Multiple chemical sensitivity worsens quality of life and cognitive and sensorial features of sense of smell

Exposure limits for indoor volatile substances concerning the general population: The role of population-based differences in sensory irritation of the eyes and airways for assessment factors

Assessment factors (AFs) are essential in the derivation of occupational exposure limits (OELs) and indoor air quality guidelines. The factors shall accommodate differences in sensitivity between subgroups, i.e., workers, healthy and sick people, and occupational exposure versus life-long exposure for the general population. Derivation of AFs itself is based on empirical knowledge from human and animal exposure studies with immanent uncertainty in the empirical evidence due to knowledge gaps and experimental reliability. Sensory irritation in the eyes and airways constitute about 30-40% of OELs and is an abundant symptom in non-industrial buildings characterizing the indoor air quality and general health. Intraspecies differences between subgroups of the general population should be quantified for the proposal of more 'empirical' based AFs. In this review, we focus on sensitivity differences in sensory irritation about gender, age, health status, and vulnerability in people, based solely on human exposure studies. Females are more sensitive to sensory irritation than males for few volatile substances. Older people appear less sensitive than younger ones. However, impaired defense mechanisms may increase vulnerability in the long term. Empirical evidence of sensory irritation in children is rare and limited to children down to the age of six years. Studies of the nervous system in children compared to adults suggest a higher sensitivity in children; however, some defense mechanisms are more efficient in children than in adults. Usually, exposure studies are performed with healthy subjects. Exposure studies with sick people are not representative due to the deselection of subjects with moderate or severe eye or airway diseases, which likely underestimates the sensitivity of the group of people with diseases. Psychological characterization like personality factors shows that concentrations of volatile substances far below their sensory irritation thresholds may influence the sensitivity, in part biased by odor perception. Thus, the protection of people with extreme personality traits is not feasible by an AF and other mitigation strategies are required. The available empirical evidence comprising age, lifestyle, and health supports an AF of not greater than up to 2 for sensory irritation. Further, general AFs are discouraged for derivation, rather substance-specific derivation of AFs is recommended based on the risk assessment of empirical data, deposition in the airways depending on the substance's water solubility and compensating for knowledge and experimental gaps. Modeling of sensory irritation would be a better 'empirical' starting point for derivation of AFs for children, older, and sick people, as human exposure studies are not possible (due to ethical reasons) or not generalizable (due to self-selection). Dedicated AFs may be derived for environments where dry air, high room temperature, and visually demanding tasks aggravate the eyes or airways than for places in which the workload is balanced, while indoor playgrounds might need other AFs due to physical workload and affected groups of the general population.

Prevalence and correlation of multiple chemical sensitivity and electromagnetic hypersensitivity with age, sex, and depression in the Japanese population: a retrospective study

BACKGROUND

In Japan, there are currently no definitive conclusions regarding the characteristics of multiple chemical sensitivity (MCS) and electromagnetic hypersensitivity (EHS). This study aimed to determine the prevalence and correlation of MCS and EHS with age, sex, and depression in the Japanese population.

METHODS

An anonymous self-report questionnaire was distributed to 2,007 participants. Variables such as MCS, EHS, depression score, and demographic characteristics were individually evaluated using the U-test, chi-squared test, and correlation analyses. Moreover, we performed a covariance structure analysis to build a structural equation model.

RESULTS

Older individuals and women were more likely to exhibit MCS and EHS symptoms. Moreover, depression was correlated with MCS and EHS.

CONCLUSIONS

Although MCS and EHS are strongly correlated, they exhibit distinct characteristics and symptoms, indicating that they can be regarded as separate conditions.

Multiple Chemical Sensitivity Syndrome: First Symptoms and Evolution of the Clinical Picture: Case-Control Study/Epidemiological Case-Control Study

Multiple chemical sensitivity (MCS) is a chronic condition characterized by the appearance of symptoms caused by exposure to chemical compounds that are tolerable for the general population. It mainly affects middle-aged women. There are very few studies focusing on the most frequent symptoms of MCS considering age groups and gender. The main goal of this study was to find the most frequent symptoms both at the onset of the disease and at the present time describing them by age groups. The QEESI (Quick Environmental Exposure and Sensitivity Inventory) questionnaire, Scale 3 which assesses symptoms and their severity, was used as a diagnostic tool for the disease. A case-control study was conducted with the participation of 210 people. Of the cases, 94.3% were women. The symptoms that most often manifested first were airway and mucous membrane alterations (68.9%). In the development of the disease, we found cognitive alterations (OR = 31.25), heart or chest problems (OR = 22.49), neuromuscular problems (OR = 20.00) and head-related symptomatology (OR = 19.29). Identifying the most frequent pattern of symptoms by age group and sex will allow an early diagnosis of the disease to improve its prognosis and treatment.

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.

