[Asbestos and risk of cancer: exposure-effect relationships for occupationally exposed populations]

For high levels of exposure (> 1 f/ml), the risk of lung cancer increases linearly with the cumulative exposure, and is the same for all types of asbestos; the risk of mesothelioma increases linearly with the level of exposure, is time dependent and higher for amphiboles. The effects of asbestos and smoking for lung cancer are independent, and the probability that a cancer is due to asbestos is the same among smokers and non-smokers. There is no scientific method for quantifying directly the risks associated to low levels of exposure (< 1 f/ml). The only possible approach is to extrapolate from the risks observed at high levels to low levels. Proportionality without threshold between dose and risk is not certain, but is the most plausible model. Using this model, one can expect about 30 additional cases of cancer for 10,000 men exposed at the level of 0.1 f/ml from 20 to 65 years, and about 16 additional cases for 10,000 women. These are high figures compared to other health hazards.