Risk markers for both chronic fatigue and irritable bowel syndromes: a prospective case-control study in primary care

Prevalence of Fibromyalgia and Chronic Fatigue Syndrome among Individuals with Irritable Bowel Syndrome: An Analysis of United States National Inpatient Sample Database

Background and Aim: Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder associated with other somatic disorders. We studied the prevalence and predictors of fibromyalgia and chronic fatigue syndrome (CFS) in IBS patients. Methods: We used the National Inpatient Sample and included hospitalization of individuals with IBS, using ICD-10 codes, from 2016-2019. The prevalence and predictors of fibromyalgia and CFS in IBS patients were studied. Univariate and multivariate patient- and hospital-level regression models were used to calculate the adjusted odds of fibromyalgia and CFS in the IBS patient population. Results: Of 1,256,325 patients with an ICD-10 code of IBS included in the study, 10.73% (134,890) also had ICD-10 codes for fibromyalgia and 0.42% (5220) for CFS. The prevalence of fibromyalgia and CFS was significantly higher in IBS patients (adjusted odds ratio (AOR) 5.33, 95% confidence interval (CI) 5.24-5.41, p < 0.001, and AOR 5.40, 95% CI 5.04-5.78, p < 0.001, respectively) compared to the general adult population without IBS. IBS-diarrhea, IBS-constipation, and IBS-mixed types were independently associated with increased odds of fibromyalgia and CFS. Increasing age (AOR 1.02, 95% CI 1.01-1.04, p 0.003; AOR 1.02, 95% CI 1.01-1.03, p 0.001), female gender (AOR 11.2, 95% CI 11.1-11.4, p < 0.001; AOR 1.86, 95% CI 1.78-1.93, p < 0.001) and white race (AOR 2.04, 95% CI 1.95-2.12, p < 0.001; AOR 1.69, 95% CI 1.34-2.13, p < 0.001) were independent predictors of increased odds of fibromyalgia and CFS, respectively. Conclusions: It appears that IBS is associated with an increased prevalence of somatic disorders such as fibromyalgia and CFS.

Aetiological Understanding of Fibromyalgia, Irritable Bowel Syndrome, Chronic Fatigue Syndrome and Classificatory Analogues: A Systematic Umbrella Review

Background

This umbrella review systematically assesses the variety and relative dominance of current aetiological views within the scientific literature for the three most investigated symptom-defined functional somatic syndromes (FSS) and their classificatory analogues within psychiatry and psychology.

Method

An umbrella review of narrative and systematic reviews with and without meta-analyses based on a search of electronic databases (PubMed, Web of Science, Embase, PsychINFO) was conducted. Eligible reviews were published in English, focused on research of any kind of aetiological factors in adults diagnosed with fibromyalgia syndrome (FMS), irritable bowel syndrome (IBS), chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME), and somatic symptom disorder (SSD)/somatoform disorder (SFD).

Results

We included 452 reviews (132 systematic reviews including meta-analyses, 133 systematic reviews, 197 narrative reviews), of which 132 (29%) focused on two or more of the investigated health conditions simultaneously. Across diagnoses, biological factors were addressed in 90% (k = 405), psychological in 33% (k = 150), social in 12% (k = 54), and healthcare factors in 5% (k = 23) of the reviews. The methodological quality of the included systematic reviews (k = 255) was low (low/critically low: 41% [k = 104]; moderate: 49% [k = 126]; high quality: 10% [k = 25]). The high-quality systematic reviews suggest that deficient conditioned pain modulation, genetic factors, changes in the immune, endocrinological, gastrointestinal, cardiovascular, and nervous system, and psychosocial factors such as sexual abuse and pain catastrophizing increase the risk for FSS.

Conclusion

Only very few systematic reviews have used comprehensive, biopsychosocial disease models to guide the selection of aetiological factors in FSS research. Future research should strive for higher scientific standards and broaden its perspective on these health conditions.

Psychiatric disorders and the onset of self-reported fibromyalgia and chronic fatigue syndrome: The lifelines cohort study

Introduction

This study aimed to assess whether psychiatric disorders predict the onset of fibromyalgia and chronic fatigue syndrome (CFS) which develop in the presence of pre-existing muscle pain or fatigue.

Methods

The population-based Lifelines cohort study included 148,614 adults with relevant data for the fibromyalgia study and 136,423 for the CFS study. Participants with prior self-reported fibromyalgia (or CFS) at baseline were excluded from the relevant analysis. At follow-up (mean 2.4 years), new onsets of each syndrome were identified by self-report. Logistic regression was used to identify which of the baseline variables predicted new onsets of each syndrome. The total number of psychiatric disorders (depression, anxiety, burnout, panic disorder, social phobia, agoraphobia, obsessive-compulsive, and eating disorders) was used as a predictor. Prior to the analyses the samples were divided into those with and without marked muscle pain (for fibromyalgia analysis) or persistent fatigue (for CFS).

Results

During follow-up, there were 685/136,423 (0.5%) new onsets of self-reported FM in participants without marked muscle pain and 281/7481 (3.75%) in those with such pain; for CFS it was 292/124,223 (0.2%) for those without and 192/10,025 (1.9%) for those with baseline fatigue. In both univariate and logistic regression analyses of participants with prior persistent fatigue psychiatric disorder was clearly associated with onset of CFS. This was not so for onset of fibromyalgia in participants with prior muscle pain.

Discussion

Although psychiatric disorders did not predict self-reported fibromyalgia or CFS in participants free of pain or fatigue at baseline, in this study psychiatric disorder did predict self-reported CFS in the presence of pre-existing fatigue. Progress in understanding the etiology of these disorders may require studying separately onsets with and without pre-existing key symptoms.

Predictors of new onsets of irritable bowel syndrome, chronic fatigue syndrome and fibromyalgia: the lifelines study

BACKGROUND

It has been claimed that functional somatic syndromes share a common etiology. This prospective population-based study assessed whether the same variables predict new onsets of irritable bowel syndrome (IBS), chronic fatigue syndrome (CFS) and fibromyalgia (FM).

METHODS

The study included 152 180 adults in the Dutch Lifelines study who reported the presence/absence of relevant syndromes at baseline and follow-up. They were screened at baseline for physical and psychological disorders, socio-demographic, psycho-social and behavioral variables. At follow-up (mean 2.4 years) new onsets of each syndrome were identified by self-report. We performed separate analyses for the three syndromes including participants free of the relevant syndrome or its key symptom at baseline. LASSO logistic regressions were applied to identify which of the 102 baseline variables predicted new onsets of each syndrome.

RESULTS

There were 1595 (1.2%), 296 (0.2%) and 692 (0.5%) new onsets of IBS, CFS, and FM, respectively. LASSO logistic regression selected 26, 7 and 19 predictors for IBS, CFS and FM, respectively. Four predictors were shared by all three syndromes, four predicted IBS and FM and two predicted IBS and CFS but 28 predictors were specific to a single syndrome. CFS was more distinct from IBS and FM, which predicted each other.

