Examine the public health impacts of functional somatic disorders using the DanFunD study.

Background: Persistent physical symptoms (e.g. pain, fatigue) are prevalent in the population and some persons may develop a functional somatic disorder (FSD). We still need to explore the limits between general bodily sensations and FSD, and great controversies exist as regard delimitation, occurrence, risk factors, prognosis, and costs of FSD in the general population. This is mainly due to the lack of focused, sufficient powered, population-based epidemiological studies. Material and Methods: The DanFunD study is the largest focused population-based study on FSD and has the potential to answer these crucial questions regarding the FSD disorders. DanFunD has its origin in the Copenhagen area of Denmark and was initiated in 2009 by an interdisciplinary team of researchers including basic scientists, clinical researchers, epidemiologists, and public health researchers. A population-based cohort of nearly 10,000 people have filled in detailed questionnaires, gone through a thorough health examination, and a biobank is established. The cohort was re-examined after five years. Results:The prevalence of FSD in the Danish population is about 10-15% and is twice as common in women as in men. Persons with FSD report impaired daily activities and low self-perceived health, which qualifies FSD as a major public health problem. The research plan to unravel the risk factors for FSD employs a bio-psycho-social approach according to a detailed plan. Preliminary results are presented, and work is in progress. Likewise, plans for assessing prognosis and health care costs are provided. Conclusion: We invite researchers in the field to collaborate on this unique data material.

A randomised, placebo-controlled trial of transcranial pulsed electromagnetic fields in patients with multiple chemical sensitivity.

OBJECTIVE: To evaluate the efficacy of transcranially applied pulsed electromagnetic fields (PEMF) on functional impairments and symptom severity in multiple chemical sensitivity (MCS) patients. METHODS: The study was conducted as a nationwide trial in Denmark using a randomised, parallel-group, double-blind and placebo-controlled design. Sample size was estimated at 40 participants. Eligibility criteria were age 18-75 years and fulfilment of the MCS case criteria. Participants received either PEMF or placebo PEMF (no stimulation) applied transcranially for 6 weeks. The primary outcome was the Life Impact Scale (LIS) of the Quick Environmental Exposure and Sensitivity Inventory (QEESI). Secondary outcomes were the Symptom Severity Scale (SSS) and the Chemical Intolerance Scale of QEESI. RESULTS: A total of 39 participants were randomised to PEMF or placebo treatment. No significant difference was observed on QEESI LIS between groups with a mean change score of -5.9 in the PEMF group compared with -1.5 in the placebo group (p=0.35, effect size=-0.31). However, a significant decrease was detected on QEESI SSS within and between groups with a mean change score of -11.3 in the PEMF group compared with -3.2 in the placebo group (p=0.03, effect size=-0.60). CONCLUSION: PEMF treatment of 6 weeks showed no effect on functional impairments in MCS. However, a significant decrease in symptom severity was observed.

Gastrointestinal symptoms related to the irritable bowel syndrome - a longitudinal population-based register study.

OBJECTIVE: Functional gastrointestinal (GI) symptoms can develop into persistent states often categorised as the irritable bowel syndrome (IBS). In the severe end of the GI symptom continuum, other coexisting symptoms are common. We aimed to investigate the GI symptom continuum in relation to mortality and development of GI diseases, and to examine if coexisting symptoms had an influence on the outcomes. MATERIAL AND METHODS: A longitudinal population-based study comprising two 5-year follow-up studies: Dan-Monica1 (1982-1987) and Inter99 (1999-2004). IBS was defined according to a population-based IBS definition. The pooled cohort (n = 7278) was followed until December 2013 in Central Registries. RESULTS: Fifty-one percent had no GI symptoms, 39% had GI symptoms but never fulfilled the IBS definition, 8% had fluctuating IBS and 2% had persisting IBS. There was no significant association between symptom groups and mortality (p = 0.47). IBS and GI symptoms with abdominal pain were significantly associated with development of GI diseases. Only GI symptoms with abdominal pain were associated with development of severe GI diseases (HR: 1.38; 95% CI: [1.06-1.79]). There were no statistically significant interactions between symptom groups and coexisting symptoms in relation to the two outcomes. CONCLUSIONS: GI diseases were seen more frequently, but IBS was not associated with severe GI diseases or increased mortality. Clinicians should be more aware when patients do not fulfil the IBS definition, but continue to report frequent abdominal pain. Coexisting symptoms did not influence mortality and development of GI diseases.

