Assessment of functional somatic disorders in epidemiological research: Self-report questionnaires versus diagnostic interviews

Factors associated with having previously received a diagnosis of fibromyalgia, chronic fatigue syndrome and irritable bowel syndrome: A cross sectional DanFunD study

OBJECTIVES

Fibromyalgia, chronic fatigue syndrome, and irritable bowel syndrome are highly prevalent conditions and part of the functional somatic syndromes (FSS) diagnosis, that are classified under the unifying umbrella term functional somatic disorder (FSD). Multiple factors are associated with FSD symptom development; However, few studies have explored these associations in relation to the diagnosis status. This study aims to examine associations with a previously received FSS diagnosis from a physician in participants fulfilling the FSD diagnostic criteria in a population-based sample.

METHODS

This research employs a comprehensive observational approach using a cross sectional design with data from the DanFunD part two cohort. Information about received FSS diagnoses was obtained from self-reported questionnaires. Participants fulfilling the FSD diagnostic criteria were identified with both self-reported questionnaires and diagnostic interviews. Validated questionnaires were used to assess the examined factors.

RESULTS

1704 cases fulfilled the diagnostic criteria for an FSD according to questionnaires or interviews in the DanFunD study. In participants fulfilling the diagnostic criteria, having previously received an FSS diagnosis by a physician was strongly associated with female sex, negative illness perceptions and poor health-related quality of life for questionnaire and interview-based diagnoses. Less consistent associations were observed for lower socioeconomic status, anxiety, and adverse life events.

CONCLUSION

Previously received FSS diagnoses showed associations with multiple factors with a particular strong association with female sex and poor health related quality of life.

Physiological correlates of anxiety in childhood and adolescence: A systematic review and meta-analysis

Anxiety is one of the most prevalent problems that affects children and adolescents. The vast majority of diagnostic tools for anxiety depend on written or verbal reports from children and adolescents or their significant others. The validity and reliability of such reports can be compromised by their subjective nature. Thus, there is growing interest in whether anxiety can be indexed with objective physiological measures. The key aim of this systematic review and meta-analysis was to determine which physiological measures are most reliably associated with elevated levels of anxiety amongst children and adolescents. Online databases (e.g., PsycINFO, Embase, Medline) were searched for relevant studies according to pre-determined criteria. Twenty-five studies comprising 2502 participants (N = 1160 with high anxiety) met inclusion, identifying 11 groups of physiological measures. Our meta-analysis revealed that skin conductance level is the most sensitive measure of anxiety (d = 0.83), followed by electromyography (EMG) measures (d = 0.71) and skin conductance response (d = 0.58). However, the included studies varied in terms of subjective measures, study designs, experimental task measures, and physiological measures. Consideration of these differences in methodology offer potential directions for future research.

Is reduced heart rate variability associated with functional somatic disorders? A cross-sectional population-based study; DanFunD

OBJECTIVES

It has been hypothesised that functional somatic disorders (FSD) could be initiated by sympathetic predominance in the autonomic nervous system as measured by low heart rate variability (HRV). Earlier studies on the association between HRV and FSD are small case-control studies hampered by selection bias and do not consider the great overlap between the various FSDs. The aim of the present study is to assess any associations between HRV and various FSDs and whether chronic stress confounds such an association.

DESIGN

A cross-sectional general population-based study.

SETTING

The Danish Study of Functional Somatic Disorders conducted 2013-2015 in 10 municipalities in the western part of Greater Copenhagen, Denmark.

PARTICIPANTS

A total of 6891 men and women aged 18-72 years were included in the analyses after exclusion of 602 persons with missing HRV data. Various delimitations of FSD (chronic fatigue, chronic widespread pain, irritable bowel and bodily distress syndrome) were identified by validated questionnaires and diagnostic interviews. HRV parameters in time and frequency domains were calculated from successive beat-to-beat heart rate (HR) data using the 'E-motion' HR monitor device during 7 min of supine rest. Chronic stress was assessed by Cohen's self-perceived stress scale.

OUTCOME MEASURES

Logistic regression analyses were used to calculate possible associations between the various delimitations of FSD and HRV adjusting for chronic stress.

RESULTS

Persons with FSD had a slightly higher mean HR and lower HRV as measured by time domain parameters, whereas associations with frequency domain parameters were not consistent. Adjusting for chronic stress attenuated associations slightly.

CONCLUSION

The study supports a sympathetic predominance in persons with FSD, which could not be entirely explained by chronic stress. However, it is not possible to conclude whether the association is a causal factor to or a consequence of FSD.

The association between trichotillomania symptoms and emotion regulation difficulties: A systematic review and meta-analysis

BACKGROUND

Emotion regulation is postulated to play an important role in Trichotillomania (TTM). Whilst a growing number of studies have examined the relationship between emotion regulation difficulties and TTM symptoms, there have been no attempts to evaluate the overall strength of this association or the quality of the evidence base.

