6-33.7) in group 2. Our results suggest that the pleural carcinogenic effect of occupational asbestos exposure may be modified by additional exposure to RCF.