Chemosensory perception, symptoms and autonomic responses during chemical exposure in multiple chemical sensitivity.

PURPOSE: Multiple chemical sensitivity (MCS) is a prevalent medically unexplained symptom characterized by symptom reactions to everyday chemical exposure below hygienic thresholds. The aim of this study was to investigate the expressions of hyper-reactivity in MCS during whole-body exposure to low concentrations of the odorant n-butanol. METHODS: We exposed 18 participants with MCS and 18 non-ill controls to a low concentration of the odorant n-butanol using an exposure chamber. The first 10 min constituted blank exposure, after which the n-butanol concentration increased and reached a plateau at 11.5 mg/m(3). RESULTS: MCS participants, compared with controls, reported greater perceived odor intensities, more unpleasantness to the exposure and increasing symptoms over time. MCS participants also expressed higher pulse rate and lower pulse rate variability than controls did. No group differences were found for breathing rate or tonic electrodermal activity responses. CONCLUSIONS: We conclude that MCS sufferers differ from healthy controls in terms of autonomic responses, symptoms and chemosensory perception during chemical exposure.

Factors affecting implementation of mindfulness in hospital settings: A qualitative meta-synthesis of healthcare professionals' experiences.

Background: Researchers have found that mindfulness-based interventions can reduce stress and improve mental health in healthcare professionals, as well as support relationship building, communication, and compassionate care. However, few researchers have systematically examined what determines successful implementation in hospital settings, which is essential for integrating research in clinical practice. Objectives: The aim of this study was to synthesize qualitative data regarding healthcare professionals' experiences of factors affecting implementation of mindfulness in hospital settings and outline recommendations for clinical practice. Design: A systematic review and meta-synthesis of qualitative studies. Data sources: A systematic search was conducted in six databases; Scopus, PubMed, CINAHL, PsycINFO (Ovid), Web of Science, and ProQuest Dissertations and Theses Global. The inclusion criteria were: 1) Healthcare professionals engaged in patient care in hospital settings, 2) Mindfulness-based interventions defined by Crane and colleagues', and 3) Primary studies using a qualitative design. Review methods: Multiple researchers were engaged in screening, quality assessment, data extraction, and interpretation of the results. Thematic synthesis described by Thomas and Harden guided the data analysis. Reporting followed Enhancing Transparency in Reporting the Synthesis of Qualitative Research (ENTREQ). Results: Eighteen studies were included. We identified three overall themes of importance for successful implementation: 1) Buying In, 2) Allocating time and space, and 3) Keeping it going. The results revealed that cultural values, held beliefs about mindfulness, inter-professional relationships, and context-related factors such as time and space could affect implementation of mindfulness in hospital settings. Conclusion: Based on the results, we formulated eight recommendations to guide stakeholders and hospital management in planning implementation of mindfulness in hospital settings. However, to confirm the results, more research where mindfulness implementation is the primary aim is needed.

The influence of mindfulness-based stress reduction on the work life of healthcare professionals - A qualitative study.

BACKGROUND: and purpose: Quantitative studies show that mindfulness-based interventions can reduce stress and burnout in healthcare professionals. Few qualitative studies have explored healthcare professionals' experiences with mindfulness training. The aim of the study was to explore healthcare professionals' experiences of how attending a course in Mindfulness-Based Stress Reduction influenced their work life, including their relationship with patients and colleagues. METHODS: Fifty-six healthcare professionals attended a Mindfulness-Based Stress Reduction course between January and June 2022. Participant observation followed by six semi-structured focus group interviews and 15 individual interviews were conducted. Data were collected in a cardiology department and in an obstetrics and gynaecology department. Thematic data analysis was performed. Reporting followed COREQ guidelines. RESULTS: Six themes were identified: 1) Allowing a pause and focusing on one thing at a time, 2) Awareness of the freedom to choose, 3) The need for self-compassion, as a prerequisite for taking care of others, 4) The value of presence and calmness in patient encounters, 5) Awareness of how stressful behavior affects oneself and others, 6) The value of practicing mindfulness with colleagues. CONCLUSION: This study suggests that offering Mindfulness-Based Stress Reduction to healthcare professionals can start a positive process of change from a tendency to neglect personal needs to becoming more compassionate towards oneself and others. Mindfulness training may thus prevent burnout and lead to a more compassionate workplace culture that also manifests in better patient care. However, a collective understanding and knowledge of mindfulness in the work setting may be necessary to sustain these changes.

