Attributable risk in men in two French case-control studies on mesothelioma and asbestos

Abstract

Pleural mesothelioma is a primary tumor of the pleura that is mainly due to asbestos exposure. To study the relationship between mesothelioma and occupational asbestos exposure in France, two case-control studies (A and B) were conducted. A substantial difference in the attributable risk in the population (AR p ) was observed among men: 44.5% (95% CI: [32.6 -56.4]) in study .6]) in study B. As different exposure assessment expert methods were used, the main objective of this work was to re-estimate the ARp among men in two case-control studies according to a common standardized exposure assessment by using a Job Exposure Matrix (JEM) and to assess the role of subjects" selection. The initial observed AR p difference was maintained:36.3% (95% CI: [24.3 -50.3]) in study A and 69.7% (95% CI: 51.7 -83.2]) in study B. Further investigations highlighted the potential selection bias introduced in both studies, especially among controls. The AR p could be underestimated in study A and overestimated in study B. After weighting subjects according to distribution of socio-economic status in the general population for controls and according to distribution of socio-economic status of cases registered by the French National Mesothelioma Surveillance Program, re-estimated AR p values were 52.4% in study A and 70.2% in study B. These results provide additional information to describe the relationship between pleural mesothelioma and occupational asbestos exposure, but also confirm the importance of subjects" recruitment in case control studies, particularly control selection. KEY WORDSAsbestos, attributable risk, case-control study, men, mesothelioma, occupational exposure.

Hand‐spinning chrysotile exposure and risk of malignant mesothelioma: A case–control study in Southeastern China

“…We found a dose–response relationship between probability, intensity, and frequency of exposure, exposure duration and risk of mesothelioma, consistent with previous study; we also observed a dose–response relationship between CEI and risk of mesothelioma, in line with other studies . Taken together, our findings suggest that chrysotile exposure is the main cause of mesothelioma in Southeast China.…”

“…We found a dose-response relationship between probability, intensity, and frequency of exposure, exposure duration and risk of mesothelioma, consistent with previous study 40 ; we also observed a dose-response relationship between CEI and risk of mesothelioma, in line with other studies. 35,41 Taken Rounding off for numbers above 10. OR: odds ratio matched for age, gender and region; CI: confidence interval; "f/mL-years": fibers per milliliter years, based on the assessment of experts' subjectivity.…”

“…The parameters of probability, intensity and frequency were further transformed into likelihood, estimated concentrations and percent of work time with asbestos exposure, respectively . CEI, expressed as “fibers per milliliter years (f/mL‐years)”, was a semi‐quantitative index calculated by the sum of the products of probability, frequency, intensity and duration of each job exposure . Additionally, the duration of jobs with asbestos exposure were also calculated .…”

“…32,34 CEI, expressed as "fibers per milliliter years (f/mL-years)", was a semiquantitative index calculated by the sum of the products of probability, frequency, intensity and duration of each job exposure. 35 Additionally, the duration of jobs with asbestos exposure were also calculated. 36,37 Weights for each category of those parameters were assigned using the approach proposed by others.…”

Occupational risk factors have to be considered in the definition of high-risk lung cancer populations

“…For asbestos, one can compare the observed 52% exposure prevalence among controls to a 54–68% of possibly asbestos-exposed controls in a recent mesothelioma case–control study (Lacourt et al , 2010) (although their definition included also possible exposure to asbestos). The high asbestos exposure prevalence is also confirmed by the high pleural mesothelioma rates (see online appendix).…”