Objectives Occupational exposure to asbestos is associated with increased morbidity and mortality. The effectiveness of regulations to control exposure is yet to be determined due to the long latency of asbestos-related diseases. The study objectives were to examine mortality trends in a large cohort of asbestos workers in relation to the implementation of the 1983 Asbestos Licensing Regulations (ALR).

Methods The study population consisted of British asbestos workers undergoing regular medical examinations between 1971 and 2005. Mesothelioma and asbestosis mortality was defined by presence on the national Mesothelioma or Asbestosis Registers respectively. Mortality trends were examined by comparing mortality to December 2005 in workers attending their first medical before or after the ALR implementation, using Poisson regression models.

Results There were 15 557 deaths from all causes among 98 912 men and women to the end of 2005; of these 649 were listed on the Mesothelioma Register and 477 on the Asbestosis Register. In workers first exposed before 1983 and with less than 23 years occupational exposure to asbestos, mesothelioma and asbestosis mortality, adjusted for age, sex, cohort, job, and smoking status, increased with latency; there was no such trend in those first exposed after 1982. The divergence in mortality between the two groups appeared to increase with latency, but limited follow-up time in the post-ALR group means that the findings should be treated with caution.

Conclusions This study provides early indications of lower mesothelioma and asbestosis mortality among workers first exposed after implementation of the ALR. © Crown Copyright 2011