Multiple Chemical Sensitivity

Multiple Chemical Sensitivity (MCS), a condition also known as Chemical Sensitivity (CS), Chemical Intolerance (CI), Idiopathic Environmental Illness (IEI) and Toxicant Induced Loss of Tolerance (TILT), is an acquired multifactorial syndrome characterized by a recurrent set of debilitating symptoms. The symptoms of this controversial disorder are reported to be induced by environmental chemicals at doses far below those usually harmful to most persons. They involve a large spectrum of organ systems and typically disappear when the environmental chemicals are removed. However, no clear link has emerged among self-reported MCS symptoms and widely accepted objective measures of physiological dysfunction, and no clear dose-response relationship between exposure and symptom reactions has been observed. In addition, the underlying etiology and pathogenic processes of the disorder remain unknown and disputed, although biologic and psychologic hypotheses abound. It is currently debated whether MCS should be considered a clinical entity at all. Nevertheless, in the last few decades MCS has received considerable scientific and governmental attention in light of the many persons reporting this illness. In this review, we provide a general overview of the history, definition, demographics, prevalence, and etiologic challenges in defining and understanding MCS.

Time-Dependent Sensitization in Animals: A Possible Model of Multiple Chemical Sensitivity in Humans

It of ten happens in science that clues to the nature of a problem under study come from a completely different, seemingly unrelated, line of investigation. This may be the case with MCS and Time-Dependent Sensitization (TDS), a phenomenon we discovered in rats in the late 1970s and later named. TDS refers to the ability of mild stressors whether pharmacological or environmental to induce physiological and behavioral effects which then progress, i.e., get stronger, entirely as a function of the passage of time since stressor presentation. This strengthening is revealed when the organism is later exposed to either the original or another stressor. The characteristics of TDS bear a remarkable resemblance to the features of MCS and that similarity is the subject of this manuscript.

White Paper: Chemical Sensitivity: History and Phenomenology

Nearly everyone has heard something about chemical sensitivity, either from personal experience with someone who has the condition or from the media. The television series Northern Exposure recently featured a chemically sensitive attorney who lived in a geodesic dome in Alaska, and L.A. Law depicted the struggles of a Persian Gulf veteran with chemical sensitivities who lost his case against the Veterans Administration, but may appeal later in the season. Television news programs and the printed media have showcased patients living spartan existences in remote areas or in aluminum foil-lined rooms. Our views of the illness no doubt are colored by our own personal experiences of it. While some discount or make jokes about chemical sensitivity or these patients, physicians who have seen a number of them are discovering that many appear to be credible individuals with prior good work records who say they became ill following an identifiable exposure to chemicals.

Multiple Chemical Sensitivity, Culture and Delegitimization: A Feminist Analysis

The condition referred to as multiple chemical sensitivity (MCS), chemical injury (CI), environmental illness (El), 20th-century disease or toxic encephalopathy has generated controversy because victims' claims of harm from low levels of chemicals in the environment conflict with general mainstream belief in the safety of these substances. Mainstream (western) culture's response to persons with MCSICI has interacted with sexism, served to delegitimize victims thereby reducing their power, reduced the victim's context (because of forced isolation), and jeopardized jobs and relationships. This article will analyze the situation of the chemically injured person and culture's response from a feminist perspective, and discuss cultural delegitimization as a process used by a chemical culture to neutralize the message of the person with MCSICI, i.e., that the environment is unsafe for her/him, and, by extension, for others.

[Pathophysiology of multiple chemical sensitivity]

INTRODUCTION AND BACKGROUND

Multiple chemical sensitivity (MCS) is a complex clinical entity that includes a large number of non-specific symptoms, associated in a univocal manner in each patient and triggered by exposure to various chemicals at low concentrations, well below those known to cause toxic effects. However, no objective test exists currently to diagnose this syndrome. One of the main reasons is that the pathophysiology is poorly understood. However, many explanatory hypotheses have been proposed.

VIEWPOINTS AND CONCLUSIONS

Patients with symptoms of MCS are often encountered by pulmonologists. Their suffering is undeniable but, unfortunately, the lack of understanding of the pathophysiological mechanisms makes treatment difficult and empirical.

Two weeks of permanence in negatively-charged air conditions causes alteration of natural killer cell function

The effects of negatively-charged air conditions were analyzed as one of the approaches to improve health and quality of life. We previously reported that the use of a charcoal coating and application of an electric voltage yielded predominantly negatively-charged particles in an experimental room, and that 2.5 hours of living in these conditions caused a slight activation of the immune system (slight elevation of serum interleukin (IL)-2), regulated blood flow, and stabilized the autonomic nervous system when compared with control conditions (no dominance of negatively-charged particles). In this study, we expanded the previous study and placed 15 subjects in negatively-charged air conditions for two weeks during the night and analyzed various biological parameters. Although individual biological reactions differed from subject to subject, natural killer (NK) cell activity increased significantly following living in negatively-charged air conditions. Taken together, the results of the previous investigation and those of this study show that repeated elevation of IL-2 (although it immediately returned to the baseline level) causes chronic and recurrent stimulation to NK cells and results in the steady activation of NK cells. Negatively-charged air particles may be a good tool to improve health and quality of life.

