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

Multiple Chemical Sensitivity: It's time to catch up to the science

Multiple chemical sensitivity (MCS) is a complex medical condition associated with low dose chemical exposures. MCS is characterized by diverse features and common comorbidities, including fibromyalgia, cough hypersensitivity, asthma, and migraine, and stress/anxiety, with which the syndrome shares numerous neurobiological processes and altered functioning within diverse brain regions. Predictive factors linked to MCS comprise genetic influences, gene-environment interactions, oxidative stress, systemic inflammation, cell dysfunction, and psychosocial influences. The development of MCS may be attributed to the sensitization of transient receptor potential (TRP) receptors, notably TRPV1 and TRPA1. Capsaicin inhalation challenge studies demonstrated that TRPV1 sensitization is manifested in MCS, and functional brain imaging studies revealed that TRPV1 and TRPA1 agonists promote brain-region specific neuronal variations. Unfortunately, MCS has often been inappropriately viewed as stemming exclusively from psychological disturbances, which has fostered patients being stigmatized and ostracized, and often being denied accommodation for their disability. Evidence-based education is essential to provide appropriate support and advocacy. Greater recognition of receptor-mediated biological mechanisms should be incorporated in laws, and regulation of environmental exposures.

Neurological susceptibility to environmental exposures: pathophysiological mechanisms in neurodegeneration and multiple chemical sensitivity

The World Health Organization lists air pollution as one of the top five risks for developing chronic non-communicable disease, joining tobacco use, harmful use of alcohol, unhealthy diets and physical inactivity. This review focuses on how host defense mechanisms against adverse airborne exposures relate to the probable interacting and overlapping pathophysiological features of neurodegeneration and multiple chemical sensitivity. Significant long-term airborne exposures can contribute to oxidative stress, systemic inflammation, transient receptor subfamily vanilloid 1 (TRPV1) and subfamily ankyrin 1 (TRPA1) upregulation and sensitization, with impacts on olfactory and trigeminal nerve function, and eventual loss of brain mass. The potential for neurologic dysfunction, including decreased cognition, chronic pain and central sensitization related to airborne contaminants, can be magnified by genetic polymorphisms that result in less effective detoxification. Onset of neurodegenerative disorders is subtle, with early loss of brain mass and loss of sense of smell. Onset of MCS may be gradual following long-term low dose airborne exposures, or acute following a recognizable exposure. Upregulation of chemosensitive TRPV1 and TRPA1 polymodal receptors has been observed in patients with neurodegeneration, and chemically sensitive individuals with asthma, migraine and MCS. In people with chemical sensitivity, these receptors are also sensitized, which is defined as a reduction in the threshold and an increase in the magnitude of a response to noxious stimulation. There is likely damage to the olfactory system in neurodegeneration and trigeminal nerve hypersensitivity in MCS, with different effects on olfactory processing. The associations of low vitamin D levels and protein kinase activity seen in neurodegeneration have not been studied in MCS. Table 2 presents a summary of neurodegeneration and MCS, comparing 16 distinctive genetic, pathophysiological and clinical features associated with air pollution exposures. There is significant overlap, suggesting potential comorbidity. Canadian Health Measures Survey data indicates an overlap between neurodegeneration and MCS (p < 0.05) that suggests comorbidity, but the extent of increased susceptibility to the other condition is not established. Nevertheless, the pathways to the development of these conditions likely involve TRPV1 and TRPA1 receptors, and so it is hypothesized that manifestation of neurodegeneration and/or MCS and possibly why there is divergence may be influenced by polymorphisms of these receptors, among other factors.

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.

An Unusual Case of Multiple Food Allergies Comorbid with Multiple Chemical Sensitivity: A Case Report

Purpose

To report the case of a patient with multiple food allergies comorbid with multiple chemical sensitivity (MCS) who was misdiagnosed on various occasions, resulting in a negative impact on the patient's personal and social life.

Case Report

We present the case of a 43-year-old Colombian women with multiple food allergies concomitant with MCS. Symptoms started with a mild reaction to insecticides, car exhaust smoke, and perfumes and gradually evolved into a severe reaction to her environment. She also presented recurrent episodes of clinical reactivity to foods and persistent elevated IgE levels, as well as several life-threatening anaphylactic reactions. Alternative and allopathic therapies were applied, but her symptoms persisted. Various diagnoses were made before the definitive diagnosis.

Conclusion

MCS is an unusual entity of unknown pathophysiology that can, on rare occasions, coexist with food allergies. Early recognition and multidisciplinary treatment are required as these entities have a major impact on the patient's quality of life. We present the first Latin American case regarding the association of the two diseases.

[Multiple Chemical Sensitivity (MCS): History, Epidemiology and Mechanism]

Multiple chemical sensitivity (MCS), also known as idiopathic environmental intolerance, has been described as a chronic acquired disorder characterized by nonspecific symptoms in multiple organ systems and is associated with exposure to low-level chemicals. The name was established by Cullen, in 1987, although the name and diagnostic criteria are still under debate even now. A number of hypotheses concering the etiology and pathogenesis of MCS have been proposed, including impairmens of neurological, immunological and psychological systems. However, research on the possible mechanisms underlying MCS is far from complete. The name and diagnostic criteria of its history as well as theoretical and experimental mechanisms underlying MCS are reviewed here.

Profile of Patients with Chemical Injury and Sensitivity, Part II

Exposures which can induce multiple chemical sensitivity (MCS) involve symptomatic, usually repeated, exposures to pesticides, solvents, combustion products, remodeling, sick buildings, carbonless copy paper (occupational heavy use) and other irritants and petrochemicals. Accompanying toxic injury often involves the immune, endocrine and nervous systems as well as impairments in detoxification, energy and neurotransmitter metabolism, protein, mineral, and other nutrient deficiencies and gastrointestinal changes such as Candida, parasites, reduced chymotrypsin (marker enzyme for reduced pancreatic enzyme function), gluten intolerance, and reduced Secretory IgA. Chronic cortisol elevation leading to adrenal insufficiency if not corrected is common. Such elevation can lead to protein and mineral deficiencies with increased osteoporosis and reduced steroid precursors for normal estrogen and testosterone production. Detoxification changes often involve reduction in one or more Phase II pathways which causes excess free radical production. Impaired digestive enzymes can reduce breakdown of foods, with larger more antigenic molecules being absorbed and consequent food intolerances. Many of these conditions are treatable. There is extensive overlap of MCS with Chronic Fatigue Syndrome and Fibromyalgia which may be one condition in many cases. Current occupational exposure limits are not health based and thus may not prevent MCS and are totally inadequate to accommodate sensitive persons. Warning symptoms indicating increased risk for MCS onset include repeated headache, eye and respiratory irritation and fatigue. Eliminating exposures which cause repeated symptoms is a critical strategy for preventing sensitization and MCS. It also significantly reduces the degree of disability in persons with MCS, the single most important factor from the literature. Affected persons with disability can utilize the Americans With Disability Act to request reasonable accommodations for work, home (condo, apartment), and school.

