Occupational exposure assessment in the general population: improvements, innovations, and impact

Abstract

Chapter 1 | General Introduction 1 there is an added benefit of being able to include more cases in the study, which allows the study of rare diseases, disease subtypes or uncommon pre-clinical conditions as health endpoints. Due to large sample sizes, population-based studies are well suited to investigate more complex issues surrounding exposure and disease, such as the effect of confounding and interactions between multiple exposures, as well as the exploration of novel exposure-disease associations.Naturally, population-based studies are not without disadvantages. One of the most significant limitations is the difficulty in assessing occupational exposure in population-based studies, as exposure may originate from a variety of workplaces and different time periods. If population-based studies are unable to accurately quantify disease risks associated with a unit of exposure, their utility and impact become limited in risk assessment and policymaking. The following chapters in this thesis aim to review, explore, and discuss potential means of improving exposure assessment and disease risk quantification in population-based studies.Chapter 2 is a systematic literature review on occupational exposure assessment approaches used in population-based case-control studies on carcinogens in the previous four decades. The review explores the reliability performance of assessment approaches and highlights important areas of new development.Chapter 3 demonstrates the performance of a real-time, algorithmic approach in assigning flexible, modular questionnaires during work history interviews in order to gather exposure information related to specific tasks. The manuscript covered the evaluation of a set of interview algorithms applied in 11,409 jobs episodes from subjects from the AsiaLymph project, which is a large, multi-centered hospital-based case-control study on lymphoma and leukemia in Asia.Chapter 4 describes the procedure, training, and coordination employed to complete the occupational coding for 34,353 jobs from 12,590 subjects in the AsiaLymph project and assesses the reliability performance in job coding work performed by different coders. The reliability performance of exposure assessment resulting from the different sets of job codes is further explored for different exposures via a generic job-exposure matrix.Chapter 5 estimates the association between occupational benzene exposure and risks of lymphohaematopoietic cancers in the Swiss National Cohort, which is a censusbased cohort of 2.97 million Swiss citizens with 13,415 lymphohaematopoietic cancer cases. The study serves to demonstrate that registry-based cohorts in the general population can be useful for investigating the relationships between workplace exposures and human diseases, particularly for rare disease subtypes.