Browsing by Author "Simonato L"

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    Heirarchical regression for multiple comparisons in a case-control study of occupational risks for lung cancer.
    (Public Library of Science, 11/06/2012) Corbin M; Richiardi L; Vermeulen R; Kromhout H; Merletti F; Peters S; Simonato L; Steenland K; Pearce NE; Maule M
    Background Occupational studies often involve multiple comparisons and therefore suffer from false positive findings. Semi-Bayes adjustment methods have sometimes been used to address this issue. Hierarchical regression is a more general approach, including Semi-Bayes adjustment as a special case, that aims at improving the validity of standard maximum-likelihood estimates in the presence of multiple comparisons by incorporating similarities between the exposures of interest in a second-stage model. Methodology/Principal Findings We re-analysed data from an occupational case-control study of lung cancer, applying hierarchical regression. In the second-stage model, we included the exposure to three known lung carcinogens (asbestos, chromium and silica) for each occupation, under the assumption that occupations entailing similar carcinogenic exposures are associated with similar risks of lung cancer. Hierarchical regression estimates had smaller confidence intervals than maximum-likelihood estimates. The shrinkage toward the null was stronger for extreme, less stable estimates (e.g., “specialised farmers”: maximum-likelihood OR: 3.44, 95%CI 0.90–13.17; hierarchical regression OR: 1.53, 95%CI 0.63–3.68). Unlike Semi-Bayes adjustment toward the global mean, hierarchical regression did not shrink all the ORs towards the null (e.g., “Metal smelting, converting and refining furnacemen”: maximum-likelihood OR: 1.07, Semi-Bayes OR: 1.06, hierarchical regression OR: 1.26). Conclusions/Significance Hierarchical regression could be a valuable tool in occupational studies in which disease risk is estimated for a large amount of occupations when we have information available on the key carcinogenic exposures involved in each occupation. With the constant progress in exposure assessment methods in occupational settings and the availability of Job Exposure Matrices, it should become easier to apply this approach.
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    Occupation and risk of upper aerodigestive tract cancer: The ARCAGE study
    (Wiley Online, 15/05/2012) Richiardi L; Corbin M; Marron M; Ahrens W; Pohlabeln H; Lagiou P; Minaki P; Agudo A; Castellsague X; Slamova A; Schejbalova M; Kjaerheim K; Barzan L; Talamini R; MacFarlane GJ; MacFarlane TV; Canova C; Simonato L; Conway DI; McKinney PA; Sneddon L; Thomson P; Znaor A; Healy CM; McCartan BE; Benhamou S; Bouchardy C; Hashibe M; Brennan P; Merletti F
    We investigated the association between occupational history and upper aerodigestive tract (UADT) cancer risk in the ARCAGE European case-control study. The study included 1,851 patients with incident cancer of the oral cavity, oropharynx, hypopharynx, larynx or esophagus and 1,949 controls. We estimated odds ratios (OR) and 95% confidence intervals (CI) for ever employment in 283 occupations and 172 industries, adjusting for smoking and alcohol. Men (1,457 cases) and women (394 cases) were analyzed separately and we incorporated a semi-Bayes adjustment approach for multiple comparisons. Among men, we found increased risks for occupational categories previously reported to be associated with at least one type of UADT cancer, including painters (OR = 1.74, 95% CI: 1.01-3.00), bricklayers (1.58, 1.05-2.37), workers employed in the erection of roofs and frames (2.62, 1.08-6.36), reinforced concreters (3.46, 1.11-10.8), dockers (2.91, 1.05-8.05) and workers employed in the construction of roads (3.03, 1.23-7.46), general construction of buildings (1.44, 1.12-1.85) and cargo handling (2.60, 1.17-5.75). With the exception of the first three categories, risks both increased when restricting to long duration of employment and remained elevated after semi-Bayes adjustment. Increased risks were also found for loggers (3.56, 1.20-10.5) and cattle and dairy farming (3.60, 1.15-11.2). Among women, there was no clear evidence of increased risks of UADT cancer in association with occupations or industrial activities. This study provides evidence of an association between some occupational categories and UADT cancer risk among men. The most consistent findings, also supported by previous studies, were obtained for specific workers employed in the construction industry. © 2011 UICC.