METHOD

This systematic review and meta-analysis aimed to synthesise findings from studies that have examined the relationship between emotion regulation difficulties and TTM symptoms, to inform future TTM treatment targets. We identified 17 studies that met inclusion criteria. From these studies, 32 correlation coefficients were extracted for meta-analysis. The Joanna Briggs Institute Checklist for Analytical Cross Sectional Studies was used to assess risk of bias amongst the included studies.

RESULTS

There was a moderately sized association between TTM symptoms and ER difficulties, (r adjusted = 0.32, 95 % CI [0.28, 0.37], t = 15.58 (df = 11.86), p < 0.0001) that was moderated by sample size (F(df1 = 1, df2 = 30) = 4.597, b = -0.0001, SE = 0.0001, 95 % CI [-0.0002; 0.0000], p = 0.040) and differences between types of emotion regulation measures (Q(df = 1) = 4.06, p = 0.044).

LIMITATIONS

The data analysed was correlational, therefore causality was unable to be determined. Comorbidities were not able to be examined as a moderator.

CONCLUSION

This study provided a preliminary integration of the evidence and demonstrated that individuals with higher levels of TTM severity appear to exhibit decreased overall emotion regulation abilities and strategies.

Are Sexual Assaults Related to Functional Somatic Disorders? A Cross-Sectional Study

An increasing number of sexual assaults (SAs) are being reported. This study investigated associations between SA and FSD, conceptualized as bodily distress syndrome (BDS), and five functional somatic syndromes (FSSs): chronic widespread pain (CWP), irritable bowel (IB), chronic fatigue (CF), multiple chemical sensitivity (MCS), and whiplash-associated disorder (WAD). Participants (n = 7493) from the population-based cohort Danish Study of Functional Disorders (DanFunD) completed questionnaires on FSD, emotional distress, SA, and sociodemographics. Risk ratios (RRs) for each FSD and emotional distress were calculated in nine models with SA as the primary exposure using generalized linear models with binomial family and log link and were adjusted for other potential risk factors. The results showed that SA was associated with single-organ FSD (RR = 1.51; 95% CI = 1.22-1.87), multi-organ FSD (RR = 3.51; 95% CI = 1.89-6.49), CWP (RR = 1.28; 95% CI = 0.83-1.98), IB (RR = 2.00; 95% CI = 1.30-3.07), CF (RR = 1.81; 95% CI = 1.42-2.32), WAD (RR = 2.62; 95% CI = 1.37-5.03), MCS (RR = 3.04; 95% CI = 1.79-5.17), emotional distress (RR = 1.75; 95% CI = 1.21-2.54), and health anxiety (RR = 1.65; 95% CI = 1.10-2.46). Overall, SA victims experienced significantly more somatic symptoms than individuals not exposed to SA. Adjusting for physical and emotional abuse did not change the observed associations. Our results suggest a large impact of SA on the overall somatic and mental health of SA victims. Due to the cross-sectional study design, further studies are required.

Ionic liquids revolutionizing biomedicine: recent advances and emerging opportunities

Ionic liquids (ILs), due to their inherent structural tunability, outstanding miscibility behavior, and excellent electrochemical properties, have attracted significant research attention in the biomedical field. As the application of ILs in biomedicine is a rapidly emerging field, there is still a need for systematic analyses and summaries to further advance their development. This review presents a comprehensive survey on the utilization of ILs in the biomedical field. It specifically emphasizes the diverse structures and properties of ILs with their relevance in various biomedical applications. Subsequently, we summarize the mechanisms of ILs as potential drug candidates, exploring their effects on various organisms ranging from cell membranes to organelles, proteins, and nucleic acids. Furthermore, the application of ILs as extractants and catalysts in pharmaceutical engineering is introduced. In addition, we thoroughly review and analyze the applications of ILs in disease diagnosis and delivery systems. By offering an extensive analysis of recent research, our objective is to inspire new ideas and pathways for the design of innovative biomedical technologies based on ILs.

Functional Somatic Disorders, Their Subtypes, and Their Association With Self-Rated Health in the German General Population

OBJECTIVE

The heterogeneous conceptualizations and classifications of persistent and troublesome physical symptoms impede their adequate clinical management. Functional somatic disorder (FSD) is a recently suggested interface concept that is etiologically neutral and allows for dysfunctional psychobehavioral characteristics as well as somatic comorbidity. However, its prevalence and impact are not yet known.

METHODS

We analyzed 2379 participants (mean age = 48.3 years, 52.5% female) from a representative German community survey using operationalized FSD criteria. These criteria defined FSD types based on somatic symptom count, type, and severity assessed by the Bodily Distress Syndrome Checklist. In addition, the associations of those types with health concerns, comorbidity, psychological distress, and self-rated health were determined.

