The latency period of mesothelioma among a cohort of British asbestos workers (1978–2005)

BACKGROUND: The Great Britain (GB) Asbestos Survey is a prospective cohort of asbestos workers in GB. The objective of this study was to investigate determinants of mesothelioma latency, paying particular attention to indicators of intensity of asbestos exposure such as occupation, sex, and presence of asbestosis. METHODS: The analysis included members of the cohort who died with mesothelioma between 1978 and 2005. The primary outcome was the latency period defined as the time from first occupational exposure to asbestos to death with mesothelioma. Generalised gamma accelerated failure-time models were used to estimate time ratios (TRs). RESULTS: After excluding missing data, there were 614 workers who died with mesothelioma between 1978 and 2005. Total follow-up time was 9280 person-years, with a median latency of 22.8 years (95% confidence interval (CI) 16.0–27.2 years). In the fully adjusted model, latency was around 29% longer for females compared with males (TR=1.29, 95% CI=1.18–1.42), and 5% shorter for those who died with asbestosis compared with those who did not (TR=0.95, 95% CI=0.91–0.99). There was no evidence of an association between latency and occupation. CONCLUSION: This study did not find sufficient evidence that greater intensity asbestos exposures would lead to shorter mesothelioma latencies.