CONCLUSIONS

Syndrome-specific predictors were more common than shared ones and these predictors might form a better starting point to unravel the heterogeneous etiologies of these syndromes than the current approach based on symptom patterns. The close relationship between IBS and FM is striking and requires further research.

Mast Cell Activation Syndrome: A Primer for the Gastroenterologist

Mast cell activation syndrome is thought to be a common, yet under-recognized, chronic multi-system disorder caused by inappropriate mast cell activation. Gastrointestinal symptoms are frequently reported by these patients and are often mistaken by physicians as functional gastrointestinal disorders. This syndrome can be diagnosed by the medical history and measurable biomarkers. Gastroenterologists manage diseases associated with active inflammatory cells including neutrophils, lymphocytes, macrophages, and eosinophils. The mast cell has only recently been recognized as a major player in our specialty. Gastrointestinal disorders from mast cell mediators often present with apparent irritable bowel syndrome, dyspepsia, chronic or cyclical nausea, and heartburn. Individuals with mast cell activation syndrome experience significant delays in diagnosis. The gastrointestinal symptoms are often refractory to symptom-targeted prescription medications. Beyond avoiding triggers, the best therapy is directed at modulating mast cell activation and the effects of the mediators. Many of these therapies are simple over-the-counter medications. In this article, we review mast cell function and dysfunction and the gastrointestinal symptoms, comorbid conditions, diagnosis, and management of mast cell activation syndrome. Gastroenterologists who become aware of this syndrome can dramatically improve the quality of life for their patients who previously have been labeled with a functional gastrointestinal disorder.

Functional gastrointestinal disorders: advances in understanding and management

Gastrointestinal symptoms are highly prevalent, but many people who have them will have no organic explanation for their symptoms. Most of these people will be labelled as having a functional gastrointestinal disorder, such as irritable bowel syndrome, functional dyspepsia, or functional constipation. These conditions affect up to 40% of people at any one point in time, and two-thirds of these people will have chronic, fluctuating symptoms. The pathophysiology of functional gastrointestinal disorders is complex, but involves bidirectional dysregulation of gut-brain interaction (via the gut-brain axis), as well as microbial dysbiosis within the gut, altered mucosal immune function, visceral hypersensitivity, and abnormal gastrointestinal motility. Hence, nomenclature refers to the conditions as disorders of gut-brain interaction. Psychological comorbidity is common; however, whether or not this predates, or is driven by, symptoms is not clear. Patients with functional gastrointestinal disorders can feel stigmatised, and often this diagnosis is not communicated effectively by physicians, nor is education provided. Prompt identification and treatment of these conditions is crucial as they have a considerable impact on health-care systems and society as a whole because of repeated consultations, unnecessary investigations and surgeries, prescriptions and over-the-counter medicine use, and impaired health-related quality of life and ability to work. Symptom-based criteria are used to make a diagnosis, with judicious use of limited investigations in some patients. The general principles of treatment are based on a biopsychosocial understanding and involve management of physical symptoms and, if present, psychological comorbidity. In the future, treatment approaches to functional gastrointestinal disorders are likely to become more personalised, based not only on symptoms but also underlying pathophysiology and psychology.

Comorbidities of Patients with Functional Somatic Syndromes Before, During and After First Diagnosis: A Population-based Study using Bavarian Routine Data

Functional somatic syndromes (FSS) are characterised by the presence of one or multiple chronic symptoms that cannot be attributed to a known somatic disease. They are thought to arise though a complex interaction of biological and psychosocial factors, but it is unclear whether they share a common aetiology. One hypothesis supported by recent studies is that the FSS are postinfectious disorders, as is widely recognised for a subset of patients with irritable bowel syndrome. Our study used claims data submitted by office-based physicians to compare groups of patients with different FSS in the five years before and after the point of first diagnosis. Even five years prior to diagnosis, FSS patients consulted more frequently for a range of psychological and somatic conditions than did controls. Following diagnosis, consultation rates increased further and remained persistently high. Five years after diagnosis, between 34% (somatization disorder) and 66% (fibromyalgia) of patients were still being treated for the condition. Both prior gastrointestinal and upper-respiratory infection were associated with an increased risk of developing an FSS. We therefore recommend that patients at risk should be identified at an early stage and the underlying psychosocial and somatic issues addressed to prevent progression of the condition.

Review article: the incidence and risk factors for irritable bowel syndrome in population-based studies

BACKGROUND

In the absence of prior gastrointestinal infection, the risk factors for irritable bowel syndrome (IBS) are not well established.

AIM

To identify the incidence and risk factors for IBS in general population samples METHODS: Narrative review of population-based studies. Electronic databases were searched using the keywords "incidence," "onset," "epidemiology," "population," "risk factors" with "irritable bowel syndrome" with subsequent hand searching. Inclusion criteria were: population-based, adults, prospective design (including retrospective case cohorts), clinical or research diagnosis of IBS and exclusion of individuals who had IBS prior to recruitment.

RESULTS

Of 1963 papers, 38 were included; all provided data on risk factors, 27 reported incidence. The median incidence of physician-diagnosed IBS in 19 general population cohorts was 38.5 per 10 000 person-years (interquartile range = 20-45.3). In 14 cohorts with specific medical disorders, median incidence was 92 per 10 000 person-years (IQR: 73.9-119). Apart from gastroenteritis, the most common risk factors were other medical disorders, female sex, age (both young and old), anxiety and depression, life events/stress, frequent healthcare use, pain and sleep disorders. The results were conflicting for alcohol consumption, smoking and BMI. Incidence rates were similar in different countries but risk factors differed.

CONCLUSIONS

Incidence rates were generally lower than previous estimates reflecting physician-diagnosed IBS. The results highlight the importance of other medical and psychosocial problems in the onset of IBS in addition to prior gastrointestinal infections. Aetiological research could be enhanced by studying the underlying mechanisms relating to all of these risk factors.

The associated features of multiple somatic symptom complexes

OBJECTIVE

To assess whether two or more functional somatic symptom complexes (SSCs) showed stronger association with psychosocial correlates than single or no SSC after adjustment for depression/anxiety and general medical disorders.

METHODS

In a population-based sample we identified, by standardised questionnaire, participants with chronic widespread pain, chronic fatigue and irritable bowel syndrome, excluding those with a medical cause for pain/fatigue. We compared psychosocial variables in three groups: multiple (>1), single or no FSS, adjusting for depression/anxiety and general medical disorders using ordinal logistic regression. We evaluated whether multiple SSCs predicted health status 1 year later using multiple regression to adjust for confounders.

RESULTS

Of 1443 participants (58.0% response) medical records were examined in 990: 4.4% (n = 44) had 2 or 3 symptom complexes, 16.2% a single symptom complex. Many psychosocial adversities were significantly associated with number of SSCs in the expected direction but, for many, statistical significance was lost after adjustment for depression/anxiety and medical illness. Somatic symptoms, health anxiety, impairment and number of prior doctor visits remained significantly associated. Impaired health status 1 year later was predicted by multiple somatic symptom complexes even after adjustment for depression, anxiety, medical disorders and number of symptoms.

