The Chemical Odor Sensitivity Scale: reliability and validity of a screening instrument for idiopathic environmental intolerance

Malodors as environmental injustice: health symptoms in the aftermath of a hydrogen sulfide emergency in Carson, California, USA

In October 2021, hydrogen sulfide (H2S), a toxic odorous gas, was measured in Carson, California at concentrations reaching 7000 parts per billion (ppb), exceeding California’s 30 ppb acute air quality standard. Thousands of residents complained of malodors and headaches. We responded to community concerns by launching a rapid survey assessing symptoms. We recruited participants through door-to-door outreach, community events, and social media. During the emergency’s first week, 75% of the 108 total respondents experienced headaches, 72% experienced dizziness, and 63% experienced difficulty sleeping. About 60% of respondents (n=63, no response=7) noted the odor worsening their mental health. When adjusting for age, sex, and smoking, participants <2 km from the highest H2S concentrations reported higher prevalence of agitation (PD=0.23, 95% CI: 0.03, 0.42) and headaches (PR=0.14, 95% CI: −0.04, 1.31) compared to participants farther away. Malodors are underprioritized in environmental justice communities, despite H2S’s effects on mental and physical health.

Influence of face masks on the subjective impairment at different physical workloads

To quantify the subjective and cognitive impairment caused by wearing face masks at work, 20 men and 20 women (median age 47 years, range 19-65) were tested under different ergometer workloads while wearing surgical mask, community mask, FFP2 respirator or no mask in a randomized and partially double-blinded design. Masks were worn also at the workplace for four hours. Subjective impairment was recorded by questionnaires. Cognitive performance was tested before and after the workplace examination. Subjective feeling of heat, humidity, and difficult breathing increased with rising physical exertion and wearing time for all three mask types, most notably for FFP2. Even when blinded, participants with FFP2 reported difficult breathing already at rest. During physical exertion, individuals with low tolerance to discomfort reported significantly stronger impairment (OR 1.14, 95% CI 1.02-1.27). Regarding light work, older subjects (OR 0.95, 95% CI 0.92-0.98) and women (OR 0.84, 95% CI 0.72-0.99) showed significantly lower and atopic subjects stronger impairment (OR 1.16, 95% CI 1.06-1.27). No significant influence of mask wearing was detected on cognitive performance. Wearing a mask had no effect on cognitive performance, but led to discomfort which increased with physical exertion and wearing time. Individuals who tolerate discomfort poorly felt more impaired by wearing a mask during physical exertion.

Development and Psychometric Validation of the Taste And Smell Tool for Evaluation (TASTE) Questionnaire

Importance

The human senses of taste and smell are essential in everyday life. However, as clinical testing of the senses and patient-reported sensory problems are often diverging, additional validated questionnaires are essential for the evaluation of chemosensory impairments.

Objective

To develop an instrument with all relevant domains concerning chemosensory dysfunction and quality of life using modern psychometrics.

Design, Setting, and Participants

The study was designed as a questionnaire study for developing a new instrument. The study started in 2019 and was completed in 2022. Patients with chemosensory dysfunction were recruited from a specialized smell and taste clinic at an ear, nose, and throat department in Denmark. Healthy participants with no history of chemosensory dysfunction were recruited through social media.

Main Outcomes and Measures

Eight domains were included (distorted chemosensation, emotional, food and meals, social, hygiene, danger, work, and relationship), and 35 items were generated based on review of the existing literature and interviews with patients and experts. Participants were tested with the Major Depression Inventory, 36-Item Short Form Health Survey, Taste Sprays, and Sniffin' Sticks for chemosensory function. Descriptive statistics were calculated for all items. Reliability, internal consistency, and validity were investigated, and a Rasch model was fitted. Healthy controls (n = 39) filled out the questionnaire for comparison of known-groups validity. Confirmatory factor analysis was performed. Finally, item reduction was performed, resulting in a final version with 21 items in 8 domains.