Social economic factors and the risk of multiple chemical sensitivity in a Danish population-based cross-sectional study: Danish Study of Functional Disorders (DanFunD).

OBJECTIVES: Multiple chemical sensitivity (MCS) is a rare multisystem and poly-symptomatic disease characterised by a report of various somatic symptoms attributed to inhalation of volatile chemicals in usually harmless doses. The aim was to explore four selected social factors and the risk of MCS in the general Danish population. DESIGN: A cross-sectional general population-based study. SETTING: The Danish Study of Functional Disorders was conducted from 2011 to 2015 which included 9656 participants. PARTICIPANTS: A total of 8800 participants were included in analyses after observations with missing data on exposure and/or outcome were excluded. A total of 164 cases fulfilled the questionnaire criteria for MCS. Of the 164 MCS cases, 101 reported no comorbid functional somatic disorder (FSD) and were included in a subgroup analysis. A total of 63 MCS cases fulfilled the criteria for at least one additional FSD, this subgroup was not included in further analysis. The remaining study population without MCS or any FSD were regarded as controls. OUTCOME MEASURES: We used adjusted logistic regression to calculate OR and 95% CIs of MCS and MCS without FSD comorbidities for each social variable separately including education, employment, cohabitation and subjective social status. RESULTS: We found an increased risk of MCS among the unemployed (OR: 2.95, 95% CI: 1.75 to 4.97), and a twofold increased risk of MCS among individuals with low subjective social status (OR: 2.00, 95% CI: 1.08 to 3.70). At the same time, 4 years or more of vocational training were protective of MCS. No significant associations were observed among MCS cases with no comorbid FSD. CONCLUSION: Lower socioeconomic status was found to be associated with a higher risk of having MCS but not with MCS without FSD comorbidities. Due to the cross-sectional design of the study, we cannot determine whether social status is a determinant or a consequence of MCS.

The association between idiopathic environmental intolerance and psychological distress, and the influence of social support and recent major life events.

OBJECTIVES: Idiopathic environmental intolerance (IEI) is a disorder characterized by non-specific symptoms attributed to common airborne chemicals. Increasing evidence points to an association between IEI and symptoms of psychological distress. However, whether other risk factors influence this association has not been clarified. The objective of this study was to examine the association between psychological distress and IEI and to determine whether the association is confounded by social support and major life events. METHODS: Data were collected by postal questionnaires; other results from the study have been published previously in this journal. The study included participants from a general population-based study who had reported symptoms of chemical sensitivities (n = 787) and two patient groups. The first patient group (n = 101) included individuals who had contacted the Danish Research Centre for Chemical Sensitivities, and the second included individuals who had been diagnosed with environmental intolerance (n = 136). Multiple, hierarchical linear regression analyses were conducted with four IEI-related domains, i.e., mucosal and CNS symptoms, chemical intolerances and social consequences, as the dependent variables, and psychological distress, social support and major life events as the independent variables. RESULTS: Our study confirmed positive and statistically significant associations between psychological distress and IEI. The associations remained statistically significant after adjusting for major life events and social support. CONCLUSIONS: The results suggest that the association between IEI and psychological distress cannot be explained by known risk factors. More studies, including longitudinal studies, are needed to determine the role of psychological distress in the development and course of IEI.

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.

Conditioned pain modulation and pain sensitivity in functional somatic disorders: The DanFunD study.

