Influence of exposure assessment and parameterization on exposure response. Aspects of epidemiologic cohort analysis using the Libby Amphibole asbestos worker cohort

• Published in: Journal of exposure science & environmental epidemiology 2015-01, Vol.25 (1), p.12-17
• Main Authors: Bateson, Thomas F, Kopylev, Leonid
• Format: Article
• Language: English
• Subjects: 692/699/67/1612; 692/700/3160; 692/700/478/174; 704/172; Adult; Amphiboles; Asbestos; Asbestos, Amphibole - adverse effects; Asbestos, Amphibole - analysis; Cohort analysis; Cohort Studies; Dose-response relationship (Biochemistry); Environmental aspects; Epidemiology; Error analysis; Evaluation; Exposure; Female; Health aspects; Health risk assessment; Health risks; Humans; Lung cancer; Lung Neoplasms - chemically induced; Lung Neoplasms - epidemiology; Lung Neoplasms - mortality; Male; Medicine; Medicine & Public Health; Mining - statistics & numerical data; Montana - epidemiology; Mortality; Mortality risk; Occupational exposure; Occupational Exposure - analysis; Occupational Exposure - statistics & numerical data; Occupational health; Occupational health and safety; original-article; Parameterization; Prognosis; Q factors; Risk factors; Smoking - adverse effects; Smoking - epidemiology; Statistical methods
• ISSN: 1559-0631; 1559-064X
• DOI: 10.1038/jes.2014.3

Recent meta-analyses of occupational epidemiology studies identified two important exposure data quality factors in predicting summary effect measures for asbestos-associated lung cancer mortality risk: sufficiency of job history data and percent coverage of work history by measured exposures. The objective was to evaluate different exposure parameterizations suggested in the asbestos literature using the Libby, MT asbestos worker cohort and to evaluate influences of exposure measurement error caused by historically estimated exposure data on lung cancer risks. Focusing on workers hired after 1959, when job histories were well-known and occupational exposures were predominantly based on measured exposures (85% coverage), we found that cumulative exposure alone, and with allowance of exponential decay, fit lung cancer mortality data similarly. Residence-time-weighted metrics did not fit well. Compared with previous analyses based on the whole cohort of Libby workers hired after 1935, when job histories were less well-known and exposures less frequently measured (47% coverage), our analyses based on higher quality exposure data yielded an effect size as much as 3.6 times higher. Future occupational cohort studies should continue to refine retrospective exposure assessment methods, consider multiple exposure metrics, and explore new methods of maintaining statistical power while minimizing exposure measurement error.