Metagenomic gut microbiome analysis of Japanese patients with multiple chemical sensitivity/idiopathic environmental intolerance.

BACKGROUND: Although the pathology of multiple chemical sensitivity (MCS) is unknown, the central nervous system is reportedly involved. The gut microbiota is important in modifying central nervous system diseases. However, the relationship　between the gut microbiota and MCS remains unclear. This study aimed to identify gut microbiota variations associated with MCS using shotgun metagenomic sequencing of fecal samples. METHODS: We prospectively recruited 30 consecutive Japanese female patients with MCS and analyzed their gut microbiomes using shotgun metagenomic sequencing. The data were compared with metagenomic data obtained from 24 age- and sex-matched Japanese healthy controls (HC). RESULTS: We observed no significant difference in alpha and beta diversity of the gut microbiota between the MCS patients and HC. Focusing on the important changes in the literatures, at the genus level, Streptococcus, Veillonella, and Akkermansia were significantly more abundant in MCS patients than in HC (p < 0.01, p < 0.01, p = 0.01, respectively, fold change = 4.03, 1.53, 2.86, respectively). At the species level, Akkermansia muciniphila was significantly more abundant (p = 0.02, fold change = 3.3) and Faecalibacterium prausnitzii significantly less abundant in MCS patients than in HC (p = 0.03, fold change = 0.53). Functional analysis revealed that xylene and dioxin degradation pathways were significantly enriched (p < 0.01, p = 0.01, respectively, fold change = 1.54, 1.46, respectively), whereas pathways involved in amino acid metabolism and synthesis were significantly depleted in MCS (p < 0.01, fold change = 0.96). Pathways related to antimicrobial resistance, including the two-component system and cationic antimicrobial peptide resistance, were also significantly enriched in MCS (p < 0.01, p < 0.01, respectively, fold change = 1.1, 1.2, respectively). CONCLUSIONS: The gut microbiota of patients with MCS shows dysbiosis and alterations in bacterial functions related to exogenous chemicals and amino acid metabolism and synthesis. These findings may contribute to the further development of treatment for MCS. TRIAL REGISTRATION: This study was registered with the University Hospital Medical Information Clinical Trials Registry as UMIN000031031. The date of first trial registration: 28/01/2018.

Combined Neurological Syndrome in Electrohypersensitivity and Multiple Chemical Sensitivity: A Clinical Study of 2018 Cases.

From a cohort of 2018 evaluable consecutive cases issued from the European Clinical Trial Database, we describe the complete clinical symptomatic presentation of electrohypersensitivity (EHS) and multiple chemical sensitivity (MCS) and their association in the framework of a unique, sensitivity-related environmental neurologic syndrome. Eligibility criteria are those of the Atlanta consensus meeting for MCS, and those of WHO for EHS. There were 1428 EHS, 85 MCS and 505 EHS/MCS evaluable cases, so EHS was associated with MCS in 25%. Women appeared to be much more susceptible to EHS and/or to MCS than men, with no statistical significance between the EHS and MCS groups (p = 0.07), but the combined group revealed a more significant female sex ratio of 80.4% (p < 0.0001). All symptoms except emotional behavior were significantly more frequent in EHS patients than in healthy controls (p < 0.0001). We found no pathognomonic symptoms to establish the diagnosis of both disorders or to distinguish EHS from MCS. The three groups of patients were found to share identical symptoms, while several symptoms were found to be more significantly frequent in EHS/MCS than in EHS (p < 0.0001). From these data, we suggest that EHS and MCS are new brain disorders, generated via a common etiopathogenic mechanism.