BACKGROUND: Disrupted pain regulation has been proposed as a component in functional somatic disorders (FSD). The objective of this study was to examine a general population sample, encompassing three delimitations of FSD while assessing pain sensitivity and conditioning pain modulation (CPM). METHODS: Pressure pain thresholds (PPTs) at the tibialis and trapezius muscles were recorded at baseline. During cold pressor stimulation of the hand, the tibialis PPTs were re-assessed and the difference from baseline measures defined the CPM effect. Participants (n = 2,198, 53% females) were randomly selected from the adult Danish population. FSD was established by self-reported symptom questionnaires. RESULTS: With a few exceptions, only weak associations were seen between PPTs and CPM in cases with FSD (p > .1). A high PPT was associated with lower odds of having multi-organ bodily distress syndrome (ORPPT trapezius : 0.66, 95% CI: 0.49-0.88, p = .005), with the symptom profile characterized by all symptoms (ORPPT trapezius : 0.72, 95% CI: 0.58-0.90, p = .003 and ORPPT tibialis : 0.75, 95% CI: 0.62-0.91, p = .004), and with multiple chemical sensitivity (ORPPT trapezius : 0.81, 95% CI: 0.67-0.97, p = .022). High CPM was associated with high odds of having irritable bowel (ORCPM relative : 1.22, 95% CI: 1.04-1.43, p = .013 and ORCPM absolute  = 2.66, 95% CI: 1.07-6.45, p = .033). CONCLUSION: However, only PPT measured over the trapezius muscle were still significant after correction for multiple testing for the symptom profile characterized by all symptoms. Findings from this study do not support altered pain regulation in questionnaire-based FSD which is in contrast with the existing presumption. Further epidemiological studies in this field are needed. SIGNIFICANCE: Disrupted pain regulation as measured by abnormal pain thresholds has been hypothesized as a central mechanism in Functional Somatic Disorders (FSD). The hypothesis has been raised in clinical setting where patients presented subjective and objective features of hypersensitivity. The present population-based study does not support this notion. This points to the importance of further studies into the underlying pathophysiology mechanisms of FSD.

Multiple chemical sensitivity described in the Danish general population: Cohort characteristics and the importance of screening for functional somatic syndrome comorbidity-The DanFunD study.

BACKGROUND: Multiple chemical sensitivity (MCS) is characterized by widespread symptoms attributed to exposure to airborne chemicals. MCS is categorized as a functional somatic syndrome (FSS), and MCS cases often meet the criteria for other types of FSS, e.g. fibromyalgia. The primary aim was to characterize MCS regarding symptom triggers, symptoms, lifestyle and describe demographics, socioeconomics and lifestyle factors associated with MCS. A secondary aim was to examine the implication of FSS comorbidity. METHODS: Data were derived from a random sample of the Danish adult population enrolled in the Danish Study of Functional Disorders (DanFunD; n = 9,656). Questionnaire data comprised information used to delimit MCS and four additional types of FSS, as well as data on demographics, socioeconomics and lifestyle. MCS cases (n = 188) was stratified into subgroups; MCS only (n = 109) and MCS with comorbid FSS (n = 73). Information regarding FSS comorbidities were missing for six MCS cases. MCS subgroups and controls without FSS comorbidities (n = 7,791) were compared by means of logistic regression analyses, adjusted for age and sex. RESULTS: MCS was associated with female sex, not being in occupation and low social status, but not with age or education. MCS cases reported normal dietary intake and smoking habits and lower alcohol consumption. Additional associations were found between MCS and low rate of cohabitation, sedentarism, daily physically limitations, and poor quality of sleep. However, subgroup analysis revealed that these findings were primarily associated with MCS with comorbid FSS. CONCLUSIONS: MCS was associated with lower socioeconomic status, physically inactivity and poor quality of sleep. Subgroup analysis revealed that several associations was explained by FSS comorbidity, i.e. MCS cases with no comorbid FSS showed normal rate of cohabitation and did not report physical limitations or difficulties sleeping. Overall, our findings emphasise the importance of screening MCS cases for FSS comorbidity both in epidemiological and clinical settings.

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.