Negative affect is associated with development and persistence of chemical intolerance: a prospective population-based study

OBJECTIVE

Chemical intolerance (CI) is characterised by negative health effects attributed to a heightened responsiveness to common airborne chemicals. This longitudinal study explored the hypothesised role of negative affect in the development and persistence of CI in a general population.

METHODS

A general population sample aged 19 to 72 years was examined in 2006-2008 and again in 2011-2012. Longitudinal data on CI were analysed with the purpose of examining baseline negative affect as a risk factor for having developed CI at 5-year follow-up and for reporting persistent CI. Participants were classified as reporting no signs of CI, having symptoms of CI and as being a likely CI case based on self-reported reactions to 11 common chemical exposures, symptoms related to chemical exposures and daily life adjustments attributed to reactions when exposed to chemicals.

RESULTS

A total of 69.4% of the participants who had reported CI at baseline also reported CI at follow-up. In participants with no baseline CI, 15.5% reported CI at follow-up and 18.1% reported symptoms related to chemicals but no daily life adjustments. Baseline negative affect was positively and statistically significantly associated with both development and persistence of CI.

CONCLUSIONS

Initial reports of CI were found to be persistent over time, and a considerable proportion of the participants with no CI at baseline reported having developed CI after 5 years. The positive association between negative affect and CI at the 5-year follow-up supports negative affect as a possible risk factor for CI.

Unmet health care needs for persons with environmental sensitivity

Studies of unmet health care needs have shown that women, people with poor health, and people with lower socioeconomic status are more likely to report having unmet health care needs. In this study, we examined the types of and reasons for unmet health care needs in 465 people with environmental sensitivities. A second area of inquiry involved negative reactions to general anesthesia. Results showed that the most common barriers to receiving care were the inability to find a provider who understands environmental sensitivities and a lack of accessibility due to chemical and electromagnetic exposures in health care environments. Lower income and poorer health (longer illness, a worsening or fluctuating course of illness, and a higher level of disability) were significantly correlated with the total number of reported unmet health care needs. Some people with environmental sensitivities reported having negative reactions to anesthesia of long duration; most common were nausea and vomiting, fatigue, and reduced cognitive ability.

The correlation between mental health and multiple chemical sensitivity: a survey study in Japanese workers

OBJECTIVE

This study was designed to determine the correlation between mental health and multiple chemical sensitivity (MCS).

METHOD

The present study was conducted at two companies in 2011; both in Kyushu, Japan. The "subjective symptoms" subscale of the "Self-diagnosis Checklist for Assessment of Workers' Accumulated Fatigue" was used as a mental health subscale. To determine if multiple chemical exposure has an impact on mental health, we composed an original path model using structural equation analysis.

RESULT

Our final path model can be regarded as good: CMIN/DF = 1.832, CFI = 0.996, and RMSEA = 0.038, AIC = 71.158. As expected, chemical sensitivity and other chemical sensitivity scores predicted the health effects of multiple chemical exposure (β = 0.19, 0.64). Mental health was predicted by symptom severity and life impact (β = 0.56 and 0.12), which were both affected by multiple chemical exposure (β = 0.38 and 0.89, respectively).

CONCLUSION

As far as we are aware, this is the first study using path analysis to explore whether MCS can indicate mental health in worker populations worldwide, and we found a significant causal relationship between them. This could indicate that more focus should be placed on the impact of MCS on mental health in future investigations.

Does usage of a room air freshener affect the nasal mucosa?

BACKGROUND

Effects of chemicals emitted from the room air freshener sprays (RAFSs) on nasal mucosa are still unclear. The purpose of this study was to investigate effects of RAFSs on the nasal mucosa of rats for different time intervals.

METHODS

Twenty-eight rats were randomly divided into four experimental groups: group 1 (n = 7) was the control group and not exposed to RAFS or other chemicals, group 2 (n = 7) was exposed to RAFS for 1 month, group 3 (n = 7) was exposed to RAFS for 2 months, and group 4 (n = 7) was exposed to RAFS for 3 months. Samples from the nasal septum were stained using hematoxylin and eosin solution, examined by a pathologist using a light microscope, and analyzed with Fisher's exact test.

RESULTS

We observed that distinct histopathological differences in the nasal mucosa of exposed rats depends on different time intervals (p < 0.05). Increased congestion was found after the 1st month of exposure (group 2). Although edema and mild inflammatory cell infiltration, including some eosinophils, was seen after the 2nd month (group 3), squamous metaplasia, numerous eosinophils, and intense inflammatory cell infiltration began after 3 months of exposure (group 4).

CONCLUSION

Our results showed that continuous use of RAFS can cause inflammation and eosinophilic infiltration in rats, which begins after 2 months of exposure and may lead to metaplasia after 3 months. Because of differences in body size, geometry, and physiological responses of rats, the extrapolation of these results to humans is not straightforward. However, any such comparison should be made with caution. Finally, more performance is necessary to clarify this subject.

Prevalence and interannual changes in multiple chemical sensitivity in Japanese workers

OBJECTIVE

We aimed to evaluate the prevalence rates and interannual fluctuations in multiple chemical sensitivity (MCS) in Japanese workers.

METHODS

We assessed MCS using the Quick Environmental Exposure and Sensitivity Inventory, employing both Miller and Japanese criteria. Workers of two manufacturing companies located in Kyushu, Japan, were assessed, with company A surveyed in 2003, 2006 and 2011, and company B in 2003 and 2011.

RESULTS

In company A, the Miller criteria-based MCS prevalence rate was higher in 2011 than in 2003, and according to the Japanese criteria, it was higher in 2011 than 2006. In company B, the Miller criteria-based MCS prevalence rate was lower in 2011 than in 2003.

CONCLUSION

The results indicated that MCS exists among industrial workers in Japan. We found no statistically significant interannual changes in MCS rates.

Chemical intolerance among hairdressers in Denmark

Objectives

To investigate the prevalence and the severity of fragrance-related symptoms among hairdressers in Denmark compared with the Danish general population. Further, to characterize former hairdressers who are severely chemically intolerant to fragranced products in relation to sex, age and health- and work-related reasons for leaving the hairdressing profession.

Methods

The study population consisted of all hairdressers who graduated from the public vocational schools in Denmark during 1985 and 2007 (n = 7840) and a random sample of individuals from the Danish general population (n = 6000). Both populations received a postal questionnaire on symptoms from inhalation of fragranced products and the resultant behavioural consequences. All former hairdressers also answered additional questions on health- and work-related reasons for leaving the profession.

Results

No differences were found in the prevalence (OR = 1.0, CI = 0.89–1.14) or the severity (OR = 1.1, CI = 0.80–1.51) of symptoms from inhalation of fragranced products in hairdressers compared with the general population. Among hairdressers, however, experience of fragrance-related symptoms (OR = 1.2, CI = 1.01–1.31) and adjustments of social (OR = 1.8, CI = 1.12–2.80) and occupational conditions (OR = 2.8, CI = 1.84–4.25) were reported significantly more often by former hairdressers than current hairdressers.