Multiple Chemical Sensitivity Syndrome: A Principal Component Analysis of Symptoms

Multiple Chemical Sensitivity (MCS) is a chronic and/or recurrent condition with somatic, cognitive, and affective symptoms following a contact with chemical agents whose concentrations do not correlate with toxicity in the general population. Its prevalence is not well defined; it mainly affects women between 40 and 50 years, without variations in ethnicity, education and economic status. We aimed to assess the core symptoms of this illness in a sample of Italian patients. Two physicians investigated different symptoms with a checklist compilation in 129 patients with MCS (117 women). We conducted a categorical Principal Component Analysis (CATPCA) with Varimax rotation on the checklist dataset. A typical triad was documented: hyperosmia, asthenia, and dyspnoea were the most common symptoms. Patients also frequently showed cough and headache. The CATPCA showed seven main factors: 1, neurocognitive symptoms; 2, physical (objective) symptoms; 3, gastrointestinal symptoms; 4, dermatological symptoms; 5, anxiety-depressive symptoms; 6, respiratory symptoms; 7, hyperosmia and asthenia. Patients showed higher mean prevalence of factors 7 (89.9%), 6 (71.7%), and 1 (62.13%). In conclusion, MCS patients frequently manifest hyperosmia, asthenia, and dyspnoea, which are often concomitant with other respiratory and neurocognitive symptoms. Considering the clinical association that is often made with anxiety, more studies are necessary on the psychosomatic aspects of this syndrome. Further analytical epidemiological studies are needed to support the formulation of aetiological hypotheses of MCS.

Impact of Odor Nuisance on Preferred Place of Residence

Context of the research: Research is increasingly carried out to take into account the social behavior of residents, the type of industry located in the area, and perceived preference for the place of residence. The quality of life in urban space is increasingly seen as a problem of cooperation between various stakeholders. These studies not only identify factors and sources of odor emissions, but also serve as the basis for creating systems to alert people living in areas adjacent to industrial areas or harmful and unpleasant industrial emissions. In recent years, environmental issues, particularly unpleasant sensory experiences, have been one of the most important acceptance criteria. Aim of the article: The aim of the study is to assess the impact of odor nuisance in the south-eastern part of Kraków (Płaszów) on the residents’ decision to leave their place of residence. In particular, the research goal was achieved to indicate which of the unpleasant odors may cause a change of residence, as well as to assess the degree of their impact on the decision to move, taking into account the social and demographic characteristics of residents. New in the article: The novelty of the work was the finding out of the residents’ opinions about the quality of life by accepting the place of residence, taking into account the aspect of odor nuisance. Previous studies on odor nuisance have focused on the emission of odors from individual plants. A novelty of this research is its implementation in an urban area, in which numerous industrial plants are located, with various odors emitted. Research methodology: To assess odor nuisance, a measuring tool developed in accordance with VDI 3883 guidelines was used, based on the latest research results on odor and noise nuisance. The questionnaire was developed based on German experience. Conclusions from the research: The data obtained as a result of the research allow us to state that specific smells are so burdensome that they may cause the necessity to leave the place of residence, because the respondents feel various unpleasant smells that have an adverse impact upon the quality of life that they perceive. A possible need for relocation of domiciles out of the current place of residence due to unpleasant smells would affect the perceptible, specific level of grief—the greater it is, the more attached the residents are to their current place of residence.

Computerized screening of G-protein coupled receptors to identify and characterize olfactory receptors

Olfactory receptors (ORs) are a group of G protein coupled receptors (GPCRs) that initiate chemical odorant signals. Although ORs are predominantly located in nasal epithelia to detect smell, these receptors are also present in peripherally in non-nasal organs/tissues. Since the quality of life and cognitive and sensorial features of sense of smell are worsened in multiple chemical sensitivity due to the interaction of ORs with offending compounds, it is important to not only differentiate these receptors from other GPCRs but also characterize these organelles to understand the underlying mechanisms of smelling disorders. The aim of this study was develop computerized programs to differentiate ORs from GPCRs. The computer program was developed on the basis of widely accepted basic algorithms. It is noteworthy that an accuracy of 95.5% was attained, a level not achieved using other established techniques for screening of ORs from GPCRs. The high accuracy rate indicates that this method of differential identification appears reliable. Our findings indicate that this novel method may be considered as a tool for identification and characterization of receptors which might aid in therapeutic approaches to human chemical-mediated sensitization.

Multiple Chemical Sensitivity: Review of the State of the Art in Epidemiology, Diagnosis, and Future Perspectives

OBJECTIVE

Systematic bibliography analysis of about the last 17 years on multiple chemical sensitivity (MCS) was carried out in order to detect new diagnostic and epidemiological evidence. The MCS is a complex syndrome that manifests as a result of exposure to a low level of various common contaminants. The etiology, diagnosis, and treatment are still debated among researchers.

METHOD

Querying PubMed, Web of Science, Scopus, Cochrane library, both using some specific MESH terms combined with MESH subheadings and through free search, even by Google.

RESULTS

The studies were analyzed by verifying 1) the typology of study design; 2) criteria for case definition; 3) presence of attendances in the emergency departments and hospital admissions, and 4) analysis of the risk factors.