CONCLUSIONS

Depression, anxiety, medical illness and health anxiety, demonstrated an exposure-response relationship with number of somatic symptom complexes. These may be core features of all Functional Somatic Syndromes and may explain why number of somatic symptom complexes predicted subsequent health status. These features merit inclusion in prospective studies to ascertain causal relationships.

Characteristics of undiagnosed diseases network applicants: implications for referring providers

BACKGROUND

The majority of undiagnosed diseases manifest with objective findings that warrant further investigation. The Undiagnosed Diseases Network (UDN) receives applications from patients whose symptoms and signs have been intractable to diagnosis; however, many UDN applicants are affected primarily by subjective symptoms such as pain and fatigue. We sought to characterize presenting symptoms, referral sources, and demographic factors of applicants to the UDN to identify factors that may determine application outcome and potentially differentiate between those with undiagnosed diseases (with more objective findings) and those who are less likely to have an undiagnosed disease (more subjective symptoms).

METHODS

We used a systematic retrospective review of 151 consecutive Not Accepted and 50 randomly selected Accepted UDN applications. The primary outcome was whether an applicant was Accepted, or Not Accepted, and, if accepted, whether or not a diagnosis was made. Objective and subjective symptoms and information on prior specialty consultations were collected from provider referral letters. Demographic data and decision data on network acceptance were gathered from the UDN online portal.

RESULTS

Fewer objective findings and more subjective symptoms were found in the Not Accepted applications. Not Accepted referrals also were from older individuals, reported a shorter period of illness, and were referred to the UDN by their primary care physicians. All of these differences reached statistical significance in comparison with Accepted applications. The frequency of subspecialty consults for diagnostic purposes prior to UDN application was similar in both groups.

CONCLUSIONS

The preponderance of subjective and lack of objective findings in the Not Accepted applications distinguish these from applicants that are accepted for evaluation and diagnostic efforts through the UDN. Not Accepted applicants are referred primarily by their primary care providers after multiple specialist consultations fail to yield answers. Distinguishing between patients with undiagnosed diseases with objective findings and those with primarily subjective findings can delineate patients who would benefit from further diagnostic processes from those who may have functional disorders and need alternative pathways for management of their symptoms.

TRIAL REGISTRATION

clinicaltrials.gov NCT02450851 , posted May 21st 2015.

Prevalence of Irritable Bowel Syndrome and Chronic Fatigue 10 Years After Giardia Infection

BACKGROUND & AIMS

Irritable bowel syndrome (IBS) is a complication that can follow gastrointestinal infection, but it is not clear if patients also develop chronic fatigue. We investigated the prevalence and odds ratio of IBS and chronic fatigue 10 years after an outbreak of Giardia lamblia, compared with a control cohort, and changes in prevalence over time.

METHODS

We performed a prospective follow-up study of 1252 laboratory-confirmed cases of giardiasis (exposed), which developed in Bergen, Norway in 2004. Statistics Norway provided us with information from 2504 unexposed individuals from Bergen, matched by age and sex (controls). Questionnaires were mailed to participants 3, 6, and 10 years after the outbreak. Results from the 3- and 6-year follow-up analyses have been published previously. We report the 10-year data and changes in prevalence among time points, determined by logistic regression using generalized estimating equations.

RESULTS

The prevalence of IBS 10 years after the outbreak was 43% (n = 248) among 576 exposed individuals and 14% (n = 94) among 685 controls (adjusted odds ratio for development of IBS in exposed individuals, 4.74; 95% CI, 3.61-6.23). At this time point, the prevalence of chronic fatigue was 26% (n = 153) among 587 exposed individuals and 11% (n = 73) among 692 controls (adjusted odds ratio, 3.01; 95% CI, 2.22-4.08). The prevalence of IBS among exposed persons did not change significantly from 6 years after infection (40%) to 10 years after infection (43%; adjusted odds ratio for the change 1.03; 95% CI, 0.87-1.22). However, the prevalence of chronic fatigue decreased from 31% at 6 years after infection to 26% at 10 years after infection (adjusted odds ratio for the change 0.74; 95% CI, 0.61-0.90).

CONCLUSION

The prevalence of IBS did not change significantly from 6 years after an outbreak of Giardia lamblia infection in Norway to 10 years after. However, the prevalence of chronic fatigue decreased significantly from 6 to 10 years afterward. IBS and chronic fatigue were still associated with giardiasis 10 years after the outbreak.

Incidence of irritable bowel syndrome and chronic fatigue following GI infection: a population-level study using routinely collected claims data

OBJECTIVES

To investigate the occurrence of postinfectious IBS in routine outpatient care, comparing different types of GI infection and its interaction with psychosomatic comorbidity.

DESIGN

Retrospective cohort study using routinely collected claims data covering statutorily insured patients in Bavaria, Germany. Cases were defined as patients without prior record of functional intestinal disorder with a first-time diagnosis of GI infection between January 2005 and December 2013 and classed according to the type of infection. Each case was matched by age, sex and district of residence to a patient without history of GI infection. Prior psychological disorder (depression, anxiety or stress reaction disorder) was assessed in the 2 years prior to inclusion. Proportional hazards regression models were used to estimate the HRs for GI infection and psychological disorder. Chronic fatigue syndrome (CFS) was assessed as a comparator outcome.

RESULTS

A total of 508 278 patients with first diagnosis of GI infection were identified, resulting in a matched cohort of 1 016 556 patients. All infection types were associated with an increased risk of IBS (HR: 2.19-4.25) and CFS (HR 1.35-1.82). Prior psychological disorder was a distinct risk factor for IBS (HR: 1.73) and CFS (HR: 2.08). Female sex was a further risk factor for both conditions.

CONCLUSION

Psychological disorder and GI infections are distinct risk factors for IBS. The high incidence of non-specific GI infection suggests that postinfectious IBS is a common clinical occurrence in primary care. Chronic fatigue is a further significant sequela of GI infection.

Infection Elicited Autoimmunity and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: An Explanatory Model

Myalgic encephalomyelitis (ME) often also called chronic fatigue syndrome (ME/CFS) is a common, debilitating, disease of unknown origin. Although a subject of controversy and a considerable scientific literature, we think that a solid understanding of ME/CFS pathogenesis is emerging. In this study, we compiled recent findings and placed them in the context of the clinical picture and natural history of the disease. A pattern emerged, giving rise to an explanatory model. ME/CFS often starts after or during an infection. A logical explanation is that the infection initiates an autoreactive process, which affects several functions, including brain and energy metabolism. According to our model for ME/CFS pathogenesis, patients with a genetic predisposition and dysbiosis experience a gradual development of B cell clones prone to autoreactivity. Under normal circumstances these B cell offsprings would have led to tolerance. Subsequent exogenous microbial exposition (triggering) can lead to comorbidities such as fibromyalgia, thyroid disorder, and orthostatic hypotension. A decisive infectious trigger may then lead to immunization against autoantigens involved in aerobic energy production and/or hormone receptors and ion channel proteins, producing postexertional malaise and ME/CFS, affecting both muscle and brain. In principle, cloning and sequencing of immunoglobulin variable domains could reveal the evolution of pathogenic clones. Although evidence consistent with the model accumulated in recent years, there are several missing links in it. Hopefully, the hypothesis generates testable propositions that can augment the understanding of the pathogenesis of ME/CFS.

