Multiple Chemical Sensitivities: Addendum to Biologic Markers in Immunotoxicology (1992)
Chapter: Research Protocol for Clinical Evaluation
OVERVIEW
To develop a research agenda on multiple chemical sensitivity syndrome, participants were assigned to three multi-disciplinary groups. The groups were asked to focus on: 1) the design of a research protocol for clinical evaluation; 2) studies to evaluate relevant exposures and mechanisms; and 3) epidemiologic approaches. The specific charges were:
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Development of a Working Definition for the Syndrome
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Evaluation of All Potential Causes
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Evaluation of Uncertainties Associated with the Data and Data Gaps
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Preparation of Report on Research Recommendations and Protocol
The reports of the three working groups follow. Because consensus was achieved within each group on the substance and language of the recommendations, the reports are presented unedited, as accepted at the workshop.
Research Protocol for Clinical Evaluation
WORKING GROUP I
The group agreed that patients have been identified with a condition of multiple and often diverse symptoms that have been attributed to chemical agents in the environment. These patients may have recognized disease syndromes. However, symptomatology related to multiple chemicals is a distinct feature of these patients that is not classifiable by existing criteria used in conventional medical practice for psychiatric or physical illness. Thus, this feature cannot be uniquely coded in either DSM-III-R or ICD-9.
CASE CRITERIA
Criteria for the selection of cases for evaluation of multiple chemical sensitivity were discussed, and the committee agreed on criteria for research purposes as discussed below (definitions for other purposes were not addressed by this group):
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Sensitivity to chemicals. By sensitivity we mean symptoms or signs related to chemical exposures at levels tolerated by the population at large that is distinct from such well recognized hypersensitivity phenomena as IgE-mediated immediate hypersensitivity reactions, contact dermatitis, and hypersensitivity pneumonitis.
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Sensitivity may be expressed as symptoms and signs in one or more organ systems.
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Symptoms and signs wax and wane with exposures. It is not necessary to identify a chemical exposure associated with the onset of the condition. Preexistent or concurrent conditions, e.g. asthma, arthritis, somatization disorder or depression, should not exclude patients from consideration.
CANDIDATE POPULATIONS
The selection of subjects for research protocols will depend on the specific hypotheses to be tested. Identifiable populations include but are not restricted to:
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Symptom or sign based: Patients with reactivity to environmental chemicals, either through serf-reporting or meeting case selection criteria.
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Disease based: Patients with specific diseases that are suspected to be caused by or exacerbated by chemical exposures.
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Exposure based: Groups characterized by a common exposure, such as workers at a specific factory, occupants of a particular building, or residents of a contaminated community.
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Population based: Groups such as school children or a random community sample.
Appropriate comparison groups should be chosen in each case.
EVALUATION
Research design and methods should be chosen as appropriate for each hypothesis. However, a minimum uniform data base across these groups needs to be developed which shall include the items in Table One. Specialized evaluations need to be developed for investigating specific hypotheses as listed in Table Two. It is beyond the scope of this committee to develop these in detail.
A research priority will be the study of the adaptation-deadaptation hypothesis, and this study must be conducted at an early stage because the outcome of this investigation will influence future study design. An environmental control unit, a clinical research unit in which subjects are housed for the control of exposures to foods and chemicals, should be developed to study the adaptation-deadaptation hypothesis. Other possible uses of units would include control of exposures and challenging subjects ha a well-defined environment. Use of this modality will be very complex, and its indications and use must be researched and tested in detail. Other modalities of testing such as challenge chamber studies will have utility, and also must be studied in detail.
Prospective longitudinal studies of exposure based events are very important and should be performed.
TABLE 1
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Uniform Core Database |
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history of sensitivity to foods, chemicals, and drugs |
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age |
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gender |
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marital status |
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race |
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education |
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dietary history |
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socioeconomic status |
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standardized medical evaluation |
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occupational history |
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environmental and exposure history |
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smoking history |
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medication history |
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alcohol and drug use history |
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psychological screening |
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atopy |
TABLE 2
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Specialized Evaluations |
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Nutritional assessment |
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Metabolic phenotype |
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Psychological profile |
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Neuropsychological profile |
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Assessment of cell-mediated immunity |
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HLA haplotype |
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Provocative challenge |
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Bronchial hyperreactivity |
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Autonomic tone |
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Other immunological assessment |
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Other neurological assessment |
