Vitamin and mineral status in chronic fatigue syndrome and fibromyalgia syndrome: A systematic review and meta-analysis.

BACKGROUND: Many chronic fatigue syndrome (CFS) and fibromyalgia syndrome (FMS) patients (35-68%) use nutritional supplements, while it is unclear whether deficiencies in vitamins and minerals contribute to symptoms in these patients. Objectives were (1) to determine vitamin and mineral status in CFS and FMS patients as compared to healthy controls; (2) to investigate the association between vitamin and mineral status and clinical parameters, including symptom severity and quality of life; and (3) to determine the effect of supplementation on clinical parameters. METHODS: The databases PubMed, EMBASE, Web of Knowledge, and PsycINFO were searched for eligible studies. Articles published from January 1st 1994 for CFS patients and 1990 for FMS patients till March 1st 2017 were included. Articles were included if the status of one or more vitamins or minerals were reported, or an intervention concerning vitamins or minerals was performed. Two reviewers independently extracted data and assessed the risk of bias. RESULTS: A total of 5 RCTs and 40 observational studies were included in the qualitative synthesis, of which 27 studies were included in the meta-analyses. Circulating concentrations of vitamin E were lower in patients compared to controls (pooled standardized mean difference (SMD): -1.57, 95%CI: -3.09, -0.05; p = .042). However, this difference was not present when restricting the analyses to the subgroup of studies with high quality scores. Poor study quality and a substantial heterogeneity in most studies was found. No vitamins or minerals have been repeatedly or consistently linked to clinical parameters. In addition, RCTs testing supplements containing these vitamins and/or minerals did not result in clinical improvements. DISCUSSION: Little evidence was found to support the hypothesis that vitamin and mineral deficiencies play a role in the pathophysiology of CFS and FMS, and that the use of supplements is effective in these patients. REGISTRATION: Study methods were documented in an international prospective register of systematic reviews (PROSPERO) protocol, registration number: http://www.crd.york.ac.uk/PROSPERO/display_record.asp?ID=CRD42015032528.

Revealing causal heterogeneity using time series analysis of ambulatory assessments: application to the association between depression and physical activity after myocardial infarction.

OBJECTIVE: Studies in psychosomatic medicine are characterized by analyses that typically compare groups. This nomothetic approach leads to conclusions that apply to the average group member but not necessarily to individual patients. Idiographic studies start at the individual patient and are suitable to study associations that differ between time points or between individuals. We illustrate the advantages of the idiographic approach in analyzing ambulatory assessments, taking the association between depression and physical activity after myocardial infarction as an example. METHODS: Five middle-aged men who had myocardial infarction with mild to moderate symptoms of depression were included in this study. Four of these participants monitored their physical activity and depressive symptoms during a period of 2 to 3 months using a daily self-registration form. The time series of each individual participant were investigated using vector autoregressive modeling, which enables the analysis of temporal dynamics between physical activity and depression. RESULTS: We found causal heterogeneity in the association between depression and physical activity. Participants differed in the predominant direction of effect, which was either from physical activity to depression (n = 1, 85 observations, unstandardized effect size = -0.183, p = .03) or from depression to physical activity (n = 2, 65 and 59 observations, unstandardized effect sizes = -0.038 and -0.381, p < .001 and p = .04). Also, the persistency of effects differed among individuals. CONCLUSIONS: Vector autoregressive models are suitable in revealing causal heterogeneity and can be easily used to analyze ambulatory assessments. We suggest that these models might bridge the gap between science and clinical practice by translating epidemiological results to individual patients.

More than the sum of its parts: meta-analysis and its potential to discover sources of heterogeneity in psychosomatic medicine.

Meta-analyses may contribute to more reliable knowledge about the existence of certain relations in the area of psychosomatic research. Surprisingly, the increasing popularity of meta-analysis is not reflected in the number of meta-analyses of observational studies published in Psychosomatic Medicine. This may be due to the specific difficulties that apply to meta-analyses of observational research. The aim of this paper is to provide a nontechnical overview of the principles of meta-analysis applied to observational research. We will highlight general principles of meta-analysis and discuss the major threats to its validity, with an emphasis on its specific merits and pitfalls for psychosomatic research, using several examples. We conclude that meta-analysis is a relatively simple technique, leaving little reason for not routinely applying it when performing a systematic review. An adequately conducted meta-analysis may not only provide a summary estimate of a certain association, but it has additional value in discovering relevant confounders, mediators, and moderators, as well as identifying areas of research that require more attention.

Symptoms, syndromes, and the value of psychiatric diagnostics in patients who have functional somatic disorders.

Half of all outpatient encounters are precipitated by physical complaints, of which one third to one half are medically unexplained symptoms, and 20% to 25% are chronic or recurrent. Many of the patients suffer from one or more discrete symptoms, whereas others have functional somatic syndromes. Individual symptoms and somatic syndromes are associated with impaired quality of life, increased health care use, and diminished patient and provider satisfaction. This article provides an overview of (1) unexplained symptoms and somatization; (2) limitations of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition in classifying somatoform disorders; (3) predictors of psychiatric comorbidity in patients who have physical symptoms; and (4) measurement and management of symptoms.