Repressive coping and alexithymia in idiopathic environmental intolerance.

OBJECTIVE: To examine if the non-expression of negative emotions (i.e., repressive coping) and differences in the ability to process and regulate emotions (i.e., alexithymia) is associated with idiopathic environmental intolerance (IEI). METHODS: The study included participants who had previously participated in a general population-based study and reported symptoms of environmental intolerance (n = 787) and patients with IEI (n = 237). The participants completed questionnaires assessing IEI, namely, a measure of repressive coping combining scores on the Marlowe-Crowne Social Desirability Scale (MCSDS) and the Taylor Manifest Anxiety Scale (TMAS), the Toronto Alexithymia Scale (TAS-20), and a negative affectivity scale (NAS). Multiple, hierarchical linear regression analyses were conducted using IEI variables as the dependent variables. RESULTS: The TMAS and MCSDS scores were independently associated with the IEI variables, but there was no evidence of a role of the repressive coping construct. While the total alexithymia score was unrelated to IEI, the TAS-20 subscale of difficulties identifying feelings (DIF) was independently associated with symptoms attributed to IEI. Negative affectivity was a strong independent predictor of the IEI variables and a mediator of the association between DIF and IEI. CONCLUSION: Our results provide no evidence for a role of repressive coping in IEI, and our hypothesis of an association with alexithymia was only partly supported. In contrast, strong associations between IEI and negative emotional reactions, defensiveness and difficulties identifying feelings were found, suggesting a need for exploring the influence of these emotional reactions in IEI.

Attention to bodily sensations and symptom perception in individuals with idiopathic environmental intolerance.

INTRODUCTION: Idiopathic environmental intolerance (IEI) is characterized by non-specific symptoms attributed to exposure to environmental odours or chemicals at levels below those known to induce adverse health effects. A clarification of whether psychological processes involved in sensory perceptions are associated with IEI would add to our understanding of this complex disorder. PURPOSE: To examine if measures of somato-sensory amplification, autonomic perception and absorption are associated with IEI. METHODS: The study included individuals with self-reported or physician-diagnosed IEI. Participants (n = 732) completed questionnaires that included items on descriptive variables of IEI, the Somato-Sensory Amplification Scale (SSAS), the Autonomic Perception Questionnaire (APQ), the Tellegen Absorption Scale (TAS) and a Negative Affectivity Scale (NAS). RESULTS: Multiple, hierarchical linear regression analyses revealed significant positive associations between SSAS, APQ, and IEI, while small and inverse associations were seen between TAS and IEI. CONCLUSIONS: The association with SSAS and APQ suggests that perceptual personality characteristics are important in understanding this disorder.

General practitioners' experiences with provision of healthcare to patients with self-reported multiple chemical sensitivity.

OBJECTIVE: To describe general practitioners' (GPs') evaluation of and management strategies in relation to patients who seek medical advice because of multiple chemical sensitivity (MCS). DESIGN: A nationwide cross-sectional postal questionnaire survey. The survey included a sample of 1000 Danish GPs randomly drawn from the membership list of GPs in the Danish Medical Association. SETTING: Denmark. RESULTS: Completed questionnaires were obtained from 691 GPs (69%). Within the last 12 months 62.4% (n = 431) of the GPs had been consulted by at least one patient with MCS. Of these, 55.2% of the GPs evaluated the patients' complaints as chronic and 46.2% stated that they were rarely able to meet the patients' expectations for healthcare. The majority, 73.5%, had referred patients to other medical specialties. The cause of MCS was perceived as multi-factorial by 64.3% of the GPs, as somatic/biologic by 27.6%, and as psychological by 7.2%. Partial or complete avoidance of chemical exposures was recommended by 86.3%. Clinical guidelines, diagnostic tools, or more insight in the pathophysiology were requested by 84.5% of the GPs. CONCLUSION: Despite the lack of formal diagnostic labelling the patient with MCS is well known by GPs. The majority of the GPs believed that MCS primarily has a multi-factorial explanation. However, perceptions of the course of the condition and management strategies differed, and many GPs found it difficult to meet the patients' expectations for healthcare. The majority of the GPs requested more knowledge and clinical guidelines for the management of this group of patients.