The role of attachment in medically unexplained symptoms and long-term illness

In this article, we explore the role of attachment in the development of medically unexplained symptoms (MUS) and response to physical illness. We review the evidence that attachment insecurity is common in people with different forms of MUS and certain long-term physical conditions. We discuss a possible developmental model for understanding how MUS develop. We conclude with discussion of potential therapies and implications for services.

Giardiasis and Subsequent Irritable Bowel Syndrome: A Longitudinal Cohort Study Using Health Insurance Data

Background

Giardia intestinalis is the most commonly reported human intestinal parasite in the United States. Increased incidence of chronic gastrointestinal complaints has been reported after some giardiasis outbreaks. We examined the relationship between giardiasis diagnosis and irritable bowel syndrome (IBS) diagnosis.

Methods

We used the 2006-2010 MarketScan commercial insurance database. Persons with at least 1 giardiasis diagnosis were individually matched on age group, sex, and enrollment length in months to 5 persons without a giardiasis diagnosis. Persons diagnosed with IBS before the date of study entry were excluded. We calculated crude incidence rates (IRs) and developed Cox proportional hazards models.

Results

The matched cohort included 3935 persons with giardiasis and 19663 persons without giardiasis. One-year incidence of IBS was higher in persons with giardiasis (IR = 37.7/1000 person-years vs 4.4/1000 person-years). The unadjusted hazard ratio was 4.8 (95% confidence interval [CI] = 3.6-6.4), attenuated slightly to 3.9 (95% CI = 2.9-5.4) after adjusting for anxiety, depression, and healthcare utilization.

Conclusions

In a large insurance database, individuals diagnosed with giardiasis were more likely to have a subsequent IBS diagnosis, despite accounting for confounders. Future research on risk factors for IBS among giardiasis patients and the pathophysiology of postinfectious IBS is needed.

A systematic review with meta-analysis of the role of anxiety and depression in irritable bowel syndrome onset

BACKGROUND

It is well established that people with irritable bowel syndrome (IBS) have higher levels of anxiety and depression compared with controls. However, the role of these as risk factors is less clearly established. The aims of this systematic review were to investigate: (1) whether anxiety and/or depression predict IBS onset; (2) the size of the relative risk (RR) of anxiety versus depression in IBS onset. Subgroup analyses explored if methodological factors affected the overall findings.

METHOD

Prospective cohort or case-control studies were included if they: (1) focused on the development of IBS in population-based or gastroenteritis cohorts; (2) explored the effects of anxiety and/or depression at baseline as predictors of IBS onset at a future point. In all, 11 studies were included of which eight recruited participants with a gastrointestinal infection. Meta-analyses were conducted.

RESULTS

The risk of developing IBS was double for anxiety cases at baseline compared with those who were not [RR 2.38, 95% confidence interval (CI) 1.58-3.60]. Similar results were found for depression (RR 2.06, 95% CI 1.44-2.96). Anxiety and depression seemed to play a stronger role in IBS onset in individuals with a gastrointestinal infection although this could be attributed to other differences in methodology, such as use of diagnostic interviews rather than self-report.

CONCLUSIONS

The findings suggest that self-reported anxiety and depression provide a twofold risk for IBS onset. There is less support for the role of anxiety or depressive disorder diagnosed using clinical interview. These findings may have implications for the development of interventions focused on IBS prevention and treatment.

Fatigue in Irritable Bowel Syndrome: A Systematic Review and Meta-analysis of Pooled Frequency and Severity of Fatigue

PURPOSE

Fatigue is the third most common "extraintestinal" complaint of patients with irritable bowel syndrome (IBS), but it is still poorly understood. This study aimed to review characteristics of IBS-associated fatigue and to examine pooled frequency, severity of fatigue, and correlations of related factors with fatigue in IBS via meta-analyses.

METHODS

Publications were searched in eight databases from 1995 to 2014. Random effects meta-analyses were applied with standard error, weighted effect size, and correlation-based measure of effect size.

RESULTS

Twenty-four studies were included in systematic review. Seventeen studies were used for meta-analyses (2 studies were excluded in the frequency of fatigue analysis due to data unavailability). Using "tiredness" to define fatigue, and Fatigue Impact Scale to assess fatigue were the most frequently used across the studies. Gastrointestinal symptoms, psychological distress, and health-related quality of life were the most common correlates with fatigue. The pooled frequency of fatigue was 54.2% [95% confidence interval (38.5, 69.4)]. Metaregression on the frequency of fatigue showed positive and significant relations with tertiary care settings, female sex, and younger age. There was a negatively moderate relationship between the severity of fatigue and health-related quality of life score (correlation-based measure of effect size: -.378).

CONCLUSIONS

Fatigue is prevalent among patients with IBS and commonly co-occurs with other symptoms. This is the first study to fully examine fatigue in IBS, which shed light on the comprehensive management of fatigue in this patient group. Future research is warranted to further explore fatigue-related factors and underlying mechanisms of fatigue in IBS.

Bodily distress syndrome: A new diagnosis for functional disorders in primary care?

Background

Conceptualisation and classification of functional disorders appear highly inconsistent in the health-care system, particularly in primary care. Numerous terms and overlapping diagnostic criteria are prevalent of which many are considered stigmatising by general practitioners and patients. The lack of a clear concept challenges the general practitioner’s decision-making when a diagnosis or a treatment approach must be selected for a patient with a functional disorder. This calls for improvements of the diagnostic categories. Intense debate has risen in connection with the release of the fifth version of the ‘Diagnostic and Statistical Manual of Mental Disorders’ and the current revision of the ‘International Statistical Classification of Diseases and Related Health Problems’. We aim to discuss a new evidence based diagnostic proposal, bodily distress syndrome, which holds the potential to change our current approach to functional disorders in primary care. A special focus will be directed towards the validity and utility criteria recommended for diagnostic categorisation.

Discussion

A growing body of evidence suggests that the numerous diagnoses for functional disorders listed in the current classifications belong to one family of closely related disorders. We name the underlying phenomenon ‘bodily distress’; it manifests as patterns of multiple and disturbing bodily sensations. Bodily distress syndrome is a diagnostic category with specific criteria covering this illness phenomenon. The category has been explored through empirical studies, which in combination provide a sound basis for determining a symptom profile, the diagnostic stability and the boundaries of the condition. However, as bodily distress syndrome embraces only the most common symptom patterns, patients with few but impairing symptoms are not captured. Furthermore, the current lack of treatment options may also influence the acceptance of the proposed diagnosis.

