The metabolic syndrome (MetS), which affects one-third [
Obesity is linked to inactivity and though physical activity (PA) is known to impact MetS [
MetS precedes type 2 diabetes (T2D) and cardiovascular disease (CVD). The prevalence of having ≥2 risk factors for CVD is highest among AAs (48.7%) [
In AAs, MetS is directly linked to central and overall obesity [
The MetS symptom cluster leads to the pathogenesis of CVD via bidirectional neuroendocrine and central nervous system mechanisms. Possessing more than 2 components of MetS signifies higher risk than is predicted by its components when analyzed individually and adding more components further concentrates CVD risk. A MetS diagnosis can indicate an adjusted relative risk of CVD outcomes, which is approximately 2-fold [
Mind-body modalities are a diverse group of healthcare practices that represent adjuncts to conventional care of MetS [
Growing evidence suggests that tai chi and qi gong, also considered spinal manipulation therapies, may improve aerobic capacity and reduce stress in as few as one session [
Although the mechanisms underlying the psychological and biological effects of MetS are not well understood, the manifestations of the symptom cluster likely occur through multiple bidirectional autonomic and neuroendocrine pathways. Mind-body therapies may reduce the effects of both
The objective of this paper is to synthesize and summarize existing knowledge on the effectiveness of mind-body therapies on MetS outcomes in AA women. This systematic review critically examines the research of mind-body therapies as complementary therapies for management of the MetS focusing on single components and/or the aggregate of symptoms that make up the MetS rather than solely focusing on studies that have investigated all 5 components of the MetS.
A systematic search of eight databases was conducted along with a search of the reference list of the retrieved publications, in order to identify published papers addressing the topic. The databases searched were PubMed/Medline, CINAHL (EBSCO), Web of Science, Dissertations & Theses (ProQuest), Sociological Abstracts (ProQuest), Academic Search Complete (EBSCO), AMED (the Allied and Complementary Medicine Database) (EBSCO), and the Cochrane Library. The articles included were limited to those published from 2000 to 2016 that were written in English and involved adult aged female participants of ages 18–64 years. Medical Subject Headings (MeSH) and equivalent controlled vocabulary and keywords were utilized in each database as appropriate. The search was broken into two concept groups. One group encompassed the terminology used to describe “African Americans”; the other covered the terms relevant to “yoga” and “tai chi.” The last search was conducted on December 1, 2016.
For the purposes of this systematic review, mind-body therapies were limited to yoga, tai chi, and qigong; breathing exercises; mindfulness-based techniques; and any form of meditation. Studies that assessed one of the defined mind-body therapies alone or as an adjuvant to conventional treatment in human subjects with the MetS were included. Trials were excluded if the study was aimed at the development of methodology of mind-body therapy procedures without clinical outcomes, reported no data or statistical comparisons, or assessed healthy subjects only. Trials were included if the study examined a mind-body modality as part of a complex intervention (i.e., combining a mind-body therapy with other complementary modalities) or if the study was limited to only components of the MetS (i.e., hypertension or insulin sensitivity alone). Studies before 2000, abstracts, qualitative study designs, and those involving children, males only, pregnant women, individuals with a history of psychosis, and older adults were excluded. Dissertations/theses were initially screened for relevance but excluded in the final review, as they were not published articles. We included randomized controlled trials (RCTs) involving AA adult women, ages 18–64, at risk of MetS. The comparison group was no intervention or minimal intervention and we included trials that involved multifactorial interventions. Outcomes of interest were determined using PICOS (population, intervention, comparison intervention, outcome measures, and study design) criteria where major MetS, chronic disease, and CVD risk factors were characterized with the following inclusion criteria: blood pressure, blood lipids, type 2 diabetes, BMI, waist circumference, chronic disease, mental health, quality of life, stress, depression, physical activity, behavior, glucose, insulin, autoimmune, and inflammation.
Two independent reviewers validated, extracted, and recorded relevant study data using predefined criteria. Risk of bias was assessed using the Cochrane classification, and the quality of all studies was independently assessed using the Cochrane scoring criteria [
The database searches identified 721 potentially relevant articles, of which 430 remained after deduplication (exclusion of duplicated articles). Further, 425 were screened, assessed for full-text eligibility, and excluded resulting in five (5) trials being included in this paper. A schematic of the excluded studies as well as the reasons for exclusion is outlined in Figure
Characteristics of included studies.
