Research

Modelling prevalence and incidence of fibrosis and pleural plaques in asbestos-exposed populations for screening and follow-up: a cross-sectional study

Christophe Paris^1,2 , Aurélie Martin¹ , Marc Letourneux³ and Pascal Wild⁴

¹Inserm ERI-11, Assessment and prevention of occupational and environmental risks Medical School, 9 av de la Forêt de Haye – BP 184, 54505 Vandoeuvre-les-Nancy Cedex, France

²Nancy-University, 1 rue Lyautey, 54000 Nancy, France

³Occupational Diseases Department, University Hospital, Avenue de la cote de Nacre, 14000 CAEN, France

⁴Département Epidémiologie en Entreprises, Rue du Morvan, CS 60027,54519 Vandoeuvre Les Nancy Cedex, France

author email corresponding author email

Environmental Health 2008, 7:30doi:10.1186/1476-069X-7-30

Published:	20 June 2008

Abstract

Background

CT-Scan is currently under assessment for the screening of asbestos-related diseases. However, to date no consensus exists as to how to select high-risk asbestos-exposed populations suitable for such screening programs. The objective of this study is to select the most relevant exposure variables for the prediction of pleural plaques and asbestosis in order to guide clinicians in their use of CT-Scan.

Methods

A screening program of non malignant asbestos-related diseases by CT-scan was conducted among asbestos-exposed volunteers in France. Precise assessments of asbestos exposure were obtained by occupational hygiene measurements and a job-exposure matrix. Several parameters were calculated (time since first exposure, duration, intensity and cumulative exposure to asbestos). Predictive parameters of prevalence and incidence were then estimated by standard logistic and a complementary log-log regression models.

Results

1011 subjects were recruited in this screening program among them 474 (46.9%) presented with pleural plaques and 61 (6.0%) with interstitial changes compatible with asbestosis on CT-scan. Time since first exposure (p < 0.0001) and either cumulative or mean exposure (p < 0.0001) showed independent associations with both pleural plaques and asbestosis prevalence and pleural plaques incidence. Modelling incidence of pleural plaques showed a 0.8% to 2.4% yearly increase for a mean exposure of 1 f/ml.

Conclusion

Our findings confirmed the role played by time since first exposure and dose but not duration in asbestos-related diseases. We recommend to include these parameters in high-risk populations suitable for screening of these diseases. Short-periodicity of survey of pleural plaques by CT-Scan seemed not to be warranted.