Conclusions

The prevalence and the severity of fragrance-related symptoms were similar in hairdressers and the general population. Former hairdressers were more affected by fragranced products than current hairdressers were. Although fragrance-related symptoms did not seem to be more frequent among hairdressers, the hairdressing profession might pose a problem for those who are chemically intolerant.

Multiple chemical sensitivity and the workplace: current position and need for an occupational health surveillance protocol

Multiple chemical sensitivity, commonly known as environmental illness, is a chronic disease in which exposure to low levels of chemicals causes correlated symptoms of varying intensity. With the continuous introduction of new substances, people with MCS suffer significant limitations to their living environment and frequently to their workplace. This paper describes the current situation as regards MCS and the critical points in its case definition, which is still not generally agreed upon; this makes it difficult to recognize with certainty, especially, its precise relationship with work. Other problems arise in relation to the occupational physician's role in diagnosing and managing the worker with the disorder, the question of low levels of exposure to chemicals, and the best measures possible to prevent it. A diagnostic “route” is proposed, useful as a reference for the occupational physician who is often called in first to identify cases suspected of having this disease and to manage MCS workers. Work-related problems for people with MCS depend not only on occupational exposure but also on the incompatibility between their illness and their work. More occupational physicians need to be “sensitive” to MCS, so that these workers are recognized promptly, the work is adapted as necessary, and preventive measures are promoted in the workplace.

Chemical sensitivity: pathophysiology or pathopsychology?

BACKGROUND

Escalating numbers of people throughout the world are presenting to primary care physicians, allergists, and immunologists with myriad clinical symptoms after low-level exposure to assorted everyday chemicals such as smoke, perfumes, air fresheners, paints, glues, and other products. This clinical state is referred to by various diagnostic labels, including multiple chemical sensitivity disorder, environmental intolerance, chemical sensitivity (CS), and sensitivity-related illness, and has been the subject of much controversy within the health care community.

OBJECTIVE

The goal of this study was to provide a brief overview of the etiology, pathogenesis, clinical presentation, and management of CS. An evaluation of the medical community's response to this emerging diagnosis was also explored.

METHODS

This review was prepared by assessing available medical and scientific literature from MEDLINE, as well as by reviewing numerous books, toxicology journals, conference proceedings, government publications, and environmental health periodicals. A primary observation, however, is that there is limited scientific literature available on the issue of CS. The format of a traditional integrated review was chosen because such reviews play a pivotal role in scientific research and professional practice in medical issues with limited primary study and uncharted clinical territory.

RESULTS

The sensitization state of CS seems to be initiated by a significant toxic exposure, occurring as a 1-time event, or on surpassing a threshold of toxicity after toxicant accrual from repeated lower-level exposures. Once sensitized through a toxicant-induced loss of tolerance, individuals exposed to inciting triggers such as minute amounts of diverse everyday chemicals may experience various clinical and immune sequelae, sometimes involving lymphocyte, antibody, or cytokine responses. Precautionary avoidance of inciting triggers will prevent symptoms, and desensitization immunotherapy or immune suppression may improve symptoms in some cases. Sustained resolution of the CS state occurs after successful elimination of the accrued body burden of toxicants through natural mechanisms of toxicant bioelimination and/or interventions of clinical detoxification. Despite extensive clinical evidence to support the veracity of this clinical state, many members of the medical community are reluctant to accept this condition as a pathophysiologic disorder.

CONCLUSIONS

The emerging problem of ubiquitous adverse toxicant exposures in modern society has resulted in escalating numbers of individuals developing a CS disorder. As usual in medical history, iconoclastic ideas and emerging evidence regarding novel disease mechanisms, such as the pathogenesis of CS, have been met with controversy, resistance, and sluggish knowledge translation.

Chemical intolerance in primary care settings: prevalence, comorbidity, and outcomes

PURPOSE

This study extends previous community-based studies on the prevalence and clinical characteristics of chemical intolerance in a sample of primary care clinic patients. We evaluated comorbid medical and psychiatric disorders, functional status, and rates of health care use.

METHODS

A total of 400 patients were recruited from 2 family medicine clinic waiting rooms in San Antonio, Texas. Patients completed the validated Quick Environmental Exposure and Sensitivity Inventory (QEESI) to assess chemical intolerance; the Primary Care Evaluation of Mental Disorders (PRIME-MD) screen for possible psychiatric disorders; the Dartmouth-Northern New England Primary Care Cooperative Information Project (Dartmouth COOP) charts for functional status; and the Healthcare Utilization Questionnaire.

RESULTS

Overall, 20.3% of the sample met criteria for chemical intolerance. The chemically intolerant group reported significantly higher rates of comorbid allergies and more often met screening criteria for possible major depressive disorder, panic disorder, generalized anxiety disorder, and alcohol abuse disorder, as well as somatization disorder. The total number of possible mental disorders was correlated with chemical intolerance scores (P <.001). Controlling for demographics, patients with chemical intolerance were significantly more likely to have poorer functional status, with trends toward increased medical service use when compared with non-chemically intolerant patients. After controlling for comorbid psychiatric conditions, the groups differed significantly only regarding limitations of social activities.

CONCLUSIONS

Chemical intolerance occurs in 1 of 5 primary care patients yet is rarely diagnosed by busy practitioners. Psychiatric comorbidities contribute to functional limitations and increased health care use. Chemical intolerance offers an etiologic explanation. Symptoms may resolve or improve with the avoidance of salient chemical, dietary (including caffeine and alcohol), and drug triggers. Given greater medication intolerances in chemical intolerance, primary care clinicians could use the QEESI to identify patients for appropriate triage to comprehensive nonpharmacologic care.

Functional somatic syndromes, anxiety disorders and the upper airway: a matter of paradigms

The relationship between the functional somatic syndromes, anxiety disorders and the upper airway (particularly, sleep disordered breathing) remains ambiguous. This ambiguity, despite a growing body of research supporting a relationship, may result from the absence of a paradigm to explain how upper airway dysfunction can promote disorders commonly associated with one's mental health. This review models the functional somatic syndromes and anxiety disorders as consequences of chronically increased hypothalamic-pituitary-adrenal axis activity. It then examines the literature supporting a relationship between these disorders and upper airway dysfunction during wakefulness and sleep. Finally, building upon an existing paradigm of neural sensitization, sleep disordered breathing is linked to functional somatic syndromes and anxiety disorders through chronic activation of the hypothalamic-pituitary-adrenal axis.

Sensitivity-related illness: the escalating pandemic of allergy, food intolerance and chemical sensitivity

The prevalence of allergic-related diseases, food intolerance, and chemical sensitivities in both the pediatric and adult population has increased dramatically over the last two decades, with escalating rates of associated morbidity. Conditions of acquired allergy, food intolerance and chemical hypersensitivity are frequently the direct sequelae of a toxicant induced loss of tolerance (TILT) in response to a significant initiating toxic exposure. Following the primary toxicant insult, the individuals become sensitive to low levels of diverse and unrelated triggers in their environment such as commonly encountered chemical, inhalant or food antigens. Among sensitized individuals, exposure to assorted inciting stimuli may precipitate diverse clinical and/or immune sequelae as may be evidenced by clinical symptoms as well as varied lymphocyte, antibody, or cytokine responses in some cases. Recently recognized as a mechanism of disease development, TILT and resultant sensitivity-related illness (SRI) may involve various organ systems and evoke wide-ranging physical or neuropsychological manifestations. With escalating rates of toxicant exposure and bioaccumulation in the population-at-large, an increasing proportion of contemporary illness is the direct result of TILT and ensuing SRI. Avoidance of triggers will preclude symptoms, and desensitization immunotherapy or immune suppression may ameliorate symptomatology in some cases. Resolution of SRI generally occurs on a gradual basis following the elimination of bioaccumulated toxicity and avoidance of further initiating adverse environmental exposures. As has usually been the case throughout medical history whenever new evidence regarding disease mechanisms emerges, resistance to the translation of knowledge abounds.

