Asbestos Fiber Concentrations in the Lungs of Brake Repair Workers: An Updated Analysis Using Several Regression Methods to Handle Non-Detectable Measurements

Journal of Occupational and Environmental Medicine 2018 March [Epub ahead of print] [Link]

Liu Y1, Marsh GM, Roggli VL


To reanalyze an updated database of lung asbestos fiber levels for 21 brake repair workers who died of mesothelioma using robust maximum likelihood-based regression methods to address non-detectable measurements.

We applied bivariate normal regression to address the doubly left-censored situation where both the lung fiber concentration of non-commercial (TAA) and commercial amphiboles (AC) were subject to detection limits. For the single left-censored situation, we applied censored normal regression to study the relationship between duration of employment (DOE) and TAA.

We found a statistically significant positive relationship between TAA and AC (β = 0.49, 95%CI 0.11-0.86) and a not statistically significant relationship between DOE and TAA (β = 0.02, 95%CI -0.03-0.06).

Our results provide additional support for the conclusion that exposure to commercial amphibole asbestos, and not chrysotile, is related to the occurrence of mesothelioma among some brake workers.