Qigong for the primary prevention of cardiovascular disease

BACKGROUND

Two major determinants of cardiovascular disease (CVD) are a sedentary lifestyle and stress. Qigong involves physical exercise, mind regulation and breathing control to restore the flow of Qi (a pivotal life energy). As it is thought to help reduce stress and involves exercise, qigong may be an effective strategy for the primary prevention of CVD.

OBJECTIVES

To determine the effectiveness of qigong for the primary prevention of CVD.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (November 2014, Issue 10 of 12); MEDLINE (Ovid) (1946 to 2014 October week 4); EMBASE Classic + EMBASE (Ovid) (1947 to 2014 November 4); Web of Science Core Collection (1970 to 31 October 2014); Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment Database and Health Economics Evaluations Database (November 2014, Issue 4 of 4). We searched several Asian databases (inception to July 2013) and the Allied and Complementary Medicine Database (AMED) (inception to December 2013), as well as trial registers and reference lists of reviews and articles; we also approached experts in the field and applied no language restrictions in our search.

SELECTION CRITERIA

Randomised controlled trials lasting at least three months involving healthy adults or those at high risk of CVD. Trials examined any type of qigong, and comparison groups provided no intervention or minimal intervention. Outcomes of interest included clinical CVD events and major CVD risk factors. We did not include trials that involved multi-factorial lifestyle interventions or weight loss.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion. Two review authors extracted data from included studies and assessed the risk of bias.

MAIN RESULTS

We identified 11 completed trials (1369 participants) and one ongoing trial. Trials were heterogeneous in participants recruited, qigong duration and length of follow-up periods. We were unable to ascertain the risk of bias in nine trials published in Chinese, as insufficient methodological details were reported and we were unable to contact the study authors to clarify this.We performed no meta-analyses, as trials were small and were at significant risk of bias. Clinical events were detailed in subsequent reports of two trials when statistically significant effects of qigong were seen for all-cause mortality, stroke mortality and stroke incidence at 20 to 30 years after completion of the trials. However, these trials were designed to examine outcomes in the short term, and it is not clear whether qigong was practised during extended periods of follow-up; therefore effects cannot be attributed to the intervention. None of the included studies reported other non-fatal CVD events.Six trials provided data that could be used to examine the effects of qigong on blood pressure. Reductions in systolic blood pressure (SBP) and diastolic blood pressure (DBP) were seen in three and two trials, respectively. Three trials examined the effects of qigong on blood lipids when favourable effects were seen in one trial for total cholesterol, low-density lipoprotein (LDL) cholesterol and triglycerides, and two trials showed favourable effects on high-density lipoprotein (HDL) cholesterol. The only trial considered at low risk of selection and detection bias did not demonstrate statistically significant effects on CVD risk factors with qigong, but this study was small and was underpowered. None of the included studies reported incidence of type 2 diabetes (T2D), adverse events, quality of life or costs.

AUTHORS' CONCLUSIONS

Currently, very limited evidence is available on the effectiveness of qigong for the primary prevention of CVD. Most of the trials included in this review are likely to be at high risk of bias, so we have very low confidence in the validity of the results. Publication of the ongoing trial will add to the limited evidence base, but further trials of high methodological quality with sufficient sample size and follow-up are needed to be incorporated in an update of this review before the effectiveness of qigong for CVD prevention can be established.

Laetrile treatment for cancer

BACKGROUND

Laetrile is the name for a semi-synthetic compound which is chemically related to amygdalin, a cyanogenic glycoside from the kernels of apricots and various other species of the genus Prunus. Laetrile and amygdalin are promoted under various names for the treatment of cancer although there is no evidence for its efficacy. Due to possible cyanide poisoning, laetrile can be dangerous.

OBJECTIVES

To assess the alleged anti-cancer effect and possible adverse effects of laetrile and amygdalin.

SEARCH METHODS

We searched the following databases: CENTRAL (2014, Issue 9); MEDLINE (1951-2014); EMBASE (1980-2014); AMED; Scirus; CINAHL (all from 1982-2015); CAMbase (from 1998-2015); the MetaRegister; the National Research Register; and our own files. We examined reference lists of included studies and review articles and we contacted experts in the field for knowledge of additional studies. We did not impose any restrictions of timer or language.

SELECTION CRITERIA

Randomized controlled trials (RCTs) and quasi-RCTs.

DATA COLLECTION AND ANALYSIS

We searched eight databases and two registers for studies testing laetrile or amygdalin for the treatment of cancer. Two review authors screened and assessed articles for inclusion criteria.

MAIN RESULTS

We located over 200 references, 63 were evaluated in the original review, 6 in the 2011 and none in this update. However, we did not identify any studies that met our inclusion criteria.