Results

The study included responses from 316 patients, 183 women (58%) and 133 men (42%), with a mean (SD) age of 57 (15.1) years. Rasch model fit was acceptable with P > .05 for all items. An 8-dimensional confirmatory factor analysis model showed a better fit than a bifactor confirmatory factor analysis model. Cronbach α ranged from 0.65 to 0.86. Criterion validity with the Sniffin' Sticks, Taste Sprays, Major Depression Inventory, and the 36-Item Short Form Health Survey was satisfactory. The test-retest reliability was good in all domains, ranging from 0.55 to 0.86. All domains were discriminative, except the social and work domains.

Conclusions and Relevance

In this survey study, the instrument was validated with 8 domains related to chemosensory dysfunction and quality of life. All items had good internal consistency, test-retest reliability, interitem correlations, item-total correlations, and Rasch model fit. The questionnaire appears suitable for use in clinical and research settings.

Symptoms of Idiopathic Environmental Intolerance associated with chemicals (IEI-C) are positively associated with perceptual anomalies

OBJECTIVE

Idiopathic Environmental Intolerance (IEI; i.e. the experience of somatic symptoms attributed to environmental agents) represents a functional somatic syndrome of unclear aetiology. Based on previous findings that suggest an association between IEI and perceptual anomalies, this study aimed to investigate the relationship between symptoms of IEI associated with chemicals (IEI-C) and facets of the schizotypy spectrum.

METHODS

A cross-sectional study design was used with N = 410 (78.3% female) persons responding to an online survey in which chemical odor sensitivity (COS) and modern health worries (MHW) that are associated with IEI-C, as well as schizotypal personality traits (SPQ), hallucination proneness (LSHS) and delusional ideation (PDI) as core components of the schizotypy spectrum were assessed.

RESULTS

Schizotypal traits were found to be significantly positively associated with MHWs (r = 0.20, p = .01), COS (r = 0.23, p = .01), and showed significant positive associations with hallucination proneness. Magical thinking was found to exhibit a significant positive relationship with both MHW (r = 0.17, p = .01) and COS (r = 0.21, p = .01). These small associations between IEI-C and facets of the psychosis spectrum remained significant even after statistically controlling for individual levels of trait anxiety and depression.

CONCLUSION

Schizotypal personality traits, particularly magical thinking, and hallucination proneness, appear positively related to facets of IEI-C. The findings are of relevance for the advancement of theoretical models of IEI.

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.

Multiple Chemical Sensitivity in Patients Exposed to Moisture Damage at Work and in General Working-Age Population-The SAMDAW Study

A considerable proportion of patients having respiratory tract or voice symptoms associated with workplace moisture damage (MD) could have multiple chemical sensitivity (MCS). MCS is characterized by symptoms of different organ systems in association with low-level chemical exposure. The objective of this study was to assess the prevalence of MCS among patients referred to secondary health care because of respiratory or voice symptoms associated with workplace MD compared to the general working-age population. Using three subscales of the QEESI© questionnaire, we assessed MCS in the study patients and 1500 controls in the same district randomly selected from the Finnish Population Information System. Study patients had significantly more often high scores in chemical intolerance (39% vs. 23%, p = 0.001), symptom severity (60% vs. 27%, p < 0.001), and life impact subscales (53% vs. 20%, p < 0.001). Asthma, chronic rhinosinusitis, laryngeal problems, and atopy were not associated with the presence of MCS. MCS is common among patients referred to secondary health care with respiratory tract and/or voice symptoms associated with workplace MD, and it considerably affects their everyday life. MCS should be considered as a possible explanatory factor for MD-associated symptoms.