RESULTS

There were four clearly demarcated groups with no relevant bothering symptoms, with one or with few bothering symptoms from one organ system, and with multiple bothering symptoms from at least two organ systems. Psychological distress, health concerns, and comorbidity steadily increased, and self-rated health decreased according to the number and severity of symptoms. Somatic symptom burden, health concerns, and comorbidity independently predicted self-rated health, with no interaction effect between the latter two.

CONCLUSIONS

Our data support an FSD concept with two severity grades according to persistent and troublesome symptoms in one versus more organ systems. The delimitation of subtypes with psychobehavioral characteristics and/or with somatic comorbidity seems useful, while still allowing the demarcation of a group of participants with high symptom burden but without those additional characteristics.

Coping strategies among individuals with multiple physical symptoms: A general population-based cross-sectional study

OBJECTIVE

Coping has been suggested as a perpetuating factor for physical symptoms. The aim of this study was to examine the use of the coping strategies approach, resignation, and diversion in individuals with multiple physical symptoms according to the construct of Bodily Distress Syndrome (BDS).

METHODS

This cross-sectional study was part of the nationwide web-based survey Danish Symptom Cohort (DaSC). In total, 100,000 individuals were invited to participate, and individuals eligible for the present study were respondents aged 20-64 years without a current or recent pregnancy. Multiple physical symptoms were identified using the BDS checklist, and coping was assessed by the Brief Approach/Avoidance Coping Questionnaire. Statistical analyses included descriptive statistics and multinomial and logistic regression.

RESULTS

A total of 35,810 respondents were included in the study, of which 8512 (23.8%) fulfilled the criteria for having multiple physical symptoms. This group of respondents had lower coping scores on approach and higher coping scores on resignation and diversion compared with the non-BDS group. The regression analyses showed that high scores on approach were associated with a lower probability of having multiple symptoms (adjusted OR 0.92, 95% CI: 0.91-0.92), whereas high scores on diversion and resignation were associated with a higher probability of having multiple symptoms (adjusted OR 1.10; 95% CI: 1.09-1.11 and adjusted OR 1.19; 95% CI: 1.18-1.20, respectively).

CONCLUSION

The study supports the hypothesis that experiencing multiple physical symptoms is associated with certain coping strategies. This is relevant knowledge for health care professionals who will be treating this patient group.

Association between infections and functional somatic disorders: a cross-sectional population-based cohort study

OBJECTIVES

It has been suggested that infections can trigger functional somatic disorders (FSD). However, current evidence is limited by inconsistent findings in smaller studies conducted in clinical settings within selected populations and short follow-up times. We aimed to test the hypothesis that former infections are associated with FSD using data from nationwide registries and a large population-based cohort study, the Danish Study of Functional Disorders study.

DESIGN

FSD cases were identified in a cross-sectional population-based cohort and linked retrospectively to former hospital contacts with infections identified in the Danish National Patient Registry. The associations between FSD and former infections within 17 years were analysed using logistic regressions to calculate ORs and 95% CIs adjusted for age, sex and subjective social status.

SETTING

A population-based cohort in Denmark examined between 2011 and 2015.

PARTICIPANTS

A total of 9656 men and women aged 18-76 years.

MAIN OUTCOME MEASURES

FSD measured by various delimitations, including bodily distress syndrome (BDS), irritable bowel (IB), chronic fatigue (CF), chronic widespread pain (CWP), and multiple chemical sensitivity (MCS).

RESULTS

Overall, infections were associated with increased risk of all delimitations of FSD. The associations were more pronounced for multisystemic FSD. The number of prior infections increased the risk in a dose-response manner (p<0.0001). Bacterial but not viral infections were significantly associated with BDS (OR 1.69 (95% CI 1.46 to 1.96)), IB (OR 1.41 (95% CI 1.06 to 1.88)), CWP (OR 1.47 (95% CI 1.13 to 1.90)) and CF (OR 1.62 (95% CI 1.34 to 1.96)), but not MCS.

CONCLUSION

Former infections leading to hospital contacts were associated with a higher risk of having FSD. These associations were more pronounced for bacterial than viral infections, and more infections increased the risk in a dose-response manner. These results tend to support the idea that severe infections could play a role in FSD.

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.

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.

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 (OR^{PPT trapezius}: 0.66, 95% CI: 0.49–0.88, p = .005), with the symptom profile characterized by all symptoms (OR^{PPT trapezius}: 0.72, 95% CI: 0.58–0.90, p = .003 and OR^{PPT tibialis}: 0.75, 95% CI: 0.62–0.91, p = .004), and with multiple chemical sensitivity (OR^{PPT trapezius}: 0.81, 95% CI: 0.67–0.97, p = .022). High CPM was associated with high odds of having irritable bowel (OR^{CPM relative}: 1.22, 95% CI: 1.04–1.43, p = .013 and OR^{CPM 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.