AUTHORS' CONCLUSIONS

The claims that laetrile or amygdalin have beneficial effects for cancer patients are not currently supported by sound clinical data. There is a considerable risk of serious adverse effects from cyanide poisoning after laetrile or amygdalin, especially after oral ingestion. The risk-benefit balance of laetrile or amygdalin as a treatment for cancer is therefore unambiguously negative.

Feverfew for preventing migraine

BACKGROUND

This review is an update of a previously published review in the Cochrane Database of Systematic Reviews on 'Feverfew for preventing migraine' (2004, Issue 1). Feverfew (Tanacetum parthenium L.) extract is a herbal remedy, which has been used for preventing attacks of migraine.

OBJECTIVES

To systematically review the evidence from double-blind randomised controlled trials (RCTs) assessing the clinical efficacy and safety of feverfew monopreparations versus placebo for preventing migraine.

SEARCH METHODS

For this updated version of the review we searched CENTRAL, MEDLINE, EMBASE and AMED to January 2015. We contacted manufacturers of feverfew and checked the bibliographies of identified articles for further trials.

SELECTION CRITERIA

We included randomised, placebo-controlled, double-blind trials assessing the efficacy of feverfew monopreparations for preventing migraine in patients of any age. We included trials using clinical outcome measures, while we excluded trials focusing exclusively on physiological parameters. There were no restrictions regarding the language of publication.

DATA COLLECTION AND ANALYSIS

We systematically extracted data on patients, interventions, methods, outcome measures, results and adverse events. We assessed risk of bias using the Cochrane 'Risk of bias' tool and evaluated methodological quality using the Oxford Quality Scale developed by Jadad and colleagues. Two review authors (BW and MHP for this update, MHP and EE for the original version) independently selected studies, assessed methodological quality and extracted data. We resolved disagreements concerning evaluation of individual trials through discussion.

MAIN RESULTS

We identified one new study for this update, resulting in six trials (561 patients) meeting the inclusion criteria. Five of the six trials reported on the main outcome, migraine frequency. Although five of the trials were generally of good methodological quality, all studies were either of unclear or high risk of bias with regards to sample size. Pooled analysis of the results was not possible due to the lack of common outcome measures and heterogeneity between studies in terms of participants, interventions and designs.The most recent trial added to this version of the review is rigorous and larger (n = 218), using a stable feverfew extract at a dose determined by a previous dose-finding trial. It reports that feverfew reduced migraine frequency by 1.9 attacks from 4.8 to 2.9 and placebo by 1.3 from to 4.8 to 3.5 per month, resulting in a difference in effect between feverfew and placebo of 0.6 attacks per month. For the secondary outcome measures intensity and duration of migraine attacks, incidence and severity of nausea and vomiting, and global assessment no statistically significant differences were reported. Results of previous trials are not convincing: three trials reporting positive effects of feverfew are all of small sample size (17 to 60 participants), while two rigorous trials (n = 50, 147) did not find significant differences between feverfew and placebo. Only mild and transient adverse events, most commonly gastrointestinal complaints and mouth ulcers, were reported in the included trials.

AUTHORS' CONCLUSIONS

Since the last version of this review, one larger rigorous study has been included, reporting a difference in effect between feverfew and placebo of 0.6 attacks per month. This adds some positive evidence to the mixed and inconclusive findings of the previous review. However, this constitutes low quality evidence, which needs to be confirmed in larger rigorous trials with stable feverfew extracts and clearly defined migraine populations before firm conclusions can be drawn. It appears from the data reviewed that feverfew is not associated with any major safety concerns.

Efficient transformation and artificial miRNA gene silencing in Lemna minor

Despite rapid doubling time, simple architecture and ease of metabolic labelling, a lack of genetic tools in the Lemnaceae (duckweed) has impeded the full implementation of this organism as a model for biological research. Here, we present technologies to facilitate high-throughput genetic studies in duckweed. We developed a fast and efficient method for producing Lemna minor stable transgenic fronds via Agrobacterium-mediated transformation and regeneration from tissue culture. Additionally, we engineered an artificial microRNA (amiRNA) gene silencing system. We identified a Lemna gibba endogenous miR166 precursor and used it as a backbone to produce amiRNAs. As a proof of concept we induced the silencing of CH42, a magnesium chelatase subunit, using our amiRNA platform. Expression of CH42 in transgenic L. minor fronds was significantly reduced, which resulted in reduction of chlorophyll pigmentation. The techniques presented here will enable tackling future challenges in the biology and biotechnology of Lemnaceae.