Advancing Environmental Health Literacy: Validated Scales of General Environmental Health and Environmental Media-Specific Knowledge, Attitudes and Behaviors

Environmental health literacy (EHL) involves understanding and using environmental information to make decisions about health. This study developed a validated survey instrument with four scales for assessing media-specific (i.e., air, food, water) and general EHL. The four scales were created as follows: 1) item generation: environmental health scientists and statisticians developed an initial set of items in three domains: knowledge, attitudes, and behaviors; 2) item review: items were reviewed for face validity; 3) validation: 174 public health students, the exploratory sample, and 98 community members, the test sample, validated the scales. The scales’ factor structure was based on exploratory factor analysis (EFA) and model fit was assessed through confirmatory factor analysis (CFA). For each scale, the final EFA resulted in an independent three-factor solution for knowledge, attitudes, and behaviors. Good fit for the three-factor structure was observed. Model fit for CFA was generally confirmed with fit indices. The scales showed internal consistency with Cronbach’s alpha from 0.63 to 0.70. The 42-item instrument represents an important contribution towards assessing EHL and is designed to enable meaningful engagement between researchers and community members about environmental health. The intended outcome is sustained community–academic partnerships benefiting research design, implementation, translation, dissemination, and community action.

Odor sensitivity impairment: a behavioral marker of psychological distress?

OBJECTIVE

Enhanced odor sensitivity, particularly toward threat-related cues, may be adaptive during periods of danger. Research also suggests that chronic psychological distress may lead to functional changes in the olfactory system that cause heightened sensitivity to odors. Yet, the association between self-reported odor sensitivity, objective odor detection, and affective psychopathology is currently unclear, and research suggests that persons with affective problems may only be sensitive to specific, threat-related odors.

METHODS

The current study compared adults with self-reported odor sensitivity that was described as functionally impairing (OSI; n = 32) to those who reported odor sensitivity that was non-impairing (OS; n = 17) on affective variables as well as quantitative odor detection.

RESULTS

Increased anxiety sensitivity, trait anxiety, depression, and life stress, even while controlling for comorbid anxiety and depressive disorders, was found for OSI compared to OS. While OSI, compared to OS, demonstrated only a trend increase in objective odor detection of a smoke-like, but not rose-like, odor, further analysis revealed that increased detection of that smoke-like odor was positively correlated with anxiety sensitivity.

CONCLUSION

These findings suggest that persons with various forms of psychological distress may find themselves significantly impaired by an intolerance of odors, but that self-reported odor sensitivity does not necessarily relate to enhanced odor detection ability. However, increased sensitivity to a smoke-like odor appears to be associated with sensitivity to aversive anxiogenic stimuli. Implications for the pathophysiology of fear- and anxiety-related disorders are discussed.

Exploratory Investigation of a Brief Cognitive Behavioral Intervention and Transcranial Direct Current Stimulation on Odor Sensitivity

OBJECTIVE

Enhanced odor sensitivity is a phenomenon that potentially underlies conditions such as multiple chemical sensitivity (MCS). Currently, there are no treatments that have been shown to effectively decrease odor sensitivity. Given similarities of odor hypersensitivity/MCS to pain sensitization disorders such as fibromyalgia, there may be a potential for interventions that improve pain tolerance to modulate odor sensitivity.

METHODS

This exploratory study randomized 72 healthy community adult volunteers to receive one of six treatments in between two assessments of thermal pain tolerance and odor threshold. Participants were randomized to receive either cathodal, anodal, or sham transcranial direct current stimulation (tDCS) aimed at dorsolateral prefrontal cortex. In addition, participants were provided a brief cognitive behavioral intervention (CBI) for pain consisting of task framing, cognitive restructuring, and distraction technique training, or a control intervention consisting of information about pain.

RESULTS

Persons who received a brief CBI showed significantly increased odor thresholds (reduced sensitivity) during intervention (F (1,62) = 7.29, p = .009, ηp = .11), whereas the control intervention was not associated with altered odor thresholds. Moreover, in those who received brief CBI, more severe anxiety associated with larger reductions in odor sensitivity (ρ = .364, p = .035). There was no effect of tDCS (F (2,62) = .11, p = .90) nor interaction between tDCS and CBI (F (2,62) = .32, p = .73).

