Occupational histories

A case control study by Salib and Hillier (1996) examined the possible relationship between the risk of Alzheimer s disease and occupational exposure to airborne aluminum. The occupation histories of patients with a clinical diagnosis of Alzheimer s disease (198 cases) were compared with two control groups patients with dementia other than Alzheimer s disease (164 cases) and patients with diagnoses other than dementia. Occupational histories were obtained from the patients via a questionnaire. No significant association between occupational exposure to aluminum dust or fumes and the risk of Alzheimer s disease were found (the odds ratio for the comparison with all controls was 0.98, 95% confidence interval of 0.53-1.75). 

Exposure Registries. Approximately 250 members were enrolled in the 2,3,7,8-TCDD Subregistry of the National Exposure Registry in 1991 (ATSDR 1996). These individuals were chosen because they participated in one or more of the Missouri Dioxin Health Studies and were reportedly exposed to CDDs at one of the four Times Beach, MO area CDD sites. Data collected for each member of the Dioxin Subregistry include demographic information, smoking and occupational histories, and self-reported... 

Weighting of Occupational Histories—If a worker has been employed in several occupations over a period of years, some measure of his total dust exposure becomes necessary. This is particularly true when medical findings must be correlated with the amount of the workers exposure. Pneumoconiosis is the result of prolonged exposure to dust, and... 

Table 80—Occupational History of a Feldspar Worker, 45 Years Old, Who Began Work at the Age of 15...

Table 81—Weighting of Exposure of Worker Whose Occupational History...

Errors in Quantitative Assessments Versus Variability 255 EXPERIENCE WITH EXPOSURE ASSESSMENT IN CASE-CONTROL STUDIES 259 Occupational Histories 260... 

The combination of the health-relevant time-window and the toxicokinetic properties of the agent of interest determine the optimal exposure assessment strategy. Dioxin, a contaminant of chlorophenoxy herbicides and fungicides, has a relatively long biological half-life, estimated at about seven years and is measurable in serum. Serum measurements of dioxin are therefore relatively stable, and simple first-order kinetics have been used to back-estimate serum dioxin levels on the basis of an occupational history. Such exposure data have been used quite successfully in epidemiological analyses of cohorts of pesticide producers (Hooiveld et al, 1998). 

The accuracy of exposure assessment is determined by systematic and random errors in the assessment. For quantitative exposure assessments, important sources of error include measurement errors (i.e. from laboratory and field monitoring techniques), as well as variations in exposure over time and space. For qualitative exposure proxies (e.g. self-reported past exposures, occupational histories or expert evaluations), the most important sources of error are recall bias (systematic differences in exposure recall between cases and controls) and random error, expressed in terms of intra- and inter-rater agreement. Although systematic errors can result in serious misinterpretations of the data, especially due to scaling problems, random errors have received more attention in epidemiology because this type of error is pervasive, and its effect is usually to diminish estimates of association between exposure and disease. The magnitude of random errors can be considerable in epidemiological field studies. 

Brisson, C., M. Vezina, P.M. Bernard and S. Gingras (1991). Validity of occupational histories obtained by interview with female workers. Am. J. Ind. Med., 19, 523-530. 

Rosenberg, C.R., M.N. Mulvihill, A. Fischbein and S. Blum (1987). An analysis of the validity of self-reported occupational histories using a cohort of workers exposed to PCBs, Br. J. Ind. Med., 44, 702-710. 

Warneryd, B., M. Thorslund and P. Ostlin (1991). The quality of retrospective questions about occupational history - a comparison between survey and census data, Scand. J. Soc. Med., 19, 7-13. 

The studies of Nishimoto et al. (1988), Yamada (1974) and Inada et al., (1978) provide strong evidence for a causal link between chemical agent exposure and cancer however, because the workers were exposed to multiple chemicals, it is not possible to state conclusively that the cancers were due solely to sulfur mustard. Furthermore, it should be noted that several possible confounding factors, such as tobacco smoking habits, preexisting health conditions, and post-exposure occupational histories of the workers, were not evaluated. In addition, SMRs themselves may not provide an accurate estimate of relative cancer risk if they do not correlate with tumor incidence rates in exposed and control groups (i.e., if social/economic or other differences between control and exposed groups result in differences in health care which affect survival rates). 

Katjalainen A, Anttila S, Heikkila L, et al. 1993a. Asbestos exposure among Finnish lung cancer patients Occupational history and fiber concentration in lung tissue. Am J Ind Med 23(3) 461-471. 

From prehistoric times, the human occupation of Amazonia has been concentrated along major transport avenues. For the greatest part of the basin s occupation history, these avenues were large rivers, which traverse and connect all parts of the basin along natural and free-flowing... 

Clinical history should include both medical and occupational history to determine a relationship between exposure to a specific substance and development of respiratory hypersensitivity. Relevant information includes aggravating factors both in the home and workplace, the onset and progress of the disease, family history and medical history of the patient in question. The medical history should also include a note of other allergic or airway disorders from childhood, and smoking history. 

Cohort Definition and Follow-Up Period A variety of sources of information are used to identify workers exposed to a particular workplace hazard, to construct an occupational history, and to complete the collection of information necessary for tracing (see below). It is essential that the cohort be well defined and that criteria for eligibility are strictly followed. This requires that a clear statement be made about membership of the cohort so that it is easy to decide whether an employee is a member or not. It is also important that the follow-up period be carefully defined. For instance, it is readily apparent that the follow-up period should not start before exposure has occurred. Furthermore, it is uncommon for the health effect of interest to manifest itself immediately after exposure, and allowance for an appropriate biological induction (or latency) period may need to be made when interpreting the data. 

Additional information besides the DSM-IV-TR diagnosis is required before a comprehensive treatment plan can be developed. The American Psychiatric Association Practice Guidelines for Psychiatric Evaluation of Adults offers a more comprehensive approach to patient assessment. It includes a full discussion of the domains needed for a thorough clinical evaluation, including chief complaint history of present illness past psychiatric history general medical history social, family, and occupational history physical and mental status examinations and diagnostic tests. It further describes issues of privacy, evaluations in the elderly, and techniques for working with multidisciplinary teams. ... 

The diagnosis of chemically induced respiratory disorders requires a careful occupational history (Bernstein, DI, 1993). A good history should try to establish an occupational relationship with the initiation of symptoms. For example, OA typically improves away from work and recurs upon reexposure. However, there are several instances where a history may fail to identify the relationship between respiratory symptoms and work (Bernstein, DI, 1993). For example, workers suspected of having OA may manifest primarily a LAR and therefore may not have symptoms until they are at home or away from work. Also if OA is very severe there may not be noticeable improvement of symptoms away from work (Bernstein, DI, 1993). 

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