Summary

Bodily distress syndrome is a diagnostic category with notable validity according to empirical studies. Nevertheless, knowledge is sparse on the utility in primary care. Future intervention studies should investigate the translation of bodily distress syndrome into clinical practice. A particular focus should be directed towards the acceptability among general practitioners and patients. Most importantly, it should be investigated whether the new category may provide the basis for better treatment and improved clinical outcome.

Common and unique associated factors for medically unexplained chronic widespread pain and chronic fatigue

OBJECTIVE

Chronic widespread pain and chronic fatigue share common associated factors but these associations may be explained by the presence of concurrent depression and anxiety.

METHODS

We mailed questionnaires to a randomly selected sample of people in the UK to identify participants with chronic widespread pain (ACR 1990 definition) and those with chronic fatigue. The questionnaire assessed sociodemographic factors, health status, healthcare use, childhood factors, adult attachment, and psychological stress including anxiety and depression. To identify persons with unexplained chronic widespread pain or unexplained chronic fatigue; we examined participant's medical records to exclude medical illness that might cause these symptoms.

RESULTS

Of 1443 participants (58.0% response rate) medical records of 990 were examined. 9.4% (N=93) had unexplained chronic widespread pain and 12.6% (N=125) had unexplained chronic fatigue. Marital status, childhood psychological abuse, recent threatening experiences and other somatic symptoms were commonly associated with both widespread pain and fatigue. No common effect was found for few years of education and current medical illnesses (more strongly associated with chronic widespread pain) or recent illness in a close relative, neuroticism, depression and anxiety scores (more strongly associated with chronic fatigue). Putative associated factors with a common effect were associated with unexplained chronic widespread pain or unexplained chronic fatigue only when there was concurrent anxiety and/or depression.

DISCUSSION

This study suggests that the associated factors for chronic widespread pain and chronic fatigue need to be studied in conjunction with concurrent depression/anxiety. Clinicians should be aware of the importance of concurrent anxiety or depression.

The common link between functional somatic syndromes may be central sensitisation

OBJECTIVES

Functional somatic syndromes are common and disabling conditions that all include chronic pain, and which may be related to central nervous system sensitisation. Here, we address the concept of central sensitisation as a physiological basis for the functional somatic syndromes.

METHODS

A narrative review of the current literature on central sensitisation and physiological studies in the functional somatic syndromes.

RESULTS

Central sensitisation may be a common neurophysiological process that is able to explain non-painful as well as painful symptoms in these disorders. Furthermore, central sensitisation may represent an endophenotypic vulnerability to the development of these syndromes that potentially explains why they cluster together.

CONCLUSIONS

Further research is needed to verify these findings, including prospective studies and the standardisation of combined methods of investigation in the study of central sensitisation in functional somatic syndromes. In turn, this may lead to new explanatory mechanisms and treatments being evaluated. Our conclusions add to the debate over the nomenclature of these syndromes but importantly also provide an explanation for our patients.

Irritable bowel syndrome and chronic fatigue 6 years after giardia infection: a controlled prospective cohort study

Giardia infection in a nonendemic setting is associated with an increased risk for irritable bowel syndrome and chronic fatigue 6 years later. These conditions should be considered a differential diagnosis in patients with persisting symptoms after eradication of the parasite.

Background. Functional gastrointestinal disorders and fatigue may follow acute infections. This study aimed to estimate the persistence, prevalence, and risk of irritable bowel syndrome and chronic fatigue 6 years after Giardia infection.

Methods. We performed a controlled prospective study of a cohort of 1252 individuals who had laboratory-confirmed Giardia infection during a waterborne outbreak in 2004. In total, 748 cohort cases (exposed) and 878 matched controls responded to a postal questionnaire 6 years later (in 2010). Responses were compared to data from the same cohort 3 years before (in 2007).

Results. The prevalences of irritable bowel syndrome (39.4%) by Rome III criteria and chronic fatigue (30.8%) in the exposed group 6 years after giardiasis were significantly elevated compared with controls, with adjusted relative risks (RRs) of 3.4 (95% confidence interval [CI], 2.9–3.9) and 2.9 (95% CI, 2.3–3.4), respectively. In the exposed group, the prevalence of irritable bowel syndrome decreased by 6.7% (RR, 0.85 [95% CI, .77–.93]), whereas the prevalence of chronic fatigue decreased by 15.3% from 3 to 6 years after Giardia infection (RR, 0.69 [95% CI, .62–.77]). Giardia exposure was a significant risk factor for persistence of both conditions, and increasing age was a risk factor for persisting chronic fatigue.

Conclusions. Giardia infection in a nonendemic setting is associated with an increased risk for irritable bowel syndrome and chronic fatigue 6 years later. The prevalences of both conditions decrease over time, indicating that this intestinal protozoan parasite may elicit very long-term, but slowly self-limiting, complications.

Fatigue and depression in sick-listed chronic low back pain patients

Objective

The relationship between fatigue and pain has been investigated previously, but little is known about the prevalence of substantial fatigue in patients sick-listed for chronic low back pain (CLBP) and about how fatigue is associated with depression, pain, and long-term disability. The aims of the study were to examine the prevalence of substantial fatigue; associations between fatigue, depression, and pain; and whether fatigue predicted long-term disability.

Methods

Five hundred sixty-nine patients participating in a randomized controlled trial and sick-listed 2–10 months for LBP were included in the study. Cross-sectional analyses were conducted to investigate the prevalence and independent associations between fatigue, depression, pain, and disability, while longitudinal analyses were done to investigate the association between fatigue and long-term disability.

Results

The prevalence of substantial fatigue was 69.7%. Women reported significantly more fatigue than men (t = −3.6, df = 551; P < .001). Those with substantial fatigue had higher pain intensity (t = −3.3, df = 534; P = 0.01), more depressive symptoms (t = −10.9, df = 454; P < 0.001), and more disability (t = −7.6, df = 539; P < 0.001) than those without substantial fatigue. Musculoskeletal pain and depression were independently associated with substantial fatigue. In the longitudinal analyses, fatigue predicted long-term disability at 3, 6, and 12 months' follow-up. After pain and depression were controlled for, fatigue remained a significant predictor of disability at 6 months' follow-up.

Conclusions

The vast majority of the sick-listed CLBP patients reported substantial fatigue. Those with substantial fatigue had more pain and depressive symptoms and a significant risk of reporting more disability at 3, 6, and 12 months. Substantial fatigue is disabling in itself but also involves a risk of developing chronic fatigue syndrome and long-term disability.

In search of risk factors for chronic pain in adolescents: a case-control study of childhood and parental associations

Objectives

This study was designed to investigate whether an individual and parental history of functional pain syndromes (FPS) is found more often in adolescents suffering from chronic pain than in their pain-free peers.

Methods

Our case–control study involved 101 adolescents aged 10–18 years. Cases were 45 patients of the Chronic Pain Clinic at Sydney Children’s Hospital with diverse chronic pain disorders. Controls consisted of 56 adolescent volunteers who did not have chronic pain. Adolescents and their parents filled out questionnaires assessing demographic data as well as known and potential risk factors for chronic pain. A history of FPS was assessed by questionnaire, including restless legs syndrome (RLS). Chi-squared tests and t-tests were used to investigate univariate associations between chronic pain in adolescents and lifetime prevalence of FPS. Logistic regression was used to test multivariate associations, while controlling for possible confounders.

