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A hierarchical Bayesian model for a variability analysis of measurements of occupational n-hexane exposure in ItalyDepartment of Statistics G. Parenti, University of Florence, Florence, Italy, toti{at}ds.unifi.it
Department of Statistics G. Parenti, University of Florence, Florence, Italy, Biostatistics Unit, CSPO, Florence, Italy
SA di Epidemiologia, ASF, Florence, Italy This study evaluates changes over time in occupational exposure to n-hexane by longitudinal repeated measurements analysis of data from the Biological Monitoring Registry from 1991 to 1998. The main sources of variability in n-hexane exposure among manufacturing workers in Florence province (Italy) are inspected. The 2,5-hexanedione concentrations in urine of industrial workers are explained by structural, individual and factory information. Here we analyse the effectiveness of a 1994 law on workplace conditions based on variability decomposition of measured 2,5-hexanedione concentrations. We propose a hierarchical Bayesian model which takes into account the different levels of aggregation of data. The results show that for leather and shoe factories, the within-subject and within-factory variance components remain the most important over the time of study, whereas the between-factory components decreased in accordance with the expected effect of the new legislation.
Key Words: hierarchical Bayesian model measurements variability occupational exposure
Statistical Modelling, Vol. 6, No. 2,
175-185 (2006) |
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