Estimating past inhalation exposure to asbestos: a tool for risk attribution and disease screening. International Journal of Hygiene and Environmental Health

Introduction
Late presentation is common in mesothelioma. Reliable assessment of past exposure to asbestos is a necessary first step for risk attribution and for the development of a future screening programme. Such a programme could maximise access to trials of novel therapies and would pave the way for development of novel chemoprophylaxis strategies. This paper describes a method for individual exposure reconstruction along with data from a validation study.

Methods
The exposure assessment method uses only descriptive information about the circumstances of the work that could be obtained from questioning the worker. The assessment is based on the tasks carried out and includes parameters for substance emission potential, activity emission potential, the effectiveness of any local control measures, passive emission, the fractional time the asbestos source is active and the efficiency of any respiratory protection worn.

Results
There was a good association between the estimated and measured exposure levels. Pearson’s correlation coefficient between the log-transformed measurements and estimates from the model was 0.86, and 95% of the estimated individual values were within about a factor of ten of the associated measured value. The method described would be suitable for pre-selecting individuals at high risk of malignant pleural mesothelioma for screening using appropriate tools and/or enrolment in clinical trials of chemo-prophylaxis.

Discussion
This method is of potential clinical value in developing novel treatment approaches for mesothelioma. Pilot studies to test this approach are urgently needed.