M. Houot

Matgene: A Program to Develop Job-Exposure Matrices in the General Population in France

OBJECTIVES Matgéné is a program to develop job-exposure matrices (JEMs) adapted to the general population in France for the period since 1950. The aim is to create retrospective exposure assessment tools for estimating the prevalence of occupational exposure to various agents that can then be correlated to health-related parameters. METHODS JEMs were drawn up by a team of six industrial hygienists who based their assessments on available occupational measurement, economic and statistical data, and several thousand job descriptions from epidemiological studies performed in France since 1984. Each JEM is specific to one agent, assessing exposure for a set of homogeneous combinations (occupation × activity × period) according to two occupational classifications (ISCO 1968 and PCS 1994) and one economic activities classification (NAF 2000). The cells of the JEM carry an estimate of the probability and level of exposure. Level is estimated by the duration and intensity of exposure-linked tasks or by description of the tasks when exposure measurement data are lacking for the agent in question. The JEMs were applied to a representative sample of the French population in 2007, and prevalence for each exposure was estimated in various population groups. All documents and data are available on a dedicated website. RESULTS By the end of 2010, 18 JEMs have been developed and eight are under development, concerning a variety of chemical agents: organic and mineral dust, mineral fibers, and solvents. By implementation in the French population, exposure prevalences were calculated at different dates and for complete careers, and attributable risk fractions were estimated for certain pathologies. Some of these results were validated by comparison with those of other programs. DISCUSSION Initial Matgéné JEMs results are in agreement with the French and international literature, thus validating the methodology. Exposure estimates precision, however, vary between agents and according to the amount of exposure measurement data available. These JEMs are important epidemiological tools, and improving their quality will require investment in occupational health data harvesting, especially in the case of low-level exposures.

Temporal patterns of occupational asbestos exposure and risk of pleural mesothelioma.

Asbestos is the primary cause of pleural mesothelioma (PM). The objective of this study was to elucidate the importance of different temporal patterns of occupational asbestos exposure on the risk of PM using case–control data in male subjects. Cases were selected from a French case–control study conducted in 1987–1993 and the French National Mesothelioma Surveillance Program in 1998–2006. Population controls were frequency matched to cases by year of birth. Occupational asbestos exposure was evaluated with a job–exposure matrix. The dose–response relationships were estimated using restricted cubic spline functions in logistic regression models. A total of 2,466 ever-asbestos-exposed males (1,041 cases and 1,425 controls) were used. After adjustment for intensity and total duration of occupational asbestos exposure, the risk of PM was lower for subjects first exposed after the age of 20 yrs and continued to increase until 30 yrs after cessation of exposure. The effect of total duration of exposure decreased when age at first exposure and time since last exposure increased. These results, based on a large population-based case–control study, underline the need to take into account the temporal pattern of exposure on risk assessment.

0135 Prevalence of exposure to some occupational carcinogens in France: evolution between 1999 and 2007

Objectives To use job-exposure matrices (JEM), as a tool to describe trends of occupational exposure to carcinogenic chemicals present in the French workplace. Method MATGÉNÉ JEMs assess for each job and a given period in France, several exposure indices such as probability, intensity and frequency of exposure. Linking these matrices with job information data coming from French population allow to estimate the prevalence of workers exposed to several chemicals for a given year. To study the evolution of exposure to carcinogens, prevalence of exposure in France for the years 1999 and 2007 were estimated from the population census of 1999 and from a representative sample of the population in 2007. Results French available JEMs assess the exposure of workers since the 1950s for various occupational carcinogens: crystalline silica, benzene, trichlorethylene, perchlorethylene, leather dust, asbestos and refractory ceramic fibres (RCF). A significant decrease in the prevalence of exposure between 1999 and 2007 was observed among men for silica with 7.4% and 5.6% respectively, asbestos with 6.3% and 1.1% and RCF with 0.5% and 0.3%. For women, a significant decrease was also noticed for exposure to asbestos and leather dust. For solvents, the prevalence of exposure remained stable in both men and women. Conclusions The proportion of workers exposed to carcinogens, particularly to asbestos, has decreased in France since 1999. However a substantial number of workers are still exposed. As complete occupational histories are available in the 2007 population sample, the JEMs will also be used to estimate lifetime exposure prevalence and the associated disease burden.

Prediction model of asthma using antiasthma drug claims for epidemiological surveillance of asthma in self-employed workers in France

Objectives To develop a prediction model of asthma based on antiasthma drug claims among affiliates to the health insurance for self-employed workers in France. Methods A random sample of the affiliates, stratified on their drug claims for antiasthma medications, was selected in three regions in France. Drug claims data for the 3 previous years was used. Ten categories of antiasthma medications, demographic variables and medical examination were introduced in multivariate logistic regression. The performance of the prediction model was examined against current asthma defined by a self-administered questionnaire. Asthma estimated by the prediction model was used to study prevalence and odds-ratios according to economic activities. Results Among the 2753 respondents with antiasthma drug claims, 520 had current asthma. Variables retained in the model were short or long acting bronchodilator, inhaled glucocorticosteroid, long-acting inhaled bronchodilator combined with inhaled glucocorticosteroid, leukotriene modifiers, one antihistamine (ketotifen) and medical examinations by a chest physician. The area under the ROC curve was excellent (0.90). The optimal cut-off yielded a sensitivity of 80% and a specificity of 86%. Prevalence of current asthma estimated by the prediction model was 3.4%. Significantly elevated odds-ratios were observed in the production of food products and beverages (OR=2.2 (95% CI 1.7 to 2.7)) and in the manufacture of machinery and equipment (OR=2.0 (95% CI 1.0 to 4.0)). Conclusions Prediction models of asthma using antiasthma drug claims can be a useful tool for asthma surveillance in the working population. The next step is an external validation which will be carried out on workers of the agriculture industry.

0155 Use of a prediction model of asthma with antiasthma drug claims for epidemiological surveillance of asthma in self-employed workers in France

Objectives To estimate prevalence and risk of current asthma among affiliates to the health insurance for self-employed workers according to economic activities. Method We defined current asthma using a prediction model developed in a study conducted in 2006 among workers aged between 18 to 65, affiliated to the Régime Social des Indépendants (RSI) in three French regions. The model used as predictors antiasthma drug claims data and the prescriber’s medical speciality. In 2013, we obtained from the RSI, economic sectors and drug claims data of all French affiliates on whom we applied our prediction model. We used logistic regression to estimate asthma risk of each economic sector versus all the others. Results The population comprised 967391 workers. In men, the asthma prevalence was 5.6%. Elevated odds-ratios were observed in the production of food products (OR=1.70 [95% CI 1.63–1.78]), recycling (OR=1.44 [95% CI 1.23–1.70]), health and social work (OR=1.34 [95% CI 1.16–1.54]) and land transport (OR=1.08 [95% CI 1.03–1.13]). In women, the asthma prevalence was 7%. High odds-ratios were observed in education (OR=1.27 [95% CI 1.08–1.50]), manufacture of medical and precision instruments (OR=1.25 [95% CI 0.99–1.58]), land transport (OR=1.11 [95% CI 0.98–1.25]) and hotel/restaurants (OR=1.10 [95% CI 1.05–1.15]). Conclusions Prevalence estimated by the model was close to that observed among self-employed workers within a national survey conducted in 2003. Elevated risks were observed in several industries known to be at risk but also in those not expected. Prediction model approach will allow asthma surveillance in workers without interview with health insurance organisation data when occupational data are available.