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Keynote Session 2

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H. Checkoway.Department of Environmental & Occupational Health Sciences, University of Washington, Seattle, Washington, USA

The most common neurodegenerative disorders, Alzheimer’s disease (AD), Parkinson’s disease (PD), and amyotrophic lateral sclerosis (ALS), are substantial causes of morbidity and mortality throughout the world. Regrettably, very few aetiological factors have been identified for these disorders, although there is evidence from both toxicological and epidemiological research that environmental agents may play important causal roles. Notable examples are possible associations of aluminium with AD, pesticides with PD, and lead with ALS. Some of the environmental agents of concern are present in substantial quantities in the workplace, and thus it is quite appropriate to consider occupations as potential risk factors. To date, however, there are few convincingly established associations between occupational exposures and these neurodegenerative disorders. A partial explanation may be that, broadly speaking, the workplace is a minor aetiological contributor, perhaps overwhelmed in importance by genetic and lifestyle factors. Alternatively, it is quite plausible that occupational associations have gone undetected or have been underestimated because of some of the inherent difficulties in studying neurodegenerative diseases in occupational settings. Among the numerous challenges in identifying occupational risk factors, the following are especially prominent: (a) neurodegenerative diseases are relatively rare, compared with cardiovascular diseases or cancer; (b) these diseases typically occur at older ages, long after retirement; (c) diagnoses can be inaccurate, especially when based on mortality data; (d) there are few, if any, population based disease registries; and (e) exposure assessment can be problematic, particularly in community based case–control studies, which predominate in the literature. Approaches to improve epidemiological methodology, such as longitudinal studies of disease onset and progression among well characterised occupational cohorts, will be suggested.


H. Kromhout.Institute for Risk Assessment Sciences, Utrecht University, Utrecht, The Netherlands

Exposure assessors are being confronted with ever increasing demands from epidemiologists and indirectly risk assessors. Simple assessments of exposure status (exposed/non-exposed) or semi-quantitative approaches via job exposure matrices and/or expert judgement are no longer in vogue. As a consequence of this, more quantitative approaches in both industry based studies and studies of the general population are needed. At the same time, occupational hygienists are shying away from measurements as being the primary tool in their toolbox. Without future collection of measurements of occupational exposures, exposure assessors and epidemiologists will have a rather limited time period for conducting quantitative analyses of exposure response relations, unless the field becomes less dependent on occupational hygienists. This keynote will address the changes in the occupational and general environment that exposure assessors of today have to deal with. Examples of quantitative approaches in multicentre general population studies such as the European Community Respiratory Health Survey and quantitative approaches for industry based studies based on large multicountry exposure measurement databases will be presented. The focus will be on trends in frequency, intensity, and variability of occupational exposures and how the factors behind these trends should be incorporated in data driven approaches that will live up to the expectations of epidemiologists and risk assessors.

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