Coping strategies, social support and responsibility in chemical intolerance

AIMS AND OBJECTIVES

To study coping strategies, social support and responsibility for improvement in chemical intolerance (CI).

BACKGROUND

Limited knowledge of CI among health professionals and lay persons places demands on the chemically intolerant individual's coping strategies and perception of social support and ability to take responsibility for improvement. However, there is sparse literature on these issues in CI.

DESIGN

A cross-sectional, questionnaire-based, quasi-experimental study.

METHOD

Fifty-nine persons with mild, 92 with moderate and 31 with severe CI participated by rating (i) usage and effectiveness of six problem- and six emotion-focused coping strategies, (ii) emotional, instrumental and informative support provided by various sources and (iii) society's and the inflicted individual's responsibility for improvement.

RESULTS

The participants reported that the most commonly used and effective coping strategies were avoiding odorous/pungent environments and asking persons to limit their use of odorous/pungent substances (problem-focused strategies) as well as accepting the situation and reprioritising (emotion-focused strategies). High intolerance severity was associated with problem-focused coping strategies and relatively low intolerance with emotion-focused strategies. More emotional than instrumental and informative support was perceived, predominantly from the partner and other family members. Responsibility attributed to society was also found to increase from mild to moderate/severe intolerance.

CONCLUSIONS

Certain coping strategies are more commonly used and perceived as more effective than others in CI. However, intolerance severity plays a role regarding both coping strategies and responsibility. Emotional support appears to be the most available type of support.

RELEVANCE TO CLINICAL PRACTICE

For improved care, certain coping strategies may be suggested by nurses, the healthcare system needs to provide better social support to these patients and the issue of responsibility for improvement may be discussed with the patient.

Factors associated with prospective development of environmental annoyance

OBJECTIVES

Idiopathic environmental intolerance (IEI) has in cross-sectional studies been associated with emotional problems and psychiatric disorders. However, in the absence of prospective studies it has not been possible to determine whether emotional problems precede the onset of IEI, or are a consequence of IEI. The purpose of this study was to address this issue in a prospective panel study design.

METHODS

The study sample (n=10 275) responded to a postal survey that included five questions regarding annoyance from environmental factors, at baseline and at follow-up five years later. Associations between a number of self-rating scales of stress, subjective health, and working conditions at baseline on one hand, and development of environmental annoyance from baseline to follow-up on the other, were examined.

RESULTS

Participants having developed environmental annoyance between baseline and follow-up had at baseline reported more subjective health complaints, higher levels of stress, strain, and lack of recovery, more dissatisfaction with their work situation, and lower personal social support, compared to participants not developing environmental annoyance.

CONCLUSION

Elevated subjective health complaints, high stress in daily life and a strained work situation, all possible signs of sustained arousal, increase the risk of developing annoyance to environmental factors. The results fit the hypothesis that reduced subjective health, over the course of time, may be attributed to environmental factors.

[Multiple chemical sensitivity: epidemiological, clinical and prognostic differences between occupational and non-occupational cases]

BACKGROUND AND OBJECTIVE

The progressive increase in cases of multiple chemical sensitivity (MCS) syndrome and the lack of studies which associate the syndrome with possible occupational origins means that further research in this field is required. The objective of this study was to compare the epidemiological, clinical and prognostic aspects of cases of MCS of occupational and non-occupational origin.

PATIENTS AND METHOD

Observational study of patients diagnosed with MCS by the toxicology outpatients clinic of the Hospital Clinic of Barcelona between 2002 and 2007. The occupational and non-occupational origin of MCS was considered as an independent variable. The dependant variables were occupational activity, triggering agents of MCS, chemical agents associated with the development of clinical manifestations, severity of the symptoms, comorbidities and work disability. Percentages were compared between groups.

RESULTS

A total of 165 patients were included: The mean age was 47.7 years and 90.9% were women. There were significant differences between patients of occupational and non-occupational origin with respect to comorbidities such as chronic fatigue syndrome (68.1% versus 88.5%; p=0.002) and fibromyalgia (49.3% versus 73.9%; p=0.002), temporary disability (60.9% versus 39.6%; p=0.006) and permanent disability (8.7% versus 22.9%; p=0.006).

CONCLUSIONS

Cases of MCS attributed to an occupational origin had fewer comorbidities and less permanent disability than those of non-occupational origin.

Sickness-related dysfunction in persons with self-reported multiple chemical sensitivity at four levels of severity

AIM

To examine quality of life outcome for persons who self-report chemical sensitivity, often referred to as multiple chemical sensitivity.

BACKGROUND

Multiple chemical sensitivity is poorly understood with few providers specialising in its treatment. This lack of treatment and the ubiquity of chemicals engender severe life impacts such as job loss, financial loss, social isolation and even homelessness for persons who experience these sensitivities.

DESIGN

Survey.

METHOD

We examined chemical incitants, symptoms and sickness-related behavioural dysfunction as measured by the Sickness Impact Profile in 254 persons self-identified with multiple chemical sensitivity.

RESULTS

Chemicals rated as causing the most symptomatology in respondents were pesticide, formaldehyde, fresh paint, new carpet, diesel exhaust, perfume and air fresheners. The five highest rated symptoms in this sample were tiredness/lethargy, difficulty concentrating, muscle aches, memory difficulties and long-term fatigue. Overall mean Sickness Impact Profile score was 25.25%, showing serious impairment, with the most serious dysfunction in the categories of work (55.36%), alertness behaviour (53.45%) and recreation and pastimes (45.20%).

CONCLUSION

Multiple chemical sensitivity is an important health care issue because it often includes serious dysfunction, is poorly understood by providers and poses extensive financial and treatment obstacles for those who experience it.

RELEVANCE TO CLINICAL PRACTICE

Persons with multiple chemical sensitivity seek medical treatment in a variety of contexts and informed providers can both avoid iatrogenic harm due to medical exposures and provide any possible treatment for the chemical sensitivities. Understanding the impact of the health condition is crucial to communicate with and treat persons who experience the sensitivities.

Modern health worries and idiopathic environmental intolerance

OBJECTIVE

We conducted two studies to test whether modern health worries (MHWs) were associated with central features of a condition called idiopathic environmental intolerance (IEI) and medical care utilization.