Sensibilidad química múltiple en una niña de 8 años. Seguimiento durante 6 años / Multiple chemical sensitivity in an 8-year-old girl. A 6-year follow-up

La sensibilidad química múltiple (SQM) es una entidad escasamente comprendida y controvertida. La SQM es un síndrome polisintomático y multisistémico. Los sujetos con SQM muestran una sintomatología compleja debido a la intolerancia a los agentes químicos. Los síntomas incluyen malestar general, inestabilidad cardiovascular, irritación de órganos de los sentidos, desórdenes respiratorios, con hipersensibilidad que afecta a piel, recubrimiento epitelial de intestino, garganta y pulmones. Se presenta un caso de una mujer de 8 años, valorada por sensibilización química con síntomas inhalatorios y faríngeos, conjuntivitis, disfonía y accesos de tos con sensación de dificultad respiratoria. El seguimiento se ha realizado durante 6 años, durante los cuales se ha repetido el test inhalatorio en dos ocasiones con los mismos resultados concluyentes para el diagnóstico de SQM. El caso comunicado reúne los criterios de SQM, siendo excepcional el inicio de los síntomas a una edad tan temprana. (AU)

Multiple chemical sensitivity (MCS) is a controversial little understood entity. MCS is a multisystem and poly-symptomatic syndrome. MCS subjects display a complex symptomatology due to the intolerance of chemical agents. Symptoms include general discomfort, cardiovascular instability, sensory organs irritation, breath disorders, hypersensitivity affecting the skin and epithelial lining of the gut, throat and lungs. We report the case of an 8 years old female, assessed in medical consultation for chemical sensitization when presenting inhalation and pharyngeal symptoms, conjunctivitis, dysphonia, coughing spells and respiratory distress. A 6-year follow-up was carried out and the provocation inhaler test which was performed twice among that period obtained the same conclusive results for the diagnosis of MCS. The case submitted meets the criterion of MCS, being exceptional a debut of the symptons at such an early age. (AU)

Multiple Chemical Sensitivity/Idiopathic Environmental Intolerance: A Practical Approach to Diagnosis and Management.

Patients with multiple chemical sensitivity, now called idiopathic environmental intolerance, frequently present to clinical immunologists and allergists for diagnosis and treatment. Patients report a plethora of respiratory and multisystem problems attributed to a wide variety of unrelated, otherwise non-noxious, triggers. They may go to extreme, often seemingly bizarre lengths to avoid contact with everyday exposures and may become housebound, unable to work or function socially. Often beginning with exposure to odors, triggers can multiply to involve foods, clothing, medications, and even electromagnetic radiation. The condition cannot be explained by IgE-mediated or other immune processes, and clinical immunologists and allergists may feel unprepared to care for such patients. In this article, a paradigm to understand the probable mechanisms underlying this condition and a practical approach to diagnosis and management will be presented.

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.

Prevalence of Migraine Disease in Electrohypersensitive Patients.

BACKGROUND: The vast majority of electrohypersensitive (EHS) patients present headaches on contact with an electromagnetic source. Clinical features suggest that the headaches of these patients could be a variant of the migraine disease and could be treated as such. We aimed to assess the prevalence of migraine disease in EHS patients using a validated questionnaire. METHODS: Patients with EHS defined according to WHO criteria were contacted through EHS patient support associations. They were required to answer a self-questionnaire including clinical data and the extended French version of the ID Migraine questionnaire (ef-ID Migraine) to screen for the migraine disease. Migraine prevalence and its 95% confidence interval (CI) were reported. Patients' characteristics, symptoms (rheumatology, digestive, cognitive, respiratory, cardiac, mood, cutaneous, headache, perception, genital, tinnitus and tiredness) and impact on daily life were compared between migraineur and non-migraineur patients. RESULTS: A total of 293 patients were included (97% women, mean age 57 ± 12 years). Migraine was diagnosed in 65% (N = 191; 95% CI: 60-71%) with the ef-ID Migraine. The migraine diagnosis was accompanied by nausea/vomiting in 50% of cases, photophobia in 69% or visual disturbances in 38%. All of the 12 symptoms assessed were of higher intensity in migraineurs than in non-migraineurs. The symptoms prevented social life in 88% of migraineurs and 75% of non-migraineurs (p < 0.01). CONCLUSIONS: Our work encourages us to consider the headaches of these patients as a possible variant of the migraine disease and, possibly, to manage them according to the current recommendations.

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.

Laboratory Test Results in Patients with Workplace Moisture Damage Associated Symptoms-The SAMDAW Study.