References | Design | Mean age, sample size, Metabolic syndrome-related condition | Intervention-treatment regimen | Main outcome measures | Main results | Comments |
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Bernstein et al. 2014 [ | RCT | Mean age = 56 | Low-intensity exercise; mindfulness; relaxation techniques: meditation and guided imagery | Weight/BMI; HbA1c; waist circumference, blood pressure, CRP, fasting insulin; PSS, physical activity | No significant treatment effect of the lifestyle intervention on weight (0.3 kg; 95% CI: −1.4 to 2.0 kg, | 92% class attendance; trends towards improvement in healthy eating and cooking habits were seen |
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Cox et al. 2013 [ | RCT | Mean age = 44.5 | Diabetes prevention program + guided relaxation; diaphragmatic breathing; mindfulness | Weight loss; stress-PSS; stress-salivary cortisol | Stronger positive association between group attendance and weight loss in the treatment group ( | 86% retention rates; weight loss associated with total sessions attended ( |
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Jefferson 2010 [ | RCT | Mean age = 52.9 | Therapeutic chair massage; patient-taught diaphragmatic breathing | Blood pressure; anxiety-STAI; stress-PSS | Significant differences in systolic blood pressure ( | No significant differences in PSS between the massage groups (6-week, |
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Webb et al. 2000 [ | RCT | Mean age = 33.5 | Seven-muscle group progressive relaxation | Blood pressure; Physical, Interpersonal, Psychological Strain scores | Within-subjects changes over time in interpersonal strain scores ( | Between-groups interactions greater reductions in interpersonal strain ( |
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Young and Stewart 2006 [ | Cluster | Mean age = 48.3 | Alternating weekly low-intensity stretching classes and health education | Blood pressure; cholesterol-HDL-C | Exercise participants attended an average of 21.6% of classes, whereas the stretch and health participants attended an average of 31.5% of classes ( | Participants who did not return for follow-up were younger than those who did return (47.3 ± 8.7 versus 51.1 ± 9.6, |
RCT: randomized controlled trial; PSS: Cohen’s Perceived Stress Scale; STAI: State Trait Anxiety Inventory; HDL-C: high density lipoprotein-cholesterol.
Diagram of review process and trial selection.
Risk of bias summary.
Author, year | Title of trial | Reference number | Modified bias score | Random sequence generation | Allocation concealment | Incomplete outcome data | Selective reporting | Blinding of outcome assessment |
---|---|---|---|---|---|---|---|---|
Bernstein et al. 2014 | Management of Pre-Diabetes through Lifestyle Modification in Overweight and Obese African-American Women: The Fitness, Relaxation, and Eating to Stay Healthy (FRESH) Randomized Controlled Trial | [ | 4 | Low | Low | Low | Low | Not judged |
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Cox et al. 2013 | Stress Management-Augmented Behavioral Weight Loss Intervention for African American Women: A Pilot, Randomized Controlled Trial | [ | 3 | Low | Low | Low | Unclear | Not judged |
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Jefferson 2010 | Exploring Effects of Therapeutic Massage and Patient Teaching in the Practice of Diaphragmatic Breathing on Blood Pressure, Stress, and Anxiety in Hypertensive African-American Women: An Intervention Study | [ | 1 | High | High | High | Low | Not judged |
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Webb et al. 2000 | A Progressive Relaxation Intervention at the Worksite for African-American Women | [ | 1 | High | High | High | Low | Not judged |
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Young and Stewart | A Church-Based Physical Activity Intervention for African American Women | [ | 2 | High | High | Unclear | Unclear | Not judged |
Details of studies included in this review are given in Table
Bernstein and colleagues (modified score = 4) conducted an RCT of a lifestyle modification program using a two-group, parallel design in overweight and obese AA women with prediabetes. Subjects (
Jefferson (modified score = 1) evaluated the efficacy of a therapeutic chair massage intervention versus diaphragmatic breathing as an attention control in AA women with hypertension in a randomized study over the course of 6 weeks (
Cox and colleagues (modified score = 3) examined the effects of a lifestyle modification intervention—Diabetes Prevention Program (DPP) Lifestyle Balance intervention using a randomized, controlled, design. The standard DPP lifestyle intervention was augmented with stress management strategies including relaxation techniques—progressive muscle relaxation, diaphragmatic breathing, and mindfulness. AA female subjects (
Young and Stewart (modified score = 2) evaluated the effectiveness of a 6-month aerobic exercise intervention versus a stretching and health lecture intervention in a study of 196 AA women attending churches (
Significant differences were not seen in physical activity levels [
Webb and colleagues (modified score = 1) examined the efficacy of a 7-muscle group progressive relaxation intervention versus set aside time for relaxation in AA women (
The authors screened 430 studies and identified five trials that randomized 378 participants in studies of six-week to six-month duration. Only 3 of these papers provided usable data for meta-analysis. For the remaining studies, either no CIs or standard deviations for the intervention or control group were included. We identified no ongoing studies.