METHODS

In Study 1, 474 Internet users completed an Internet-based questionnaire that assessed MHWs, IEI features, and medical care utilization. In Study 2, the diagnostic specificity of MHWs was investigated by comparing the level of MHWs of three diagnostic groups: 46 people with IEI, 38 people with somatoform disorder but without IEI, and 46 people with neither IEI nor somatoform disorder.

RESULTS

The good psychometric properties of the MHW scale were confirmed. MHWs were related to various features of IEI, and people who met IEI case criteria showed consistently higher levels of MHWs compared with people without IEI. The link between MHWs and number of doctor visits was mediated by perceived IEI complaints. In Study 2, the MHW scale effectively discriminated the IEI group from the non-IEI groups.

CONCLUSIONS

These results suggest that MHWs may contribute to the development of IEI. However, only prospective longitudinal studies will enable us to determine the predictive importance of MHWs for later development of IEI.

Human awareness and uses of odor cues in everyday life: Results from a questionnaire study in children

The Children's Olfactory Behavior in Everyday Life questionnaire was developed to assess attention to, and uses of, odors in real-life situations, and to evaluate individual variations. The tool comprises 16 items prompting self-reports of active seeking, awareness and affective reactivity to odors of food, people and the environment. Children (102 girls, 113 boys) aged 6–10 years participated in the study. The results revealed that girls were significantly more olfaction-oriented than boys, especially towards the odors of people, self and the environment. An increasing ability of children to describe the odor facets of their perceptual world was found between 6 and 10 years, partly due to ameliorating verbal skills. Finally, owning an “attachment object” was linked to olfactory reactivity to odors, especially in social and affective contexts. Overall, this research contributes to expand our understanding of the behavioral importance of odors in children and its individual variations, and it brings additional arguments against the prevalent concept of functional microsmaty applied to the human species.

Psychosocial factors that aggravate the symptoms of sick house syndrome in Japan

Over the last 30 years in Japan, there has been a 10% increase in the number of people suffering from sick house syndrome due to toxic chemicals released from construction materials and wallpaper. This syndrome can develop into the more complex and disabling, chemical sensitivity syndrome, so preventing early exposure to toxins at home is critical in reducing the likelihood of health problems in the community. A qualitative study was undertaken using ethnographic methods to identify the psychosocial aggravating factors of sick house syndrome. As a result, the participants identified three aggravating factors that extended the period of exposure of the participant to toxic chemicals: a lack of knowledge about the disorder; the difficulty in establishing a diagnosis; and the difficulty of taking radical measures to improve the home environment. Public awareness of sick house syndrome and the dangers of toxicity from construction materials is vital to eliminate these aggravating factors and to prevent illness.

Psychological predictors of short- and medium term outcome in individuals with idiopathic environmental intolerance (IEI) and individuals with somatoform disorders

Idiopathic environmental intolerance (IEI), also known as multiple chemical sensitivity (MCS), is defined as a chronic polysymptomatic condition that cannot be explained by an organic disease. Previous studies suggest that IEI may be a variant of somatoform disorders (SFD), because both disorders overlap with respect to symptoms and psychological features of somatization. However, little is known about the short- and medium-term outcome of IEI and psychological outcome predictors. Two clinical groups (IEI and SFD) and a comparison group (CG) were followed through 32 mo to assess both the outcome, and the extent to which trait anxiety and somatic symptom attribution (assessed at first examination) predict outcome presented 12 and 32 mo later. Outcome measures were the number of self-reported IEI symptoms, IEI triggers, IEI-associated functional impairments, and the number of somatoform symptoms. In addition, the course of the 2 syndromes over the 32-mo follow-up period was investigated with standardized screening scales. The 3 diagnostic groups consisted of 46 subjects with IEI, 38 subjects with SFD but without IEI, and 46 subjects (CG) with neither IEI nor SFD. Syndrome stability was high over the 32-mo follow-up period, and at both follow-ups IEI and non-IEI subjects differed on all IEI outcome measures (symptoms, triggers, functional impairments). Both trait anxiety and somatic attribution (the tendency to attribute common somatic complaints to an illness) predicted outcome. In addition, somatic attribution was found to partially mediate the effect of trait anxiety on outcome in the IEI group. In conclusion, these results suggest that IEI is a chronic and disabling condition and that trait anxiety contributes to the maintenance of the disorder via somatic attributions.

Sensibilidad química múltiple: análisis de 52 casos

BACKGROUND AND OBJECTIVE

Multiple chemical sensitivity (MCS) is characterized by a loss of tolerance to various environmental chemicals. The objective of this study was to describe patients with MCS seen in our hospital.

PATIENTS AND METHOD

Patients consecutively seen by the Toxicology and Chronic Fatigue Units who presented symptoms of MCS were included. The diagnosis was clinical. All patients completed the Quick Environmental Exposure and Sensitivity Inventory (QEESI) questionnaire.

RESULTS

Fifty-two patients were included. The average age (standard deviation) was 47.2 (7.6) years, and 46 (88%) were females. The origin of the syndrome was related to occupational exposure to various chemical agents in 31 cases (59.6%), including occupational accidents in 14 patients (fumigation of the workplace with insecticides). In 20 patients (38.5%), the syndrome could not be associated with any toxic exposure and was considered a manifestation of chronic fatigue syndrome. The QEESI showed mean scores of 72.9 (18.6) on the chemical inhalant intolerance scale, 45.5 (20.6) on the other intolerances scale, 69.8 (20.6) on the symptom severity scale, 4.4 (1.8) on the masking index and 66.6 (21.7) on the life impact scale. All patients were followed up for a minimum of 12 months, and during this period they remained stable with no deaths.

CONCLUSIONS

MCS normally affects middle-aged women. It is frequently triggered by exposure to chemical agents, especially insecticides. An association with chronic fatigue syndrome is common. The prognosis is good but the patients' quality of life is seriously affected.

Chemical sensitivity and the work place environment: research needs

Large numbers of studies of multiple chemical sensitivity (MCS) have been performed, particularly in clinical settings. Epidemiological studies in the area are scarce, and this is also the case for cacosmia. Very few have studied the work place conditions for the MCS patient at the onset of symptoms, neither the chemical exposure nor psychosocial conditions. This type of research is of interest to understand the development of the syndrome and to suggest preventive actions in the work places.

Multiple chemical sensitivity syndrome (MCS)--suggestions for an extension of the U.S. MCS-case definition

PURPOSE

To validate and extend the US case definition for the Multiple Chemical Sensitivity Syndrome (MCS) from 1999 by a systematic literature-review.

DATA SOURCE

MEDLINE-research from 1997 to August 2003, research in the Cochrane-Library in August 2003, earlier reviews since 1997.

STUDY SELECTION

Headings and abstracts were screened by one reviewer. All references dealing with multiple chemical sensitivities (MCS) which covered topics of interest such as symptom-profiles, differential diagnostic procedures, etc. were included in the analysis.

DATA EXTRACTION AND SYNTHESIS

Topic-specific data extraction and synthesis was done by one reviewer. Data interpretation was discussed by all other authors.