CONCLUSIONS

Given the connection between anxiety and MCS, results suggest that CBT techniques for somatic processes may show promise in treating conditions characterized by increased sensitivity to odors (e.g., MCS).

Interindividual differences in chemosensory perception: Toward a better understanding of perceptual ratings during chemical exposures

Perceptions that arise from stimulation of olfactory and trigeminal receptors in the nasal cavity guide the evaluation of chemical environment in humans. Strong interindividual differences in these assessments may be attributed to nonsensory factors such as gender, anxiety, and chemical sensitivity. Knowledge regarding the influence of these factors originates mainly from basic odor research using short-term exposure scenarios. In situations with continuous chemical exposures-common in the working environment-their impact is less clear. To investigate their role during the exposure to workplace chemicals, 4-hour experimental exposure studies (total N = 105) using nine different airborne chemicals were summarized. In each study, subjects evaluated a single chemical in a controlled environment by rating five chemosensory perceptions, including odor intensity, disgust, annoyance, pungency, and burning, several times during occupational limit and low exposures. It was investigated whether the effects of trait-like modulators, such as anxiety and self-reported chemical sensitivity, depend on exposure-related factors and gender. Trait-like modulators markedly affected ratings by women, but not men. Highly anxious women reported more intense annoyance and disgust than less anxious women. Stronger self-reported chemical sensitivity was associated with increased ratings of pungency and burning in women exposed to occupational limit concentrations. This study demonstrates that a complex interplay of exposure-related factors, gender, and trait-like individual differences affects perceptual ratings during continuous chemical exposure. It seems necessary to incorporate the assessment of specific as well as general trait-like modulators into future experimental exposure studies.

Visually induced motion sickness can be alleviated by pleasant odors

Visually induced motion sickness (VIMS) is a common side effect in virtual environments and simulators. Several countermeasures against VIMS exist, but a reliable method to prevent or ease VIMS is unfortunately still missing. In the present study, we tested whether olfactory cues can alleviate VIMS. Sixty-two participants were exposed to a 15-min-long video showing a first-person-view bicycle ride that had successfully induced VIMS in previous studies. Participants were randomly assigned to one of three groups; the first group was exposed to a pleasant odor (rose) while watching the video, the second group was exposed to an unpleasant odor (leather), and the third group was not exposed to any odor. VIMS was measured using a verbal rating scale (0-20) and the Simulator Sickness Questionnaire. Results showed that only half of the participants who were exposed to the odor did notice it (n = 21), whereas the other half failed to detect the odor. However, among those participants who did notice the odor, the rose scent significantly reduced the severity of VIMS compared to the group that did not notice the odor. A moderate positive correlation between odor sensitivity and VIMS showed that participants with higher odor sensitivity also reported stronger VIMS. Our results demonstrate that olfaction can modulate VIMS and that a pleasant odor can potentially reduce VIMS. The relationship between olfactory perception, olfactory sensibility, and VIMS is discussed.

Prevalence and Characteristics of Chemical Intolerance: A Japanese Population-Based Study

Population-based cross-sectional study was performed to estimate the prevalence of chemical intolerance and to examine the characteristics of the sample. A Web-based survey was conducted that included 7,245 adults in Japan. The criteria for chemical intolerance proposed by Skovbjerg yielded a prevalence of 7.5% that was approximately consistent with that reported from a Danish population-based survey. Female gender, older age, and renovation in the house during the past 7 years were positively associated with chemical intolerance. Improvements in the condition were observed with daily ventilation habits. Medical history of atopic dermatitis, allergic rhinitis, food allergy, multiple chemical sensitivity, and depression were associated with chemical intolerance. Fatigue, depressed mood, and somatic symptoms were also positively correlated with chemical intolerance. Better elucidation of the causes, comorbidities, concomitants, and consequences of chemical intolerance has the potential to provide effective solutions for its prevention and treatment.