OUTLOOK

With this review, we give some general considerations and hypothesis for possible future research.

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).

Repeated pulmonary exposures to zinc ions enhance inflammatory responses to subsequent metal exposures

AIM OF STUDY

Metal contaminants contribute to adverse human health effects via acute and chronic exposures. Acute metal exposures followed by prolonged secondary metal exposures may elicit exaggerated inflammatory responses in certain individuals. The aim of this study is to determine whether repeated pulmonary exposures to zinc chloride (ZnCl₂) alter subsequent responses to zinc or cerium exposures.

MATERIALS AND METHODS

Rats were intratracheally (IT) instilled with physiologic saline (n = 24) or 0.05 mg/kg ZnCl₂ (n = 16) twice weekly for 4 weeks. Four days after last dosing, the saline group was divided into three subgroups, each IT-instilled with either saline, ZnCl₂ or CeCl₃ (both at 0.1 mg/kg). The ZnCl₂ pre-instilled rats were divided into two subgroups, each instilled with 0.1 mg/kg ZnCl₂ or CeCl₃. Biomarkers of lung injury/inflammation were assessed in bronchoalveolar lavage (BAL) fluid collected 24 hours later. Oxidative stress was evaluated as total and reduced glutathione in BAL.

RESULTS

Increases in inflammatory cells, LDH, albumin, leptin, MCP-1, IP-10, fractalkine, TNFα and RANTES were observed in rats instilled with multiple PBS and then with 0.1 mg/kg ZnCl₂ and CeCl₃. However, rats pre-exposed repeatedly to 0.05 mg/kg ZnCl₂ and then challenged with 0.1 mg/kg ZnCl₂ or CeCl₃ showed even more eosinophils, lymphocytes, and increased concentrations of hemoglobin and MIP-1α. Significant reduction in GSH/GSSG ratios in BAL in response to all ZnCl₂ or CeCl₃ exposures indicated oxidative stress.

CONCLUSION

Previous exposure to zinc ions increases responsiveness to subsequent exposures to zinc and cerium ions. These findings suggest enhanced sensitization possibly due to a reduction in antioxidant defenses.

Perspectives on multisensory perception disruption in idiopathic environmental intolerance: a systematic review

PURPOSE

Multiple chemical sensitivity (MCS) also known as idiopathic environmental intolerance/illness (IEI) encompasses a cohort of subjective symptoms characterized by susceptibility to a wide spectrum of environmental compounds, causing symptoms involving various organs and a decrease in quality of life. The aim of this systematic review is to summarize evidence about MCS, with focus on indexed studies analyzing sensory pathway-related disorders.

METHODS

Medical databases were searched for English language articles related to the topic, published between 1965 and 2017 in academic, peer-reviewed journals. Particular focus was concentrated on articles depicting disturbances involving sensory organs. References of the relevant articles were examined to identify additional significant documents.

RESULTS

Fifty-eight studies were eligible for full text review. Of these, 34 studies met the selection criteria and were included in this analysis. Many variables, such as different diagnostic criteria, lack of homogeneous symptom questionnaires and the general incidence of personality traits in control subjects, biased studies as confounding factors. However, moderate evidences show that sensory pathways are somewhat altered, especially with respect to information processing in the limbic system and related cortical areas. Recent studies suggested the presence, in MCS cohorts, of attention bias, sensitization and limbic kindling, as well as recently revealed subclinical organic alterations along sensory pathways.

CONCLUSIONS

Evidences are consistent with MCS/IEI to be the result of a neural altered processing of sensorial ascending pathways, which combined with peculiar personality traits constitutes the underpinning of a multisensory condition needing multidisciplinary clinical approach.

Differences in psychological and somatic symptom cluster score profiles between subjects with Idiopathic environmental intolerance, major depression and schizophrenia

Idiopathic Environmental Intolerance (IEI) has been associated with psychogenic factors and an increased number of comorbid psychiatric disorders such as depression and anxiety disorder. The purpose of the current study was to examine a possible overlap of psychological and somatic symptoms between subjects with IEI and patients with major depression and schizophrenia as well as to specify characteristic differences. The different symptom clusters included symptoms of chemical intolerance, neurotoxicity and psychological distress as well as measurements of mental health such as anxiety, depression, somatoform symptoms, and schizophrenia-specific disturbances in cognitive domains. IEI patients reported higher overall levels in physical symptoms such as chemical intolerance, neurotoxicity and somatic symptoms not attributable to an organic cause. Schizophrenia patients showed higher overall levels in self-experienced disturbances in several schizophrenia-specific cognitive domains, whereas general psychological distress, anxiety and depression were rated highest by patients with major depression. Importantly, the groups markedly differed in the shapes of profiles of various symptom clusters. Our results provide evidence that IEI patients can be distinguished on the phenomenological level from patients with major depression or schizophrenia, and that distinct domains of psychological and somatic symptoms are particularly problematic in specific diagnostic groups.