RESULTS

Out of 1429 references 36 publications proved to be suitable for the review. The results can be summarized as follows: exposure-related symptoms associated with self-reported multiple chemical sensitivities can be divided into non-specific complaints of the central nervous system--CNS (main characteristics) and functional disturbances in other organ systems (optional complaints). There is a significant overlap of MCS, CFS and fibromyalgie. At present no standards for a diagnostic procedure based on the criteria outlined above are existing

CONCLUSIONS

MCS should only be diagnosed in patients who are mainly suffering from exposure-related non-specific complaints of the Central nervous system. The suggested diagnostic procedure follows the guidelines for CFS which are extended by diagnostic clarification of functional disturbances in other organ systems.

Disability-induced identity changes in persons with multiple chemical sensitivity

In this qualitative study, the authors asked respondents with multiple chemical sensitivity (MCS) in an open-ended question how having the condition affected their identities. Authors then examined responses for themes, which they discuss within the framework of critical theory. Emergent themes included loss of a stable, familiar personality, loss of self-positioning, emotional suppression to meet others' expectations, redesigning the planned life, forced growth, struggling with support, discovering the spiritual self, and identity reconsolidation. The authors compare findings with published works on adjustment to chronic illness and other delegitimized illnesses, find them to be fairly congruent, and then discuss problems regarding cultural acceptance of MCS as a condition caused by chemical exposure.

Multiple chemical sensitivities: stigma and social experiences

Multiple Chemical Sensitivity (MCS), an intolerance to everyday chemical and biological substances in amounts that do not bother other people, is a medically contested condition. In addition to symptoms and the ongoing difficulties of living with this condition, this hidden and stigmatized disability strongly impacts social relationships and daily life. Based on an ethnographic study, this article introduces the context of MCS in terms of cultural themes, the media, and the economic power of industries that manufacture the products that make people with MCS sick. Participants' experiences with family members and friends, in work and school settings, and with physicians exemplify the difficulties of living with MCS. I dedicate this article to Joan Ablon, my professor and mentor, whose work has always inspired my thinking and research topics.

Interdisciplinary diagnostics in environmental medicine--findings and follow-up in patients with chronic medically unexplained health complaints

PROBLEM

In patients attributing their chronic, medically unexplained complaints to environmental factors the greatest challenge is to overcome their disabling belief in toxicogenic explanations.

METHOD

Patients presenting with health complaints that they attributed to environmental causes in an environmental outpatient department (EOPD) within a university medical center in Germany were studied. An interdisciplinary review of previously diagnosed medical conditions, current clinical consultations, personal risk communication and therapeutic advice is presented. Additionally, patient contentedness, complaint development, and belief in environmental attribution in a follow-up interview are given.

RESULTS

The open, prospective study comprises 51 patients reporting more than one complaint. Symptoms had lasted for more than 3 years in 63% of the cases. Seventy percent attributed their complaints to more than one environmental cause. The clinical diagnostic procedure reduced the number of prediagnosed clinical conditions by 50%. Numerous foregoing environmental laboratory analyses had overestimated toxicologically relevant findings. These were not confirmed in 80% (8/10) of the cases. In 8% (n = 4) of the patients a relevant environmental or occupational medical condition was found. A mental or behavioral condition was not considered to have first priority in explaining all complaints in 43% (22/51) of the patients. Among these, mostly respiratory or skin-related diseases were found. All patients contacted participated in a follow-up study after a minimum of 21 months. Sixty-seven percent reported having felt that they were taken seriously, 38% felt better after the beginning of the study, and 45% were no longer certain about the importance of the environmental attribution. Since 83% of the patients with a preceding residential diagnosis of MCS or SBS still believed in environmental causes of their complaints in the follow-up study, we conclude that these prediagnoses appear to be a risk for persisting attribution of the environmental factor. About one third (37%) of these patients with complaints that had not been medically explained by an organic condition during interdisciplinary diagnostics had meanwhile consulted a psychotherapist.

CONCLUSIONS

Interdisciplinary diagnostics and scientifically based risk assessment in a specialized clinical center were effective and mostly well accepted by the patients and resulted in reduced attribution of complaints to environmental conditions. No indication was found that patients with complaints not medically explained by organic conditions were managed less successfully by this approach. Considering the high costs that these patients have previously caused, it appears valuable to apply an interdisciplinary diagnostic strategy.

Multiple chemical sensitivity and idiopathic environmental intolerance (part two)

Multiple chemical sensitivity/idiopathic environmental intolerance (MCS/IEI) is a commonly used diagnostic term for a group of symptoms without apparent organic basis. The symptoms are characteristic of dysfunction in multiple organ systems. They wax and wane fluctuate according to exposure to low levels of chemical agents in the patient's environment, and sometimes begin after a distinct environmental change or injury such an industrial accident or chemical introduced after remodeling. Although traditional medical organizations have not agreed on a definition for this syndrome, it is being increasingly recognized and makes up an increasing percentage of the caseload at occupational/environmental medical clinics.Part two of this review article discusses diagnosis, clinical examination, long-term follow up of MCS/IEI, and the role of physicians, research on odor and treatment, diseases with similar symptoms, and further research regarding MCS/IEI patients.

Multiple chemical sensitivity and idiopathic environmental intolerance (part one)

Multiple chemical sensitivity/idiopathic environmental intolerance (MCS/IEI) is a commonly used diagnostic term for a group of symptoms. These symptoms have been described and commented on for more than 15 years in the USA. Recently, it has also been observed in Japan. The main features of this syndrome are multiple symptoms involving in multiple organ systems that are precipitated by a variety of chemical substances with relapses and exacerbation under certain conditions when exposed to very low levels which do not affect the population at large. There are no laboratory markers or specific investigative findings. Although traditional medical organizations have not agreed on a definition for this syndrome due to the lack of obvious evidence to demonstrate the existence of these symptoms, it is being increasingly recognized. It constitutes an increasing percentage of the caseload at occupational/environmental medical clinics.Part one of this review article discusses pathophysiological theories, substances which cause symptoms, prevalence in the general and specific populations, past history and family history, and clinical symptoms of MCS/IEI patients.

Symptomatology and etiology of multiple chemical sensitivities in the southeastern United States

A questionnaire was administered to individuals who had reported a hypersensitivity to common chemical products in an earlier epidemiological study in the Atlanta, Georgia, metropolitan area. The questionnaire investigated the nature of the symptoms and factors that potentially initiated hypersensitivity and subsequently triggered reactions. Also examined were associated lifestyle modifications and the relationships of hypersensitivity with other illnesses. The authors found that a majority of hypersensitive individuals (52.2%) experienced either "severe" or "somewhat severe" symptoms. The most common triggers of symptoms were cleaning products (88.4%), tobacco smoke (82.6%), perfume (81.2%), pesticides (81.2%), and car exhaust (72.5%). Only 1.4% of the subjects had a prior history of emotional problems, whereas 37.7% developed such problems after the emergence of their hypersensitivity. Lifestyle modifications varied; 76.8% changed their household cleaning/personal hygiene products, 47.8% began using water and/or air filtration systems, and 13% found it necessary to change residence. Although hypersensitivity was more common in females than males, the condition affects individuals in all categories of race/ethnicity, age, household income, and educational level.