Sequence variations in subjects with self-reported multiple chemical sensitivity (sMCS): a case-control study

Polymorphisms in several genes contribute to interindividual differences in the metabolism of xenobiotics, and may lead to toxicity and disease. The balance between activation and/or detoxification processes may influence an individual's susceptibility to disease. One postulated mechanism underlying multiple chemical sensitivity (MCS) is based on increased metabolism of xenobiotics. The aim of the present study was to determine such polymorphisms in cases with self-reported MCS (sMCS) and controls. sMCS cases (14 men, 45 women, mean age: 48 yr) and controls (14 men, 26 women, mean age: 44 yr) of the same anthroposphere were characterized using the MCS-questionnaire from Huppe and coworkers (2000) and a standardized questionnaire for living conditions and living factors. Allelic frequencies of genomic variations for 5HTT, NAT1, NAT2, PON1, PON2, and SOD2 were determined. The MCS questionnaire from Huppe et al. (2000) differentiated between cases and controls with 87.5% sensitivity and 90% specificity. Compared to controls the sMCS cases had lower exposures, especially to odorous factors, and worse social conditions. No significant differences of the allelic distribution of genetic polymorphisms in the genes for 5HTT, NAT1, NAT2, PON1, PON2, and SOD2 were found between cases and controls. The results are in contrast to the study of McKeown-Eyssen and coworkers (2004) but in accordance with the German MCS multicenter study. Although the MCS questionnaire from Huppe et al. (2000) allowed us to differentiate sMCS cases and controls, it was not strong enough for a discrimination based on sequence variations in genes for enzymes involved in xenobiotic metabolism. Therefore, further research needs to focus on a unique phenomenological characterization of MCS.

Environmental sensitivity

The concept of environmental sensitivity is popular among a small group of physicians who believe that exposure to low levels of numerous environmental chemicals can cause a disease with numerous symptoms but no objective physical or laboratory abnormalities. The condition lacks a clear definition. Numerous theories that have been offered to explain the condition encompass immunotoxic, allergic, autoimmune, neurotoxic, cytotoxic, metabolic, behavioral, psychiatric, iatrogenic, and sociologic mechanisms. Environmental sensitivity has many features in common with other controversial syndromes, such as the chronic fatigue syndrome. Patients with environmental sensitivity frequently are subjected to unproven and unnecessary diagnostic tests and therapeutic modalities. In spite of the lack of physical illness and absence of pathology, patients often experience extreme disability, because their symptoms are triggered by common environmental exposures. The phenomenon of environmental sensitivity needs to be evaluated critically using scientifically sound methods. The practice of clinical ecology encompasses the practices of environmental sensitivity and its theories. Most methods of diagnosis and treatment have been disproved, and the concepts underlying these theories are not scientific. Alternative means of diagnosis and management are presented.

Environmental sensitivities: prevalence of major symptoms in a referral center: the Nova Scotia Environmental Sensitivities Research Center Study

Although the phenomenon of environmental sensitivities (ES) has no clear etiology nor well-accepted pathophysiology, affected individuals experience symptoms that cause varying levels of dysfunction. Through a dedicated, government-funded research and treatment center, a detailed questionnaire covering 217 symptoms in 13 systems was mailed in 1997-1998 to 812 individuals referred to the center by physicians. A total of 385 (47%) questionnaires were returned, and data were analyzed on 351 individuals. Participants tended to be women (80%), middle-aged individuals (37% age 40-49 years), and those in higher educational groups (28% completed university), but there was wide variation in demographic variables. General symptoms such as difficulty concentrating, fatigue, forgetfulness, and irritability dominated the overall prevalence of symptoms since the start of their illness. Those related to irritation such as sneezing, itchy or burning eyes, and hoarseness or loss of voice were more common after exposure to environmental irritants. Ranking of symptoms using severity scores was consistent between men and women. Overall scores were higher in women, in participants who were separated or divorced, and in low-income groups. The type and consistency of symptoms experienced after exposure to triggering substances may not fit a purely psychogenic theory.

Applied epidemiology and environmental health: emerging controversies

This review article assesses the state of the science in environmental epidemiology, not by summarizing current scientific findings but rather by examining conceptual controversies in the study of how environmental factors influence human health. This approach seems necessary because environmental epidemiology presently stands at a crossroads-in fact, at a number of overlapping crossroads. The field teems with epistemologic debates concerning appropriate paradigms for framing research questions, interpreting data, and applying research findings to policy. The present review focuses on emerging controversies related to three questions: What is considered "environmental"? What counts as credible research in environmental epidemiology? And what does "applied epidemiology" mean in the context of environmental health? The goal is to organize the presently fragmented critical literature on these issues and to promote productive dialogue by identifying central themes in current conceptual debates.

Patients with multiple chemical sensitivities in an occupational health clinic: presentation and follow-up

Thirty-five people with work-related Multiple Chemical Sensitivities were studied to learn about the onset and progression of illness. The subjects were selected from patients at an occupational health clinic. Individuals were identified as subjects if they fulfilled a seven-point case definition for Multiple Chemical Sensitivities and if onset of symptoms was related to workplace exposures. Three occupational exposures to solvents, poor indoor-air quality, and remodeling were associated with onset of Multiple Chemical Sensitivities in 63% of the subjects. Symptoms indicative of a nervous-system disorder topped the list of the most frequently reported symptoms. Commonalities in exposures and symptoms suggest that Multiple Chemical Sensitivities represents a distinct diagnostic category. Even with an incomplete understanding of etiology, it may be possible to limit the onset of work-related Multiple Chemical Sensitivities.