The mechanisms of health effects of moisture damage (MD) are unclear, but inflammatory responses have been suspected. The usefulness of laboratory and allergy tests among patients in secondary healthcare with symptoms associated with workplace MD were examined. Full blood count, erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), total serum immunoglobulin E (IgE), fractional exhaled nitric oxide (FeNO), and skin prick testing were assessed and analyzed in relation to multiple chemical sensitivity (MCS) and perceived stress in 99 patients and 48 controls. In analysis, t-tests, Mann-Whitney tests, and chi-squared tests were used. Minor clinically insignificant differences in blood counts were seen in patients and controls, but among patients with asthma an elevated neutrophil count was found in 19% with and only in 2% of patients without asthma (p = 0.003). CRP levels and ESR were low, and the study patients' FeNO, total IgE, or allergic sensitization were not increased compared to controls. The level of stress was high among 26% of patients and 6% of controls (p = 0.005), and MCS was more common among patients (39% vs. 10%, p < 0.001). Stress or MCS were not significantly associated with laboratory test results. In conclusion, no basic laboratory or allergy test results were characteristic of this patient group, and neither inflammatory processes nor allergic sensitization were found to explain the symptoms among these patients. While the value of basic laboratory tests should not be ignored, the use of allergy tests does not seem necessary when symptoms are indicated to be workplace-related.

Impact of comorbidity on symptomatology in various types of environmental intolerance in a general Swedish and Finnish adult population.

Comorbidity with various health conditions is common in environmental intolerances (EIs), which restricts understanding for what symptoms that are associated with the intolerance per se. The present objectives were to study (i) prevalence of a broad range of specific symptoms in chemical, building-related, electromagnetic field- (EMF) related, and sound EI, irrespective of comorbidity, (ii) prevalence of symptoms in body systems in exclusive EIs, and (iii) increased risk of symptoms in body systems in exclusive EIs that cannot be referred to functional somatic syndromes, inflammatory diseases or mental disorders. Cross-sectional data (n = 4941) were used from two combined population-based surveys, the Västerbotten (Sweden) and Österbotten (Finland) Environmental Health Studies. Categorization of EI cases and controls were based on self-reports. Symptoms were assessed with the Environmental Hypersensitivity Symptom Inventory, and these were converted to 27 symptoms of the International Classification of Primary Care, 2nd edition, in eight chapters of body systems. The results showed, with few exceptions, that all assessed specific symptoms were significantly more prevalent in all four EIs than in referents. Although a large overlap between EIs, characteristic body system symptoms were eye and respiratory symptoms in chemical and building-related intolerance, skin symptoms in EMF-related intolerance, and general and unspecified, digestive, eye, cardiovascular, neurological, and psychological symptoms in sound intolerance. After controlling for various comorbidities, all studied body system symptoms were positively associated with chemical intolerance, fewer with sound intolerance, only one with building-related intolerance, and none with EMF-related EI. In conclusion, a broad range of symptoms are reported in all four EIs implying common mechanisms, but symptoms of certain body systems are more likely to be reported in a certain EI that cannot be explained by comorbidity.

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.

Undertreatment with Osimertinib in patient with multiple chemical sensitivity. A case report.

Introduction: Multiple chemical sensitivity (MCS), is a syndrome characterised by increased sensitivity to the exposure of environmental chemicals (1). There are considerable difficulties in reaching a good estimate of the prevalence of disease and the main pathogenetic hypotheses take into account both the organic and psychiatric/psychological factors. Treatment with epidermal growth factor tyrosine kinase receptor inhibitors (tkis), like Osimertinib, results in improved progression-free survival (PFS) compared to chemotherapy, in Non-small-cell lung carcinoma (NSCLC) with epidermal growth factor receptor (EGFR) mutation (2). Case report: We describe the case of a 74 year old woman with history of MCS and fibromyalgia in treatment with Osimertinib for EGFR-mutated NSCLC. Patient initially refused any form of active therapy for lung cancer, but thanks to teamwork and the important support of the psychologist, the patient decided to start treatment with Osimertinib at a reduced dose, not 80 mg but 40 mg. Subsequently, after few days , of his own free will and without informing the staff physicians, the patient changed the treatment schedule by taking one quarter of the dose of the medicine every other day, justifying this choice in therapeutic modification because of her fear and intolerance to any type of medicine and/ or chemical substance, being influenced by MCS. Management & outcome: Despite the changes in the treatment plan, a PET scan performed after two months showed a sigificative lung response and the stability of bone metastases. Discussion. Our case describes a significative response with Osimertinib despite the change in dosage and schedule in a patient with MCS. Our experience deserves to be considered in the light of its particularity and uniqueness as it shows an excellent response to treatment with Osimertinib despite the change made to the dosage and schedule, in a patient presenting in her medical history this rare pathological condition: MCS syndrome.