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.

[Multiple chemical sensitivity: a diagnosis not to be missed]

Multiple chemical sensitivity (MCS) is a chronic condition, which belongs to the group of medically unexplained syndromes. Patients (men as well as women) complain of many subjective symptoms such as nose and mouth irritation, sore throat, dyspnea, tiredness, dizziness, headache and concentration difficulties. Patient typically report at least four or five symptoms occurring when they are exposed to particular substances, at a very low concentration that usually does not cause symptoms or harm in normal individuals. The common feature of products that appear to be responsible (either occupational or domestic) is that they have a strong smell and include: solvent, paint, glue, tar, oil, pesticides, perfume, cosmetics and spray products. MCS is nowadays considered to be one aspect of idiopathic environmental intolerance (IEI) whose other main aspect is hypersensitivity to electromagnetic fields. If the diagnosis is suspected clinically it can be confirmed using the Quick Environmental Exposure and Sensitivity Inventory (QEESI(©)) self-questionnaire. MCS is often misdiagnosed as asthma or an allergic conditions which means that patients are frequently referred to respiratory and allergy specialists. Misdiagnosis can lead to many futile medical investigations. Psychotherapy can improve quality of life in some cases. Preventive measures are often ineffective and do not stop the condition worsening: hypersensitivity can spread to common environmental odors so that a few people become severely disabled and limited in their workplace as well as in private life. In France, 435 cases were registered in the university hospital occupational disease departments network (RNV3P) during the period 2007-2010. It is therefore important that every clinician be able to recognize the condition and ensure that their patients could get compensation when unable to go on working.

The feasibility of aromatherapy massage to reduce symptoms of Idiopathic Environmental Intolerance: a pilot study

OBJECTIVES

Idiopathic Environmental Intolerance (IEI) is an acquired disorder with multiple recurrent symptoms, which is associated with diverse environmental factors that are tolerated by the majority of people. IEI is an illness of uncertain aetiology, making it difficult to treat using conventional medicine. Therefore, there is a need for novel therapies to control the symptoms of IEI. The objective of this study was to evaluate the feasibility and impact of aromatherapy massage for individuals with IEI.

DESIGN

Non-blinded crossover trial.

SETTING

IEI patients who attended a clinic in Sapporo city were recruited, and sixteen patients were enrolled. Participants were clinically examined by an experienced medical doctor and met the criteria included in the working definition of IEI disorder.

INTERVENTIONS

During the active period, participants received four one-hour aromatherapy massage sessions every two weeks. During the control period, the participants did not receive any massages.

MAIN OUTCOME MEASUREMENTS

Scores on the IEI-scales trigger checklist, symptoms, life impact, and the State Anxiety Inventory were assessed before and after each period. Short-term mood enhancement was evaluated using the Profiles of Mood Status (POMS) before and after sessions.

RESULTS

Due to period effects, evaluation of the results had to be restricted to the first period, and the result showed no effect of intervention. All six sub-scales of the POMS improved after each session (mean score differences: 4.89-1.33, P<0.05).

CONCLUSIONS

Aromatherapy was well tolerated by subjects with IEI; however, aromatherapy, as applied in this study, did not suggest any specific effects on IEI condition.

Evaluation of the quick environmental exposure and sensitivity inventory in a Danish population

Objectives. To evaluate a Danish translation of the Quick Environmental Exposure and Sensitivity Inventory (QEESI). Methods. The study included two groups: one comprised a random sample of 2000 individuals drawn from the Danish Civil Registration System; the other comprised 315 patients with chemical intolerance. Results. The evaluation suggested good reliability for the four QEESI scales in terms of internal consistency and coefficients between test and retest scores. The discriminatory validity was the largest for the Chemical (inhalant) Intolerance and Life Impact Scales. Using combined cut-off scores for these two scales provided a sensitivity of 92.1 and a specificity of 91.8 and yielded a prevalence of 8.2% in the population group. Conclusions. The Danish translation of the QEESI showed overall good reliability and validity. We recommend the use of the combined Chemical (inhalant) Intolerance and Life Impact Scales in future studies.

