RT Journal Article SR Electronic T1 Asbestos fibre dimensions and lung cancer mortality among workers exposed to chrysotile JF Occupational and Environmental Medicine JO Occup Environ Med FD BMJ Publishing Group Ltd SP 580 OP 584 DO 10.1136/oem.2009.050120 VO 67 IS 9 A1 Dana Loomis A1 John Dement A1 David Richardson A1 Susanne Wolf YR 2010 UL http://oem.bmj.com/content/67/9/580.abstract AB Objectives To estimate exposures to asbestos fibres of specific sizes among asbestos textile manufacturing workers exposed to chrysotile using data from transmission electron microscopy (TEM) and to evaluate the extent to which the risk of lung cancer varies with fibre length and diameter.Methods 3803 workers employed for at least 1 day between 1 January 1950 and 31 December 1973 in any of three plants in North Carolina, USA that produced asbestos textile products and followed for vital status through 31 December 2003 were included. Historical exposures to asbestos fibres were estimated from work histories and 3578 industrial hygiene measurements taken in 1935–1986. Exposure–response relationships for lung cancer were examined within the cohort using Poisson regression.Results Indicators of fibre length and diameter obtained by TEM were positively and significantly associated with increasing risk of lung cancer. Exposures to longer and thinner fibres tended to be most strongly associated with lung cancer, and models for these fibres fit the data best. Simultaneously modelling indicators of cumulative mean fibre length and diameter yielded a positive coefficient for fibre length and a negative coefficient for fibre diameter.Conclusions The results support the hypothesis that the risk of lung cancer among workers exposed to chrysotile asbestos increases with exposure to longer fibres. More research is needed to improve the characterisation of exposures by fibre size and number and to analyse the associated risks in a variety of industries and populations.