A First Urological Approach to the Genitourinary Manifestations of Multiple Chemical Sensitivity. Systematic Review.

INTRODUCTION AND OBJECTIVES: Multiple chemical sensitivity (MCS) is a complex disease with multiorgan manifestations, some of which are still poorly understood, such as genitourinary manifestations. The objective of this article is to review these genitourinary manifestations. MATERIAL AND METHODS: A retrospective descriptive study on the genitourinary manifestations described in patients with multiple chemical sensitivity is performed, based on a systematic review of the literature between February 1956 and December 2020, consulting the Medline/PubMed database and the Google search engine. Descriptive statistics of the variables studied were performed with frequency and percentage for qualitative variables and median and range (minimum-maximum value) for quantitative variables. RESULTS: We reviewed the originals or abstracts of 3450 articles on MCS, including 461 on symptoms (13.3%) and selecting 40 (1.1%) that referred to genitourinary pathologies or symptoms and corresponded to 19 reviews, 14 articles on case reports (11 clinical cases and 3 series), 5 books with case reports, 1 consensus document and 1 update. The number of patients with MCS studied in these 40 articles was 4556 of whom 303 presented genitourinary symptoms (6.6%), and corresponded to 277 women (91.4%) and 27 men (8.6%) with a mean age of 39.4 years, range (7-82 years). There were 119 different genitourinary symptoms or pathologies with 170 citations which in frequency were 77 for gynecological symptoms (45.3%) in 28 publications (70%), 62 for urological symptoms (36.5%) in 29 publications (72.5%), 18 for sexological symptoms (10.6%) in 8 publications (20%) and 13 for andrological symptoms (7.6%) in 5 publications (12.5%). CONCLUSIONS: Genitourinary manifestations of MCS are rare and predominantly in women. They constitute a genitourinary syndrome including gynecological, urological, sexological and andrological symptoms. Until today there has been no study of these symptoms in the medical literature.

A First Urological Approach to the Genitourinary Manifestations of Multiple Chemical Sensitivity. Systematic Review

Introduction and Objectives: Multiple chemical sensitivity (MCS) is a complex disease with multiorgan manifestations, some of which are still poorly understood, such as genitourinary manifestations. The objective of this article is to review these genitourinary manifestations. Material and Methods: A retrospective descriptive study on the genitourinary manifestations described in patients with multiple chemical sensitivity is performed, based on a systematic review of the literature between February 1956 and December 2020, consulting the Medline/PubMed database and the Google search engine. Descriptive statistics of the variables studied were performed with frequency and percentage for qualitative variables and median and range (minimum-maximum value) for quantitative variables. Results: We reviewed the originals or abstracts of 3450 articles on MCS, including 461 on symptoms (13.3%) and selecting 40 (1.1%) that referred to genitourinary pathologies or symptoms and corresponded to 19 reviews, 14 articles on case reports (11 clinical cases and 3 series), 5 books with case reports, 1 consensus document and 1 update. The number of patients with MCS studied in these 40 articles was 4556 of whom 303 presented genitourinary symptoms (6.6%), and corresponded to 277 women (91.4%) and 27 men (8.6%) with a mean age of 39.4 years, range (7-82 years). There were 119 different genitourinary symptoms or pathologies with 170 citations which in frequency were 77 for gynecological symptoms (45.3%) in 28 publications (70%), 62 for urological symptoms (36.5%) in 29 publications (72.5%), 18 for sexological symptoms (10.6%) in 8 publications (20%) and 13 for andrological symptoms (7.6%) in 5 publications (12.5%). Conclusions: Genitourinary manifestations of MCS are rare and predominantly in women (AU)

Physiological Health and Physical Performance in Multiple Chemical Sensitivity-Described in the General Population.