Evaluation of subjective symptoms of Japanese patients with multiple chemical sensitivity using QEESI(c)

OBJECTIVES

The Quick Environment Exposure Sensitivity Inventory (QEESI(c)) has been used as a questionnaire to evaluate subjective symptoms of patients with multiple chemical sensitivity (MCS), also known as idiopathic environmental intolerance, in Japan. However, no cutoff value for Japanese subjects has yet been established. We designed this study to establish a cutoff value for Japanese subjects using QEESI(c) for screening of MCS patients.

METHODS

A questionnaire using the QEESI(c) was administered to 103 MCS patients and 309 healthy control subjects matched for age and sex. QEESI(c) scores of the two groups were compared using logistic regression analysis, receiver operating characteristic analysis, and the Mann-Whitney test.

RESULTS

Cutoff values for Japanese subjects were determined for the Chemical Intolerance subscale (40), Symptom Severity subscale (20), and Life Impact subscale (10). The subjects whose scores exceeded the cutoff values in any two subscales accounted for 88.4% of the patients but only 14.5% of the controls.

CONCLUSIONS

Our results suggest that subjects meeting two out of three subscale criteria can be screened as "patients suffering from a low level of environmental chemicals such as MCS" in Japan.

Abnormalities in cognitive-emotional information processing in idiopathic environmental intolerance and somatoform disorders

Idiopathic environmental intolerance (IEI) represents a functional somatic syndrome marked by diverse bodily complaints attributed to various substances in the environment. Evidence for abnormalities in affective information processing similar to somatoform disorders (SFD) has recently been found in people with IEI. In order to further investigate these cognitive-emotional abnormalities, we compared people with IEI (n=49), SFD only (n=43), and non-somatoform controls (n=54) with respect to their performance in the extrinsic affective Simon task (EAST). This task allowed us to dissociate indicators of automatic affective associations and emotional intrusion effects of both bodily complaints and IEI-trigger words. Negative association effects toward IEI-trigger words were strongest for IEI participants. Emotional intrusion effects of symptom words were larger both in IEI and SFD than in controls. The results of enhanced negative automatic evaluations of IEI-trigger words and greater attention allocation to symptom words support cognitive models of IEI.

Exploratory Factor Analysis With Small Sample Sizes

Exploratory factor analysis (EFA) is generally regarded as a technique for large sample sizes (N), with N = 50 as a reasonable absolute minimum. This study offers a comprehensive overview of the conditions in which EFA can yield good quality results for N below 50. Simulations were carried out to estimate the minimum required N for different levels of loadings (λ), number of factors (f), and number of variables (p) and to examine the extent to which a small N solution can sustain the presence of small distortions such as interfactor correlations, model error, secondary loadings, unequal loadings, and unequal p/f. Factor recovery was assessed in terms of pattern congruence coefficients, factor score correlations, Heywood cases, and the gap size between eigenvalues. A subsampling study was also conducted on a psychological dataset of individuals who filled in a Big Five Inventory via the Internet. Results showed that when data are well conditioned (i.e., high λ, low f, high p), EFA can yield reliable results for N well below 50, even in the presence of small distortions. Such conditions may be uncommon but should certainly not be ruled out in behavioral research data. ∗ These authors contributed equally to this work.

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.