A step towards a new delimitation of functional somatic syndromes: A latent class analysis of symptoms in a population-based cohort study.

OBJECTIVES: The current delimitation of functional somatic syndromes (FSS) is inconsistent. We aimed to investigate somatic symptom profiles in the general adult population to contribute to a new, data-driven delimitation of FSS. METHODS: Information on 31 self-reported somatic symptoms used in the delimitation of various FSS and bodily distress syndrome (BDS) was obtained from the DanFunD study-a population-based cohort study on 9656 adults (participation 33.6%) from Greater Copenhagen, Denmark. Latent class analysis was used to identify symptom profiles. The profiles were described by their relation with sex, age, chronic disease, self-perceived health, symptom impact, self-reported FSS, and BDS case-status. RESULTS: Eight symptom profiles were identified. The largest profile had no symptoms (49% of the population). Three profiles were characterized by a few, specific symptoms: muscle and joint pain (17%), gastrointestinal symptoms (6%), and general symptoms (13%). Three profiles had multiple symptoms in specific combinations: musculoskeletal and general symptoms (7%); fatigue, musculoskeletal and gastrointestinal symptoms (3%); and cardiopulmonary, gastrointestinal and general symptoms (3%). Lastly, one profile (2%) had high probability of all symptoms. The last four profiles (15%) were strongly associated with BDS case-status, poor self-perceived health and high impact of symptoms. Analyses excluding persons with multi-symptomatic chronic disease showed similar results. CONCLUSIONS: We identified eight symptom profiles characterized by specific combinations of symptoms. Four of these had multiple symptoms from several bodily systems showing large overlap with BDS, possibly indicating subtypes of FSS. The profiles contribute to a new delimitation of FSS by illustrating the importance of specific symptom combinations.

Conditioned Pain Modulation and Pressure Pain Sensitivity in the Adult Danish General Population: The DanFunD Study.

Increased pressure pain sensitivity and impaired descending pain control have been associated with chronic pain, but knowledge on the variability in the adult general population is lacking. Pressure pain thresholds (PPTs) and descending pain control assessed using conditioned pain modulation (CPM) were recorded in a randomly selected sample (n = 2,199, 53% female) of the Danish adult general population aged 18 to 70 years. PPTs were recorded over the tibialis anterior muscle and the upper trapezius muscle. CPM was defined as the difference between PPT assessments before and during conditioning with cold pressor pain (hand) for 2 minutes. Conditioning pain intensity was assessed using a visual analog scale and questionnaire data were collected. Female sex (P < .001) and younger age (P ≤ .02) was associated with lower PPTs at both body sites. For the trapezius muscle, high perceived stress was associated with lower PPTs (P < .02), whereas an interaction was found between body mass index and sex. CPM potency was lower in female compared with male participants (P ≤ .003), whereas no association with age was found. Higher level of education (P ≤ .05), premature withdrawal from the cold pressor test (P ≤ .02), and high visual analog scale score (P ≤ .02) were associated with a larger CPM response. PERSPECTIVE: Data from this large population-based study provide new insight into the gender and age variation in pain sensitivity and CPM response. Decreased CPM potency and increased pain sensitivity in female participants were found, emphasizing the need to improve the understanding of its clinical consequences.

Irritable bowel symptoms and the development of common mental disorders and functional somatic syndromes identified in secondary care - a long-term, population-based study.