Results

Migraine, non-migraine headaches, recurrent abdominal pain (RAP), and RLS were reported significantly more frequently in cases than controls (P-values of 0.01, <0.001, 0.01, and 0.03, respectively). Parental migraine, RAP, and RLS were also significantly associated with adolescent chronic pain in the multivariate analyses. Individual history of migraine, non-migraine headaches, and RAP, along with parental history of RAP and depression significantly accounted for 36%–49% of variance in chronic pain. Other associations with chronic pain were generally in accordance with previous reports.

Discussion

It may be helpful when assessing a child who has chronic pain or is at risk of chronic pain, to enquire about these associations. Based on the current findings, an individual history of migraine, non-migraine headaches, and RAP, as well as parental migraine, RAP, and RLS are symptoms that are of particular relevance to assess.

The epidemiology of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional condition of the bowel that is diagnosed using clinical criteria. This paper discusses the nature of the diagnostic process for IBS and how this impacts epidemiological measurements. Depending on the diagnostic criteria employed, IBS affects around 11% of the population globally. Around 30% of people who experience the symptoms of IBS will consult physicians for their IBS symptoms. These people do not have significantly different abdominal symptoms to those who do not consult, but they do have greater levels of anxiety and lower quality of life. Internationally, there is a female predominance in the prevalence of IBS. There is 25% less IBS diagnosed in those over 50 years and there is no association with socioeconomic status. IBS aggregates within families and the genetic and sociological factors potentially underlying this are reviewed. Patients diagnosed with IBS are highly likely to have other functional disease and have more surgery than the general population. There is no evidence that IBS is associated with an increased mortality risk. The epidemiological evidence surrounding these aspects of the natural history is discussed.

Infection load as a predisposing factor for somatoform disorders: evidence from a Dutch General Practice Registry

OBJECTIVE

Somatoform disorders (SDs) are characterized by chronic multiple functional somatic (FS) symptoms. It has been suggested that infections may be triggers for FS symptoms to occur, pointing to the immune system as a pathogenic factor in their development. The current study aimed to compare the prevalence of infections (i.e., infection load) in the history of patients with SDs with that of matched controls.

METHODS

Samples (n = 185) were identified in the Psychiatric Case Register Middle Netherlands and the Julius General Practitioners Network. Patients with an SD diagnosis in the Psychiatric Case Register Middle Netherlands were compared with matched persons without somatoform complaints (controls) on their infection load in two periods before the date of the psychiatric diagnosis or a matched date for the controls (i.e., the total period for which data were available and a 3-year period). Infection load was defined as the total number of infections documented in the Julius General Practitioners Network.

RESULTS

Patients with SD had significantly more infections than did controls in both periods (total period: mean [standard error] = 0.87 [0.10] versus 0.51 [0.06], z = -3.08, p = .002; 3-year period: 3.44 [0.47] versus 2.15 [0.50], z = -2.91, p = .004).

CONCLUSIONS

Results show that patients with SD have a higher infection load preceding their diagnosis as compared with matched controls, implicating that infection load may indeed predispose for developing FS symptoms. These findings emphasize the importance of further research on immunological mechanisms in FS symptoms. Limitations of the study are discussed.

The number of existing functional somatic syndromes (FSSs) is an important risk factor for new, different FSSs

OBJECTIVE

The objective of this study is to test the hypothesis that the number of functional somatic syndromes (FSSs) predicts new, additional FSSs.

METHODS

In a recent case-control study of interstitial cystitis/painful bladder syndrome (IC/PBS), we used symptom-based consensus definitions to identify these FSSs: fibromyalgia (FM), chronic fatigue syndrome (CFS), irritable bowel syndrome (IBS), chronic pelvic pain, migraine, sicca syndrome and panic disorder. Those present before the incidence year were called antecedent FSSs; those with onset during the incidence year were called incident FSSs. In each of two groups, 312 IC/PBS cases and 313 controls, rates of incident FSSs were compared among those with 0, 1, 2, or ≥3 antecedent FSSs. Confounding was assessed using logistic regression analyses that included the individual antecedent FSSs, published correlates of these FSSs, and demographic variables.

RESULTS

The incidence of a new FSS increased with the number of antecedent FSSs, as did that of incident FM, CFS and IBS studied separately. These findings were not confounded by other variables. The presence of multiple antecedent FSSs generally had the highest odds ratio for new, different, incident FSSs.

CONCLUSIONS

This study revealed that the number of antecedent FSSs was among the strongest risk factors for other FSSs, especially incident FM, CFS and IBS. This suggests that the FSSs are linked through a polysyndromic phenotype. If each FSS is heterogeneous, to seek a pathogenesis common to all FSSs, individuals with multiple FSSs should be sought; to seek a pathogenesis unique to a specific FSS, mature persons who have only that FSS should be studied.

Functional somatic syndromes: sensitivities and specificities of self-reports of physician diagnosis

OBJECTIVE

Functional somatic syndromes have no laboratory or pathologic abnormalities and so are diagnosed by symptom-based case definitions. However, many studies, including recent ones, have used self-reports of physician diagnosis rather than the case definitions. Our objective was to determine the sensitivities and specificities of self-report of physician diagnosis for chronic fatigue syndrome (CFS), fibromyalgia (FM), irritable bowel syndrome (IBS), panic disorder, and migraine.

METHODS

Each of 312 female patients with incident interstitial cystitis/bladder pain syndrome and matched population-based controls were queried on self-report of physician diagnosis and separately on established case definitions for each of these syndromes.

RESULTS

Using the symptom-based case definitions as standards, we found that self-report of physician diagnosis did not identify 90% of the controls who had CFS, 77% who had FM, 69% who had IBS, 43% who had panic disorder, and 23% who had migraine. In addition, it missed most individuals with multiple syndromes. Findings in one cohort (controls) were confirmed in another (patients with interstitial cystitis/bladder pain syndrome).

CONCLUSIONS

Self-report of physician diagnosis did not identify most of the three most venerable functional somatic syndromes, IBS, FM, and, especially, CFS; nor did it identify substantial minorities of individuals with panic disorder and migraine. Self-report of physician diagnosis was particularly poor in recognizing persons with multiple syndromes. The insensitivity of this diagnostic test has effects on not only prevalence and incidence estimates but also correlates, comorbidities, and case recruitment. To reveal individuals with these syndromes, singly or together, queries of symptoms, not diagnoses, are necessary.

Childhood maltreatment and the response to cognitive behavior therapy for chronic fatigue syndrome

OBJECTIVE

To examine the relationship between a history of childhood maltreatment and the treatment response to cognitive behavior therapy for chronic fatigue syndrome (CFS).