The included RCTs measured outcomes associated with MetS and cardiometabolic disease but they were short term. There were no significant differences between treatment groups observed for BMI, waist circumference, fasting glucose, insulin resistance, cholesterol, and hs-CRP in any of the studies. There were some favorable effects on blood pressure in two trials (the progressive muscle relaxation intervention group [
This review included adults who were at different levels of CVD risk and included AA women. All trials were published in the USA. None of the included studies reported on the sustained effects of mind-body interventions on MetS and CVD risk, but this may be because the included studies were small, with short-term follow-up. Only one of five included trials reported on the full spectrum of MetS outcomes including waist circumference, blood pressure, lipid profile, and fasting glucose [
Indeed, RCTs often use various outcome measures of patient symptoms to quantify the same concepts, limiting comparison across studies. We were not able to examine the effects of baseline CVD risk or the duration of mind-body therapies because of the limited number of trials included. This review identified only five trials, two of which had questionable applicability, as they did not examine the efficacy of a mind-body therapy listed in our trial selection criteria [
The results of this review should be treated with caution since the included trials were at a high risk of bias. In 3 of the included studies, the methods of the random sequence generation were not stated or unclear. In the same 3 trials, the details of allocation concealment were not provided. None of the included studies reported that the outcome assessors were blind. However, it is difficult, if not impossible, to blind participants and personnel to behavioral interventions such as mind-body therapies. While there remains a lack of rigorous trials that apply adequate methodology, including the use of blinding and placebo treatments, given that trials with inadequate levels of blinding are likely to show exaggerated treatment effects, the nature of mind-body therapies makes it seemingly impossible to blind subjects to the intervention or to develop a placebo.
We judged risk of bias related to incomplete outcome data as low in 3 of the 5 included studies. For all studies, we judged the risk of other biases as unclear as there was insufficient information to judge. This review was also at risk of small-study bias since the included studies were relatively small. Limitations of systematic reviews, including the current paper, relate to any potential incompleteness of the reviewed studies. This effect may result from publication bias given that negative studies tend to remain unpublished. In addition, we were unable to examine the effects of publication bias in funnel plots because of the limited number of trials included. Nonetheless, small trials are often carried out with less rigor methodologically speaking, are more likely to be conducted in selected populations, and have been shown to report larger beneficial effects than larger trials [
In this review, we conducted a comprehensive search across major databases for interventions involving mind-body therapies for AA female populations. Two review authors independently performed screening, inclusion and exclusion, data abstraction, data entry, and analysis. Our decision to include trials that involved mind-body therapies in combination with other behavioral interventions introduced the possibility for potential confounding effects of other behavioral approaches on our outcomes. This was done to expand the number of trials eligible for inclusion. The inclusion of studies focusing on clinical outcomes related to single components of the MetS may be a limitation; however, the inclusion of trials examining only certain cardiometabolic measures would not provide reliable data on the clinical effectiveness of mind-body therapies in improving the symptom cluster that comprises the MetS as a whole. In addition, the small number of trials on which this review was based, limitations in the reporting of methodology, a high risk of bias in most studies, and sparse or no data for our outcomes mean that the findings of this review are currently extremely limited.
Only five trials met the inclusion criteria for our review and only one reported our primary outcomes. There was considerable heterogeneity between the included trials for outcomes including blood pressure meaning that meta-analysis was not possible. Therefore, any findings with regard to this outcome can only be suggestive. None of the studies indicated the use of ambulatory blood pressure monitoring over the course of the study. Measurement of blood pressure only at study intervals might have underestimated the efficacy of the mind-body interventions in lowering this key component/symptom of the MetS. None of the included studies reported on triglycerides, occurrence of type 2 diabetes, or depressive symptoms. The trials in this review were also at overall serious risk of bias and, as such, results should be treated with caution. Mind-body therapies may carry practical advantages as therapeutic interventions for managing the symptom cluster associated with the MetS. However, there are currently few randomized controlled trials that meet our inclusion criteria to examine the effects of mind-body therapies for the prevention and management of MetS. At present, there is a shortage of large, long-term trials on the effectiveness of mind-body therapies for the primary prevention of MetS disease in AA women at risk for cardiometabolic diseases. Furthermore, we found only one trial that measured MetS-associated outcomes in AA women. As such, high-quality, large trials with long-term follow-up that measures a broader range of outcomes are needed in order to determine the effectiveness of mind-body therapies.
There is a need to identify cost-effective prevention and management strategies for the MetS that address the multiple interrelated factors underlying this complex and high-risk symptom cluster. No such research has been conducted in this regard with respect to mind-body therapies in this vulnerable population. Current clinical practice guidelines indicate lifestyle modifications as the recommended therapy for prehypertension, as well as other indicators of the MetS. Given the positive effects of mind-body therapies on cardiometabolic components, these modalities most likely would be of benefit to individuals with MetS. The current paper provides healthcare practitioners with information that could be used in decision-making about recommendations involving mind-body practices. In light of the important role of psychosocial factors in the development of insulin resistance, T2D, and other chronic diseases, the influence of sympathetic activation in the pathogenesis of insulin resistant states and the bidirectional relationships of these and other insulin resistance related risk factors and mind-body therapies may hold promise for both the prevention and treatment of the MetS. Because RCTs remain the “gold standard” in biomedical research, this paper highlights the need for such trials of mind-body therapies with regard to the management of the MetS, given the relative absence of such studies in the literature, as well as the mechanisms of action involved in mind-body therapies.
The authors declare that they have no conflicts of interest.
Ms. Sheffield received financial support from the National Institute of Nursing Research under Award no. T32NR007091 (MPIs: S. Santacroce, J. Leeman). Dr. Johnson received financial support from an internal grant at Virginia Commonwealth University School of Nursing.