Mortality among British asbestos workers undergoing regular medical examinations (1971-2005)

Anne-Helen Harding ^1*, Andrew Darnton ², Johannah Wegerdt ¹ and Damien McElvenny ³

¹ Health & Safety Laboratory, United Kingdom
² Health & Safety Executive, United Kingdom
³ University of Central Lancashire, United Kingdom

^* To whom correspondence should be addressed. E-mail: anne-helen.harding{at}hsl.gov.uk.

Accepted 7 February 2009

Abstract

Objectives: The Great Britain Asbestos Survey was established to monitor mortality among workers covered by regulations to control occupational exposure to asbestos. This study updates the estimated burden of asbestos-related mortality in the cohort, and identifies risk factors associated with mortality.

Methods: From 1971, workers were recruited during initially voluntary and later statutory medical examinations. A brief questionnaire was completed during the medical, and participants were flagged for death registrations. Standardised Mortality Ratios (SMRs) and Proportional Mortality Ratios (PMRs) were calculated for deaths occurring before 2006. Poisson regression analyses were undertaken for diseases with significant excess mortality.

Results: There were 15,496 deaths among 98,117 workers followed-up for 1,779,580 person-years. The SMR for all cause mortality was 141 (95% CI 139-143) and for all malignant neoplasms 163 (95% CI 159-167). The SMRs for cancers of the stomach (166), lung (187), peritoneum (3,730), and pleura (968), mesothelioma (513), cerebrovascular disease (164) and asbestosis (5,594) were statistically significantly elevated, as were the corresponding PMRs. In age- and sex-adjusted analysis, birth cohort, age at first exposure, year of first exposure, duration of exposure, latency, and job type were associated with the relative risk of lung, pleural, and peritoneal cancers, asbestosis and mesothelioma mortality.

Conclusions: Known associations between asbestos exposure and mortality from lung, peritoneal, and pleural cancers, mesothelioma, and asbestosis were confirmed, and evidence of associations with stroke and stomach cancer mortality was observed. Limited evidence suggested that the asbestos-related disease risk may be lower among those first exposed in more recent times.