Evidence for a specific link between the personality trait of absorption and idiopathic environmental intolerance

Absorption as a personality trait refers to the predisposition to get deeply immersed in sensory (e.g., smells, sounds, pictures) or mystical experiences, that is, to experience altered states of consciousness. Absorption is markedly related to constructs openness to experiences, hypnotic suggestibility, imagination, and dissociation. Although absorption was hypothesized to be a risk factor for medically unexplained symptoms (MUS), the construct has yet not been investigated in individually suffering from idiopathic environmental intolerance (IEI), formerly better known as multiple chemical sensitivity (MCS). IEI is a complex condition marked by MUS, which patients attribute to various chemical substances that are typically detectable by their odor (e.g., exhaust emissions, cigarette smoke). The current study investigated whether IEI was related to the personality trait of absorption. In a longitudinal study, 54 subjects with IEI were compared to 44 subjects with a somatoform disorder (SFD), but without IEI, and 54 subjects with neither SFD nor IEI (control group, CG). Self-report measures of somatic symptoms, severity of IEI, and level of absorption were collected both at a first examination and 32 mo later. On both assessments, subjects with IEI and individuals with SFD reported similar highly elevated levels of MUS, compared to CG. In contrast to SFD, IEI was specifically related to elevated absorption scores. IEI was specifically associated with a tendency to experience self-altering states of consciousness. Since absorption is related to both openness to unusual experiences and elevated imaginative involvement, absorption might contribute to IEI via two routes by (1) enhancing the susceptibility for IEI-specific convictions and (2) fostering classical conditioning processes of MUS via enhanced cognitive-imaginative representations of assumed IEI triggers.

Moderne Gesundheitssorgen und ihre Beziehung zu umweltbezogenen Beschwerden

Zusammenfassung. Theoretischer Hintergrund: Nach Petrie und Wessely (2002) bedeuten neue Technologien (z.B. Mobiltelefone und gentechnologisch veränderte Nahrungsmittel) neue Gesundheitssorgen und -beschwerden. Diese modernen Gesundheitssorgen können mittels Fragebogen standardisiert erfasst werden. Fragestellung: Es wurden die Faktorenstruktur, Reliabilität und Validität einer deutschen Übersetzung der Modern Health Worries (MHW) Scale sowie deren Beziehung zu einem funktionellen umweltbezogenen Syndrom, der Idiopathischen Umweltintoleranz (IUI), untersucht. Methode: 757 Studenten einer deutschen Universität füllten Fragebögen zur Erfassung von MHW, IUI, Krankheitsangst, Depressivität und multiplen körperlichen Beschwerden aus. Ergebnisse: Die vier Subskalen der MHW-Skala - Umweltgifte, Umweltverschmutzung, belastete Nahrungsmittel und elektrische Strahlung - konnten faktorenanalytisch bestätigt werden. Die interne Konsistenz (Cronbach’s α) der Subkalen erreichte Werte zwischen .77 und .89. MHW, negativer Affekt und Somatisierungsneigung trugen als unabhängige Prädiktoren jeweils signifikant zur Vorhersage des IUI-Beschwerdeniveaus bei. Schlussfolgerungen: Die deutsche Version der MHW-Skala kann als Messinstrument zur Verwendung für wissenschaftliche Zwecke empfohlen werden. Die Implikationen der Befunde für ein psychogenes Modell der IUI werden diskutiert.

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.