METHODS

A cohort study in a tertiary care clinic with a referred sample of 216 adult patients meeting the Centers for Disease Control and Prevention criteria for CFS, and starting cognitive behavior therapy. Main outcome measures changes between pre- and post therapy in fatigue (Checklist Individual Strength fatigue subscale), disabilities (Sickness Impact Profile total score), physical functioning (short form 36 health survey subscale) and psychological distress (Symptom checklist 90 total score).

RESULTS

At baseline, patients with a history of childhood maltreatment had significantly more limitations and a higher level of psychological distress, but were not more severely fatigued. Change scores on the outcome measures after cognitive behavior therapy did not differ significantly between patients with or without a history of childhood maltreatment, or between the different types of childhood maltreatment. However, patients with a history of childhood maltreatment still experienced more limitations and a higher level of psychological distress after CBT.

CONCLUSIONS

A history of childhood maltreatment was not related to the treatment response of cognitive behavior therapy for CFS. In patients with a history of childhood maltreatment CFS symptoms can be treated with CBT just as well as those without.

Premorbid risk markers for chronic fatigue syndrome in the 1958 British birth cohort

BACKGROUND

Little is known about the aetiology of chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME); prospective studies suggest a role for premorbid mood disorder.

AIMS

To examine childhood and early adult adversity, ill health and physical activity as premorbid risk markers for CFS/ME by 42 years, taking psychopathology into account.

METHOD

Data were from the 1958 British birth cohort, a prospective study from birth to 42 years (n = 11 419). The outcomes were self-reported CFS/ME (n = 127) and operationally defined CFS-like illness (n = 241) at 42 years.

RESULTS

Adjusting for psychopathology, parental physical abuse (odds ratio (OR) = 2.10, 95% CI 1.16-3.81), childhood gastrointestinal symptoms (OR = 1.58, 95% CI 1.00-2.50) and parental reports of many colds (OR = 1.65, 95% CI 1.09-2.50) were independently associated with self-reported CFS/ME. Female gender and premorbid psychopathology were the only risk markers for CFS-like illness, independent of comorbid psychopathology.

CONCLUSIONS

This confirms the importance of premorbid psychopathology in the aetiological pathways of CFS/ME, and replicates retrospective findings that childhood adversity may play a role in a minority.

Do we have an alternative for the Rome III gastroduodenal symptom-based subgroups in functional gastroduodenal disorders? A cluster analysis approach

BACKGROUND

Functional dyspepsia (FD) is a heterogeneous biopsychosocial disorder. The Rome III consensus proposed a subdivision into epigastric pain syndrome and postprandial distress syndrome, based on gastroduodenal symptom pattern only; nausea/vomiting- and belching disorders were classified as separate functional gastroduodenal disorders (FGD). We aimed to investigate an alternative subdivision of FGD, taking into account gastric sensorimotor function, anxiety & depression and 'somatization', besides gastroduodenal symptoms.

METHODS

Gastroduodenal symptom data were available for 857 consecutive FGD patients (Rome II criteria). In a subsample (n=259), additional data were obtained on gastric sensitivity, anxiety, depression and 'somatization'. Two separate cluster analyses were performed. In analysis 1, clustering was based on individual gastroduodenal symptom scores. In analysis 2, gastric sensitivity, anxiety & depression and 'somatization', besides total gastroduodenal symptoms score, were used for clustering.

KEY RESULTS

Analysis 1 identified four clusters, largely supporting the Rome III classification, with early satiation, pain and nausea/vomiting clusters, besides a limited severity cluster (R(2) = 0.32). Analysis 2 suggested a five-cluster solution (R(2) = 0.48). Anxiety, depression and 'somatization' were the most important variables separating the clusters. 'Primary somatization' (with low psychiatric symptom levels) as well as 'secondary somatization' (with high anxiety & depression scores) subgroups were identified, besides three other subgroups characterized by psychiatric/gastroduodenal symptoms, mild anxiety symptoms and limited overall severity, respectively.

CONCLUSIONS & INFERENCES

We propose an alternative to the current subgrouping in FGD that is exclusively based on gastroduodenal symptoms. This may have consequences for future classification of FGD, as well as broader relevance towards the debate on subgrouping 'functional somatic syndromes'.

Neurochemical and neuropharmacological aspects of circadian disruptions: an introduction to asynchronization

Circadian disruptions are common in modern society, and there is an urgent need for effective treatment strategies. According to standard diagnostic criteria, most adolescents showing both insomnia and daytime sleepiness are diagnosed as having behavioral-induced sleep efficiency syndrome resulting from insomnia due to inadequate sleep hygiene. However, a simple intervention of adequate sleep hygiene often fails to treat them. As a solution to this clinical problem, the present review first overviews the basic neurochemical and neuropharmachological aspects of sleep and circadian rhythm regulation, then explains several circadian disruptions from similar viewpoints, and finally introduces the clinical notion of asynchronization. Asynchronization is designated to explain the pathophysiology/pathogenesis of exhibition of both insomnia and hypersomnia in adolescents, which comprises disturbances in various aspects of biological rhythms. The major triggers for asynchronization are considered to be a combination of light exposure during the night, which disturbs the biological clock and decreases melatonin secretion, as well as a lack of light exposure in the morning, which prohibits normal synchronization of the biological clock to the 24-hour cycle of the earth and decreases the activity of serotonin. In the chronic phase of asynchronization, involvement of both wake- and sleep-promoting systems is suggested. Both conventional and alternative therapeutic approaches for potential treatment of asynchronization are suggested.

Factors associated with co-morbid irritable bowel syndrome and chronic fatigue-like symptoms in functional dyspepsia

BACKGROUND

It is unclear which factors explain the high co-morbidity between functional dyspepsia (FD) and other functional somatic syndromes. The aim of this study is to investigate the association between gastric sensorimotor function, psychosocial factors and 'somatization' on the one hand, and co-morbid irritable bowel syndrome (IBS) and chronic fatigue (CF)-like symptoms on the other, in FD.

METHODS

In 259 tertiary care FD patients, we studied gastric sensorimotor function with barostat (sensitivity, accommodation). We measured psychosocial factors (abuse history, alexithymia, trait anxiety, depression, panic disorder) and 'somatization' using self-report questionnaires, and presence of IBS and CF-like symptoms. Hierarchical multiple logistic regression was used to determine which of these factors were independently associated with co-morbid IBS and CF-like symptoms, including testing of potential mediator effects.

KEY RESULTS

Co-morbid IBS or CF-like symptoms respectively were found in 142 (56.8%) and 102 (39.4%) patients; both co-morbidities were not significantly associated (P=0.27). Gastric accommodation (β=0.003, P=0.04) and 'somatization' (β=0.17, P= 0.0003) were independent risk factors for IBS (c=0.74, P<0.0001); the effect of adult abuse (β=0.72, P=0.20) was mediated by 'somatization'. Depression (β=0.16, P=0.008) and 'somatization' (β=0.18, P=0.004) were overlapping risk factors for CF-like symptoms (c=0.83, P<0.0001); the effects of alexithymia and lifetime abuse were mediated by depression and 'somatization', respectively.