Is multiple chemical sensitivity a clinically defined entity?

In 1996 a WHO/IPCS Workshop has suggested to use as an appropriate descriptor of MCS the broader term "Idiopathic Environmental Intolerances (IEI)", in order to incorporate "a number of disorders sharing similar symptomatologies". Research was strongly encouraged. The following points have been put forward as a precondition to define MCS as a clinical entity: (a) establishment of diagnostic criteria, (b) identification of pathogenic mechanisms, together with, (c) an explanation of relationship between exposures and symptoms. Against this background, progress made in the fields of sensory physiology and neurobehaviour research must be debated. In particular, recent results on processing of cognitive stimuli have to be considered. IEI/MCS patients exhibited differences vs. controls in their reactions to intranasal challenge, consistent with changes in cognitive processing of suprathreshold chemosensory information. Trait anxiety and focus of attention have clearly been identified as major components in eliciting neurobehavioural MCS symptoms. Hence, the question as to whether MCS should be regarded as a clinically defined entity remains controversial, but important progress can be noticed in elucidating and defining the nature of this phenomenon, by a combined effort of several disciplines (toxicology and behavioural toxicology, psychology and psychophysiology, and clinical medicine). The new situation will call for a re-evaluation of traditional positions.

The Iowa follow-up of chemically sensitive persons

Clinical symptoms and self-reported health status in persons reporting multiple chemical sensitivities (MCS) are presented from a 9-year follow-up study. Eighteen (69%) subjects from a sample of 26 persons originally interviewed in 1988 were followed up in 1997 and given structured interviews and self-report questionnaires. In terms of psychiatric diagnosis, 15 (83%) met DSM-IV criteria for a lifetime mood disorder, 10 (56%) for a lifetime anxiety disorder, and 10 (56%) for a lifetime somatoform disorder. Seven (39%) of subjects met criteria for a personality disorder using the Personality Diagnostic Questionnaire-IV. Self-report data from the Illness Behavior Questionnaire and Symptom Checklist-90-Revised show little change from 1988. The 10 most frequent complaints attributed to MCS were headache, memory loss, forgetfulness, sore throat, joint aches, trouble thinking, shortness of breath, back pain, muscle aches, and nausea. Global assessment showed that 2 (11%) had "remitted", 8 (45%) were "much" or "very much" improved, 6 (33%) were "improved", and 2 (11%) were "unchanged/worse". Mean scores on the SF-36 health survey showed that, compared to U.S. population means, subjects reported worse physical functioning, more bodily pain, worse general health, worse social functioning, and more emotional-role impairment; self-reported mental health was better than the U.S. population mean. All subjects maintained a belief that they had MCS; 16 (89%) acknowledged that the diagnosis was controversial. It is concluded that the subjects remain strongly committed to their diagnosis of MCS. Most have improved since their original interview, but many remain symptomatic and continue to report ongoing lifestyle changes.

The compelling anomaly of chemical intolerance

In science, anomalies expose the limitations of existing paradigms and drive the search for new ones. In the late 1800s, physicians observed that certain illnesses spread from sick, feverish individuals to those contacting them, paving the way for the germ theory of disease. The germ theory served as a crude, but elegant formulation that explained dozens of seemingly unrelated illnesses affecting literally every organ system. Today, we are witnessing another medical anomaly-a unique pattern of illness involving chemically exposed groups in more than a dozen countries, who subsequently report multisystem symptoms and new-onset chemical, food, and drug intolerances. These intolerances may be the hallmark for a new disease process or paradigm, just as fever is a hallmark for infection. The fact that diverse demographic groups, sharing little in common except some initial chemical exposure event, develop these intolerances is a compelling anomaly pointing to a possible new theory of disease, one that has been referred to as "Toxicant-Induced Loss of Tolerance" ("TILT"). TILT has the potential to explain certain cases of asthma, migraine headaches, and depression, as well as chronic fatigue, fibromyalgia, and "Gulf War syndrome". It appears to evolve in two stages: (1) initiation, characterized by a profound breakdown in prior, natural tolerance resulting from either acute or chronic exposure to chemicals (pesticides, solvents, indoor air contaminants, etc.), followed by (2) triggering of symptoms by small quantities of previously tolerated chemicals (traffic exhaust, fragrances, gasoline), foods, drugs, and food/drug combinations (alcohol, caffeine). While the underlying dynamic remains an enigma, observations indicating that affected individuals respond to structurally unrelated drugs and experience cravings and withdrawal-like symptoms, paralleling drug addiction, suggest that multiple neurotransmitter pathways may be involved.

Anxiety and depressive states in multiple chemical sensitivity

Cases with multiple chemical sensitivity (MCS) frequently present mental symptoms. This study discusses the characteristics of the anxiety and depressive state of MCS by comparing patients of MCS with a gender and age-matched control group. In this investigation, MCS cases were selected among those satisfying the diagnostic criteria of Cullen after ruling out other physical diseases. Patients visiting ophthalmologists with other diseases were designated as the control. Evaluation of the anxiety and depressive state was performed in 48 cases of MCS and 48 controls using the Japanese version of the State-Trait Anxiety Inventory, the Self-rating Depression Scale (SDS), and the Hamilton Rating Scale for Depression. Significantly higher mean values of subjective anxiety and a depressive state were obtained in 18 MCS cases than in 18 controls for the follow-up patients, while no significant difference was observed between MCS and controls of 30 new patients for each group. Therefore, anxiety in MCS is characterized by the continuous high anxiety level. MCS is also characterized by a continuance of depressive state at a "neurotic level" category by SDS. The anxiety scores and depressive levels were highly correlated in MCS and controls at the first and subsequent appearances, except those in the follow-up control cases. In conclusion, both anxiety and a depressive state in MCS remained at high level until the subsequent examination, when those in controls decreased to a normal level.

A nine-year follow-up of people diagnosed with multiple chemical sensitivities

The authors assessed self-reported health status and clinical symptoms in people reporting multiple chemical sensitivities (MCS) at a 9-year follow-up interview using structured and semistructured instruments and self-report questionnaires. Of the original sample, 18 people (69%) consented to an interview. By use of the best estimate diagnostic method, 15 subjects (83%) met DSM-IV criteria for a lifetime mood disorder, 10 (56%) for a lifetime anxiety disorder, and 10 (56%) for a lifetime somatoform disorder. None of the subjects met the criteria for a substance use disorder (current or lifetime). The Illness Behavior Questionnaire and the Symptom Check-list-90-Revised results showed little change from 1988 and remained significantly different from the control group on many subscales. The authors conclude that the subjects remain strongly committed to the diagnosis of MCS, and although improved since their original interview, many remain symptomatic and continue to report ongoing lifestyle changes.