Odor annoyance of environmental chemicals: sensory and cognitive influences

In low concentrations, environment pollutants like volatile organic compounds (VOCs) may be perceived via olfaction. Modulators of odor-mediated health effects include age, gender, or personality traits related to chemical sensitivity. Severe multi-organ symptoms in response to odors also characterize a syndrome referred to as idiopathic environmental intolerance (IEI). One prominent feature of IEI is self-reported odor hypersensitivity that is usually not accompanied by enhanced olfactory functioning. The impact of interindividual differences in olfactory functioning on chemosensory perceptions is sparsely investigated, and therefore this study addressed the influences of different types of modulators, including olfactory functioning. In a psychophysical scaling experiment, an age-stratified sample of 44 males and females was examined. After controlled application of nine concentrations of six chemicals by flow-olfactometry, the participants rated four olfactory and nine trigeminal perceptions. Weak effects were found for gender and age, as well as some modulating effects of self-reported chemical sensitivity and odor discrimination ability. For chemical sensitivity, the results were as expected: Subjects with higher sensitivity reported stronger perceptions. The individual odor threshold (n-butanol) exerted no influence on the subjects' ratings of olfactory and trigeminal perceptions. Surprisingly, above-average odor discrimination ability was associated with lower ratings of odor intensity and nausea. This particular aspect of olfactory functioning might be a reflection of a more objective odor evaluation model buffering emotional responses to environmental odors.

Trauma experience in individuals with idiopathic environmental intolerance and individuals with somatoform disorders

OBJECTIVE

Results from previous studies suggest that past trauma experience increases the risk for medically unexplained somatic symptoms and somatoform disorders (SFD). This cross-sectional study examined the link between various lifetime traumas, idiopathic environmental intolerance (IEI), and SFD.

METHODS

Two clinical groups of 54 subjects with IEI and 44 subjects with SFD were compared to 54 subjects (comparison group, CG) free from both IEI and SFD regarding self-reported traumas. The subjects were mainly recruited via advertisements in local newspapers. From 970 individuals screened for IEI and multiple somatic symptoms, 152 were included through a two-step selection procedure consisting of screening questionnaires, a medical examination, and structured interviews for IEI and mental disorders.

RESULTS

In all three groups at least one potential traumatic event was reported rather frequently (CG: 70%; IEI: 82%; SFD: 73%). But contrary to our expectation, significant group differences were neither found in regard to the proportion of subjects with any trauma, nor traumas fulfilling DSM-IV criteria (CG: 41%; IEI: 48%; SFD: 59%), nor multiple traumas (CG: 43%, IEI: 56%, SFD: 39%). Only two trauma categories were endorsed more frequently by the two clinical groups than by the CG: the unspecified 'other' category (IEI, SFD>CG) and 'life-threatening illness' (IEI>CG).

CONCLUSION

No clear evidence was found for increased rates of trauma experience in IEI and SFD. However, the results of this exploratory study should be considered as preliminary. Comparing larger IEI and SFD groups with a representative population-based sample may yield different results.

Psychologische Korrelate des Multiple Chemical Sensitivity (MCS)

Zusammenfassung. Theoretischer Hintergrund: Multiple Chemische Sensitivität (MCS) ist ein Syndrom mit organisch unerklärbaren Beschwerden, die von den Betroffenen auf niedrig dosierte Umweltschadstoffe attribuiert werden. Eine Risikogruppe für MCS stellen Probanden (Pbn) mit selbstberichteter Chemischer Sensitivität (CS) dar. Fragestellung: Sind eher toxikogene oder eher psychogene Faktoren für den Bericht von MCS-Beschwerden entscheidend? Methode: Fragebogenuntersuchung an 309 Studierenden, die sich in einem mit Polychlorierten Biphenylen (PCB) belasteten Universitätsgebäude aufhielten; Querschnittstudie. Ergebnisse: Während Expositionsdauer und MCS-Syndrom nicht korrelierten, lieferten psychologische Variablen (umweltbezogene Gefährdungskognitionen, Krankheitsangst, habituelle Sorgen und Absorption) hingegen einen signifikanten Beitrag zur Vorhersage des MCS-Syndroms. Nur Pbn mit CS, aber nicht jene ohne CS, berichteten nach Aktivierung eines “Schadstoffbelastungs-Schemas“ vermehrt MCS-Beschwerden. Schlussfolgerungen: Nach den Ergebnissen dieser Querschnittsuntersuchung und anderer Studien scheinen kognitive und andere psychologische Faktoren eine bedeutsame Rolle bei der Entstehung und Aufrechtung dieses Syndroms zu spielen.