CONCLUSIONS & INFERENCES

'Somatization' is a common risk factor for co-morbid IBS and CF-like symptoms in FD and mediates the effect of abuse. Gastric sensorimotor function and depression are specific risk factors for co-morbid IBS and CF-like symptoms, respectively.

Chronic fatigue syndrome in an ethnically diverse population: the influence of psychosocial adversity and physical inactivity

BACKGROUND

Chronic fatigue syndrome (CFS) is a complex multifactorial disorder. This paper reports the prevalence of chronic fatigue (CF) and CFS in an ethnically diverse population sample and tests whether prevalence varies by social adversity, social support, physical inactivity, anxiety and depression.

METHODS

Analysis of survey data linking the Health Survey for England (1998 and 1999) and the Ethnic Minority Psychiatric Illness Rates in the Community (EMPIRIC) study undertaken in 2000. The study population comprised a national population sample of 4,281 people ages 16 to 74 years. CF and CFS were operationally defined on the basis of an interview in the EMPIRIC study, alongside questions about psychosocial risk factors. Previous illnesses were reported in the Health Survey for England during 1998 and 1999, as was physical inactivity.

RESULTS

All ethnic minority groups had a higher prevalence of CFS than the White group. The lowest prevalence was 0.8% in the White group, and it was highest at 3.5% in the Pakistani group (odds ratio (OR), 4.1; 95% confidence interval (95% CI), 1.6 to 10.4). Anxiety (OR, 1.8; 95% CI, 1.4 to 2.2), depression (OR, 1.4; 95% CI, 1.1 to 1.8), physical inactivity (OR, 2.0; 95% CI, 1.1 to 3.8), social strain (OR, 1.24; 95% CI, 1.04 to 1.48) and negative aspects of social support (OR, 2.12; 95% CI, 1.4 to 3.3) were independent risk factors for CFS in the overall sample. Together these risk factors explained ethnic differences in the prevalence of CFS, but no single risk factor could explain a higher prevalence in all ethnic groups.

CONCLUSIONS

The prevalence of CFS, but not CF, varies by ethnic group. Anxiety, depression, physical inactivity, social strain and negative aspects of social support together accounted for prevalence differences of CFS in the overall sample.

Gynecological history in chronic fatigue syndrome: a population-based case-control study

BACKGROUND

Chronic fatigue syndrome (CFS) affects disproportionately more women than men, and the condition is more common at perimenopause. We examined gynecological history events as risk factors for CFS.

METHODS

In a case-control study from a randomly selected population sample from Wichita, Kansas, 36 women with CFS and 48 nonfatigued controls, of similar age, race, and body mass index (BMI), answered a structured gynecological history questionnaire.

RESULTS

CFS cases and controls had the same mean age (51 years) and age at menarche (12 years). Overall, a greater proportion of women with CFS than controls reported pelvic pain unrelated to menstruation (22.2% vs. 1.7%, p = 0.004), endometriosis (36.1% vs. 16.7, %, p = 0.046), and periods of amenorrhea (53.9 % vs. 46.2%, p = 0.06). Compared to controls, women in the CFS group had a higher mean number of pregnancies (2.8 vs 2.0, p = 0.05) and gynecological surgeries (1.8 vs. 1.1, p = 0.05). Similar proportions of the CFS (69.4%) and control (72.9%) groups were menopausal. Although menopausal women in the CFS and control groups had similar mean age (55.5 and 55.8, respectively), menopause occurred about 4.4 years earlier in the CFS group (41.7 years vs. 46.1 years, respectively, p = 0.11). Among menopausal women, 76% of the CFS group reported hysterectomy vs. 54.6% of controls (p = 0.09), and 56% of women with CFS reported oophorectomy vs. 34.3% of controls (p = 0.11).

CONCLUSIONS

The higher prevalence of gynecological conditions and gynecological surgeries in women with CFS highlights the importance of evaluating gynecological health in these patients and the need for more research to clarify the chronologic and the pathophysiological relationships between these conditions and CFS.

Psychiatric aspects of chronic fatigue syndrome and fibromyalgia

Chronic fatigue syndrome and/or fibromyalgia (CFS/FM) consists of highly overlapping, medically unexplained symptoms, including long-lasting fatigue, effort intolerance, cognitive dysfunction, and widespread pain and tenderness. CFS/FM often seems to be triggered by infections and physical trauma, but depression, sleep disturbances, and personality may also be involved. Moreover, dysregulation of the stress system, the immune system, and central pain mechanisms may determine the pathophysiology of the illness, leading to a loss of capacity to adapt to all kind of stressors. CFS/FM patients can be best helped by a pragmatic and individualized approach aimed at adjusting lifestyle and optimizing self-care, which in the long run may contribute to a restoration of physical and mental adaptability. Future psychiatric research into CFS/FM should focus on the complex interrelationships among pain/fatigue, stress/depression, and personality, as well as on processes of therapeutic change and the advantages of customized treatment.

Perspectives on fatigue from the study of chronic fatigue syndrome and related conditions

Fatigue is a symptom whose causes are protean and whose phenotype includes physical, mood, and behavioral components. Chronic fatigue syndrome (CFS) is an illness that has strong biological underpinnings and no definite etiology. Diagnostic criteria established by the Centers for Disease Control and Prevention have helped classify CFS as an overlap of mood, behavioral, and biological components. These include the presence of fatigue for more than 6 months associated with a diminution of functional activity and somatic symptoms, and pain not attributable to a specific diagnosis or disease. Four of the following criteria need to be present: sore throat, impaired memory or cognition, unrefreshing sleep, postexertional fatigue, tender glands, aching stiff muscles, joint pain, and headaches. Many researchers have observed that CFS shares features in common with other somatic syndromes, including irritable bowel syndrome, fibromyalgia, and temporomandibular joint dysfunction. Correlations between inflammation and infection, augmented sensory processing, abnormalities of neurotransmitters, nerve growth factors, low levels of serotonin and norepinephrine, abnormalities of homeostasis of the stress system, and autonomic dysfunction may be hallmarks of CFS. The relative contributions of each of these abnormalities to the profound fatigue associated with CFS need to be explored further to better evaluate and treat the syndrome.

Chronic fatigue syndrome: Is it one discrete syndrome or many? Implications for the "one vs. many" functional somatic syndromes debate

There is a current debate as to whether "functional somatic syndromes" (FSSs) are more similar to or different from each other. While at the same time, there is evidence of heterogeneity within single syndromes. So, it could be that these syndromes are all part of one big process/illness, are discrete in their own right, or that they are heterogeneous collections of different illnesses lumped together by common symptoms but separated by uncommon pathophysiologies. The example of chronic fatigue syndrome (CFS) is instructive. There is evidence to support all three models of understanding. Three recent large studies have suggested that FSSs are both similar and dissimilar at the same time. The solution to the debate is that we need to both "lump" and "split." We need to study both the similarities between syndromes and their dissimilarities to better understand what we currently call the FSSs.