Quality of life and health-services utilization in a population-based sample of military personnel reporting multiple chemical sensitivities

We sought to assess quality of life and health-services utilization variables in persons with symptoms suggestive of multiple chemical sensitivity/idiopathic environmental intolerance (MCS/IEI) among military personnel. We conducted a cross-sectional telephone survey of a population-based sample of Persian Gulf War (PGW) veterans from Iowa and a comparison group of PGW-era military personnel. A complex sample survey design was used, selecting subjects from four domains: PGW active duly, PGW National Guard/Reserve, non-PGW active duty, and non-PGW National Guard/Reserve. Each domain was substratified by age, gender, race, rank, and military branch. The criteria for MCS/IEI were developed by expert consensus and from the medical literature. In the total sample, 169 subjects (4.6%) of the 3695 who participated (76% of those eligible) met our criteria for MCS/IEI. Persons who met the criteria for MCS/IEI more often reported the following than did other subjects: more than 12 days in bed due to disability, Veteran's Affairs disability status, Veteran's Affairs disability compensation, medical disability, and unemployment. MCS/IEI cases also had higher outpatient rates of physician visits, emergency department visits, and inpatient hospital stays. Subjects who met the criteria for MCS/IEI more often reported impaired functioning on each Medical Outcomes Study 36-Item Short Form subscale, compared with those who did not meet the criteria. We concluded that although the diagnosis of MCS/IEI remains controversial, the persons who met our criteria for the disorder are functionally impaired.

Olfaction and symptoms in the multiple chemical sensitivities syndrome

Whereas most idiosyncratic environmental sensitivity complaints do not fit known diagnoses, the multiple chemical sensitivities syndrome (MCS) is an extreme presentation that has defined diagnostic criteria. MCS symptomatics claim that they acquired a sensitized state as the result of a chemical exposure, usually to a solvent or pesticide, but not to a fragrance. Before this exposure, they did not experience symptoms. Following sensitization, symptoms increasing in number and severity with time are attributed by the MCS symptomatic to various exposures that are innocuous to most individuals. Although phenomenological studies have provided no evidence that particular odors elicit MCS symptoms, low levels of fragrances and perfumes are frequently associated with the reporting of MCS symptoms. This evaluation examines proposed mechanisms by which odorants and fragrances might cause either sensitization or elicitation of MCS symptoms, including altered odor sensitivity, primary irritancy or irritancy-induced upper airway reactivity, neurogenic switching of trigeminal irritancy signals, time-dependent sensitization and limbic kindling, CNS toxicity, and various psychiatric conditions. In no case was there persuasive evidence that any olfactory mechanism involving fragrance underlies either induction of a sensitized state or the triggering of MCS symptoms. Fragrances and other odorants could, however, be associated with symptoms as claimed by MCS symptomatics, because they are recognizable stimuli, but fragrance has not been demonstrated to be causal in the usual sense.

Hope in multiple chemical sensitivity: social support and attitude towards healthcare delivery as predictors of hope

This paper examines hope, as measured by the Herth Hope Scale, and its predictors in a sample of 305 people self-identified with multiple chemical sensitivity. The sample had relatively low levels of hope with scores unrelated to gender, severity or length of illness, income loss as a result of illness, or reported iatrogenic harm. Hope scores were positively correlated with perceived social support, having found personal growth through illness, age, reported level of supportiveness from a partner, an improved course of illness and level of reported safety of the home environment in regard to chemical exposures. Negative correlations were found with attitude toward healthcare delivery, fatigue and reported abuse/ostracism from family members other than partner. Social support, Healthcare Orientation, growth through illness, fatigue and age predicted hope scores accounted for 55% of the variance. Implications and suggestions for future research are discussed.

A rat model of neurobehavioral sensitization to toluene

Some individuals report that, following either a single high-level or repeated lower-level exposures to chemicals (initiation), subsequent exposure to very low concentrations of chemicals (triggering) produces a variety of adverse effects, including disruption of cognitive processes. Our objective was to model this two-step process in a laboratory animal. Two groups of 16 rats, eight male and eight female, received whole-body inhalation exposure to toluene, either at 80 ppm for 6 h/day for 4 weeks (Repeat group) or to 1600 ppm for 6 h/day on one day only (Acute group). Two other groups (Trigger group and Clean group) of 16 were sham-exposed. After 17 days without toluene exposure, the Acute, Repeat and Trigger groups began a series of daily toluene 'trigger' exposures (10 ppm for 1 h) followed immediately by testing on an operant repeated-acquisitions task requiring learning within and across sessions. The Clean group was sham-exposed prior to operant testing. Trigger or sham exposures and operant testing continued 5 days/week for 17 sessions. Analysis of variance revealed a variety of statistically significant (P < 0.05) differences between treatment groups. Furthermore, the patterns of differences between groups differed (P < 0.05) for female and male rats. For example, male rats of the Trigger group made the most responses, and female rats of the Repeat group responded most slowly. The observation of important changes in the operant behavior of female and male rats previously exposed to toluene, at relatively low concentrations (80 or 1600 ppm) and then later re-exposed at very low concentrations (10 ppm), is consistent with the experiences of humans reporting cognitive difficulties following acute or chronic exposures to chemicals.

Are we on the threshold of a new theory of disease? Toxicant-induced loss of tolerance and its relationship to addiction and abdiction

'Toxicant-induced loss of tolerance' (or TILT) describes a two-step disease process in which (1) certain chemical exposures, e.g., indoor air contaminants, chemical spills, or pesticide applications, cause certain susceptible persons to lose their prior natural tolerance for common chemicals, foods, and drugs (initiation); (2) subsequently, previously tolerated exposures trigger symptoms. Responses may manifest as addictive or abdictive (avoidant) behaviors. In some affected individuals, overlapping responses to common chemical, food, and drug exposures, as well as habituation to recurrent exposures, may hide (mask) responses to particular triggers. Accumulating evidence suggests that this disease process might underlie a broad array of medical illnesses including chronic fatigue, fibromyalgia, migraine headaches, depression, asthma, the unexplained illnesses of Gulf War veterans, multiple chemical sensitivity, and attention deficit disorder.

A controlled comparison of symptoms and chemical intolerances reported by Gulf War veterans, implant recipients and persons with multiple chemical sensitivity

Using the Environmental Exposure and Sensitivity Inventory (EESI), a standardized instrument for measuring chemical sensitivity, we obtained and compared ratings of symptoms, chemical (inhalant) intolerances, other intolerances (e.g., drugs, caffeine, alcohol, skin contactants), lifeimpact, and masking (ongoing exposures) in five populations: multiple chemical sensitivity (MCS) patients who did (n = 96) or did not (n = 90) attribute onset of their illness to a specific exposure event, patients with implanted devices (n = 87), Gulf War veterans (n = 72), and controls (n = 76). For each patient group, mean scores on the first four scales were significantly greater than for controls. MCS patients reported avoiding more chemical exposures (were less masked) than the other groups. Across groups, for a given level of symptoms, as masking increased, mean scores on the Chemical Intolerance Scale decreased. In contrast, mean scores on the Other Intolerance Scale appeared to be less affected by masking. These findings suggest that some patients with antecedent chemical exposures, whether exogenous (chemical spill, pesticide application, indoor air contaminants) or endogenous (implant), develop new chemical, food, and drug intolerances. Reports of new caffeine, alcohol, medication, food, or other intolerances by patients may signal exposure-related illness. Masking may reduce individuals' awareness of chemical intolerances, and, to a lesser degree, other intolerances.