Multiple chemical sensitivity (MCS) is a multifactorial somatic disorder characterized by physical reactions triggered by even extremely low levels of different airborne chemicals. In most individuals with MCS, these reactions have substantial negative impact on social, occupational, and everyday life often including limited or no engagement in physical activities. The aim of this study was to explore associations between MCS and objective measurements of anthropometry, cardiorespiratory health, and physical performance. From the Danish population-based cohort DanFunD counting 9656 participants aged 18-76 years, 1.95% (n = 188) were categorized as MCS individuals (MCS All). Of those 188, 109 participants were subcategorized as having MCS without functional somatic disorders (FSD) (MCS with no comorbid FSD). The remaining study population without any FSD were regarded controls. We used adjusted multiple linear regression analyses to evaluate associations between MCS and anthropometry, cardiorespiratory fitness, and physical performance. Compared with the general population, MCS All had less optimal body composition, increased risk of obesity, impaired cardiorespiratory fitness, and physical performance which was not seen in MCS with no comorbid FSD. MCS individuals may be inhibited to maintain an active lifestyle which can increase risk of obesity and consequently have negatively impact on general health, which may not be the case among MCS with no comorbid FSD.

Exploring the contributing factors to multiple chemical sensitivity in patients with migraine.

OBJECTIVE: Multiple chemical sensitivity (MCS) is a form of chemical intolerance in which various systemic symptoms are triggered by exposure to a variety of chemical substances. Although migraine has been associated with central sensitivity syndrome, the relationship between MCS and migraine has not been studied. We assessed the frequency of MCS and its related factors in patients with migraine. METHODS: We performed a cross-sectional study that included 95 patients (14 M/81 F; age, 45.4 ± 12.4 years) out of 100 consecutive patients with migraine from our outpatient headache clinic. MCS was defined as having a combination of Q1 ≥ 30, Q3 ≥ 13, and Q5 ≥ 17 on the quick environment exposure sensitivity inventory (QEESI; Japanese version). Central sensitization inventory-A scores >40 were considered an indication of central sensitization. Headache-related disability and psychological distress were evaluated with the Migraine Disability Assessment score (MIDAS) and Kessler Psychological Distress Scale (K6), respectively. RESULTS: MCS was identified in 20% of patients with migraine; however, none had previously been diagnosed with MCS. The MCS-positive group had higher rates of photophobia, osmophobia, visual aura, sensory aura, and central sensitization and higher MIDAS and K6 scores than the MCS-negative group. A logistic regression analysis showed that osmophobia, sensory aura, and central sensitization were significant contributors to MCS. CONCLUSION: We showed that MCS was observed in 20% of patients with migraine, and our study results may indicate a possible association of MCS with central sensitization and hypersensitivity-related symptoms in patients with migraine.

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 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.

Insulin Resistance Is Associated with Multiple Chemical Sensitivity in a Danish Population-Based Study-DanFunD.

Multiple chemical sensitivity (MCS) is a multisystem syndrome, and limited knowledge of its pathophysiology exists. Based on the population-based Danish cohort DanFunD, this study investigated metabolic health in people with MCS compared to individuals who did not have MCS. From 9656 cohort participants aged 18-76 years old, 1.95% were categorized as MCS individuals with comorbid functional somatic disorders (MCS +FSD, n = 188), and 1.13% were categorized as MCS without functional somatic disorders (MCS ÷FSD, n = 109). MCS was characterized based on three criteria: the experience of symptoms upon exposure to common odors and airborne chemicals, symptoms related the central nervous systems and others organ symptoms, and significant impact on every day, social, and occupational life. The remaining study population without MCS or any other functional somatic disorders were regarded as controls. We used adjusted multiple linear regression with link-function to evaluate the associations between lipid and glucose metabolism markers and MCS. We also tested the odds ratio of metabolic syndrome in MCS. Results did not point to statistically significant associations between lipid biomarkers or metabolic syndrome and both MCS groups compared to the controls. We found that MCS individuals may be more insulin resistant and that MCS ÷ FSD may have an impaired glucose metabolism when compared to controls.