OBJECTIVE: Irritable bowel syndrome (IBS) is associated with mental vulnerability, and half of patients report comorbid somatic and mental symptoms. We aimed to investigate the relationship between an IBS symptom continuum and the subsequent development of common mental disorders (CMDs) and functional somatic syndromes (FSSs). METHODS AND STUDY DESIGN: A longitudinal population-based study comprising two 5-year follow-up studies, Dan-MONICA 1 (1982-1987) and Inter99 (1999-2004), recruited from the western part of Copenhagen County. The total study population (n = 7,278) was divided into symptom groups according to the degree of IBS definition fulfillment at baseline and/or follow-up and was followed until December 2013 in Danish central registries. Cox regression was used for the analyses, adjusting for age, sex, length of education and cohort membership. In a subsequent analysis, we adjusted for mental vulnerability as a risk factor for both CMDs and FSSs, including IBS. RESULTS: Over a 5-year period, 51% patients had no IBS symptoms, 17% patients had IBS symptoms without abdominal pain, 22% patients had IBS symptoms including abdominal pain and 10% patients fulfilled the IBS definition. IBS and IBS symptoms including abdominal pain were significantly associated with the development of CMDs and other FSSs identified in secondary care. When adjusting for mental vulnerability, IBS and IBS symptoms including abdominal pain were no longer associated with CMDs, but the significant relationship to other FSSs remained. CONCLUSION: In a clinical setting, the perspective should be broadened to individuals not fulfilling the symptom cluster of IBS but who report frequent abdominal pain. Additionally, it is important to combine symptom-based criteria of IBS with psychosocial markers such as mental vulnerability, because it could guide clinicians in decisions regarding prognosis and treatment.

Gene expression profiling in persons with multiple chemical sensitivity before and after a controlled n-butanol exposure session.

OBJECTIVES: To investigate the pathophysiological pathways leading to symptoms elicitation in multiple chemical sensitivity (MCS) by comparing gene expression in MCS participants and healthy controls before and after a chemical exposure optimised to cause symptoms among MCS participants.The first hypothesis was that unexposed and symptom-free MCS participants have similar gene expression patterns to controls and a second hypothesis that MCS participants can be separated from controls based on differential gene expression upon a controlled n-butanol exposure. DESIGN: Participants were exposed to 3.7 ppm n-butanol while seated in a windowed exposure chamber for 60 min. A total of 26 genes involved in biochemical pathways found in the literature have been proposed to play a role in the pathogenesis of MCS and other functional somatic syndromes were selected. Expression levels were compared between MCS and controls before, within 15 min after being exposed to and 4 hours after the exposure. SETTINGS: Participants suffering from MCS and healthy controls were recruited through advertisement at public places and in a local newspaper. PARTICIPANTS: 36 participants who considered themselves sensitive were prescreened for eligibility. 18 sensitive persons fulfilling the criteria for MCS were enrolled together with 18 healthy controls. OUTCOME MEASURES: 17 genes showed sufficient transcriptional level for analysis. Group comparisons were conducted for each gene at the 3 times points and for the computed area under the curve (AUC) expression levels. RESULTS: MCS participants and controls displayed similar gene expression levels both at baseline and after the exposure and the computed AUC values were likewise comparable between the 2 groups. The intragroup variation in expression levels among MCS participants was noticeably greater than the controls. CONCLUSIONS: MCS participants and controls have similar gene expression levels at baseline and it was not possible to separate MCS participants from controls based on gene expression measured after the exposure.

Somatic symptom profiles in the general population: a latent class analysis in a Danish population-based health survey.

PURPOSE: The aim of this study was to identify and describe somatic symptom profiles in the general adult population in order to enable further epidemiological research within multiple somatic symptoms. METHODS: Information on 19 self-reported common somatic symptoms was achieved from a population-based questionnaire survey of 36,163 randomly selected adults in the Capital Region of Denmark (55.4% women). The participants stated whether they had been considerably bothered by each symptom within 14 days prior to answering the questionnaire. We used latent class analysis to identify the somatic symptom profiles. The profiles were further described by their association with age, sex, chronic disease, and self-perceived health. RESULTS: We identified 10 different somatic symptom profiles defined by number, type, and site of the symptoms. The majority of the population (74.0%) had a profile characterized by no considerable bothering symptoms, while a minor group of 3.9% had profiles defined by a high risk of multiple somatic symptoms. The remaining profiles were more likely to be characterized by a few specific symptoms. The profiles could further be described by their associations with age, sex, chronic disease, and self-perceived health. CONCLUSION: The identified somatic symptom profiles could be distinguished by number, type, and site of the symptoms. The profiles have the potential to be used in further epidemiological studies on risk factors and prognosis of somatic symptoms but should be confirmed in other population-based studies with specific focus on symptom burden.