The efficacy of glucomannan supplementation in overweight and obesity: a systematic review and meta-analysis of randomized clinical trials

OBJECTIVE

The increased prevalence of obesity has resulted in the current high popularity of dietary supplements marketed as weight reducing agents. The efficacy of most of these supplements is not established. The soluble fiber, glucomannan, is often recommended for weight loss. The aim of this systematic review is to evaluate the evidence for or against the efficacy of glucomannan in body weight reduction.

METHODS

Electronic searches were conducted in Medline, Embase, Amed, and The Cochrane Library. Hand searches of bibliography were also conducted. Outcomes of interest were body weight and body mass index. Studies involving only overweight and/or obese participants were included. Two reviewers independently determined the eligibility of studies and assessed the reporting quality of included randomized controlled trials (RCTs), using the CONSORT and PRISMA guidelines.

RESULTS

Eighteen trials were identified, and 9 were included. There was a variation in the reporting quality of the included RCTs. A meta-analysis (random effect model) of 8 RCTs revealed a nonstatistically significant difference in weight loss between glucomannan and placebo (mean difference [MD]: -0.22 kg; 95% confidence interval [CI], -0.62, 0.19; I(2) = 65%). Adverse events included abdominal discomfort, diarrhea, and constipation.

CONCLUSION

The evidence from available RCTs does not show that glucomannan intake generates statistically significant weight loss. Future trials should be more rigorous and better reported.

Acupuncture for treating acute ankle sprains in adults

BACKGROUND

An acute ankle sprain is a sudden-onset injury of one or more of the ankle ligaments. It is one of the most common musculoskeletal injuries in the general population as well as in athletes. In some countries, such as China and Korea, acupuncture is frequently used in the treatment of ankle sprains, either as a single treatment or a secondary intervention accompanied by standard medical treatment.

OBJECTIVES

To assess the effects (benefits and harms) of acupuncture for the treatment of ankle sprains in adults.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (May 2013), the Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 4), MEDLINE (1948 to May week 2 2013), EMBASE (1980 to May week 2 2013), China National Knowledge Infrastructure databases (1994 to August week 4 2013), the Cumulative Index to Nursing and Allied Health Literature (1937 to May 2013), the Allied and Complementary Medicine Database (1985 to May 2013), Science Links Japan (1996 to August week 4 2013), several Korean medical databases (August week 4 2013), the World Health Organization International Clinical Trials Registry Platform (August week 4 2013), the bibliographic references of included trials and conference proceedings.

SELECTION CRITERIA

We included randomised and quasi-randomised controlled trials involving adults with acute ankle sprains. We included all types of acupuncture practices, such as needle acupuncture, electroacupuncture, laser acupuncture, pharmacoacupuncture, non-penetrating acupuncture point stimulation (e.g. acupressure and magnets) and moxibustion. Acupuncture could be compared with control (no treatment or placebo) or another standard non-surgical intervention.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened the search results, assessed trial eligibility, assessed risk of bias and extracted data from the included trials. We calculated risk ratios (RRs) for dichotomous outcomes and mean differences for continuous outcomes. We conducted meta-analyses using the fixed-effect method or, where appropriate, the random-effects method, and used 95% confidence intervals (CI) throughout.

MAIN RESULTS

We included a total of 20 heterogeneous studies (2012 participants with acute ankle sprains); three of which included more than one comparison. Seventeen trials were conducted in China. All of the studies had a high risk of bias due to lack of blinding. The results may also have been affected by selection bias, particularly as five studies were quasi-randomised controlled trials and 12 studies gave no information on their method of randomisation. Of our three prespecified primary outcomes, only cure rate was reported by the majority of studies. No study reported on patient-reported assessment of function and only one reported on adverse events (in which three participants receiving a control intervention experienced skin problems from over-the-counter Chinese herbal patches). The other 19 studies did not record or report on adverse events. We assessed the quality of evidence for cure rates as very low for all comparisons, which means we are very uncertain about the reliability of any of the estimates.The single study comparing acupuncture treatment with no treatment found acupuncture to be more effective with regard to cure rate at five days (31/31 versus 1/30; RR 20.34, 95% CI 4.27 to 96.68). Acupuncture plus another standard treatment versus that standard treatment alone was tested in eight studies; with cure rate data available for seven. Most of these studies reported higher cure rates in the acupuncture plus another standard treatment group than in the standard treatment alone group. However, while the results of an exploratory meta-analysis of cure rate data from eight trials testing acupuncture versus no acupuncture tended to favour acupuncture, the results were very inconsistent across the studies and the estimated effect was very imprecise (383/396 versus 272/355; RR 1.32, 95% CI 0.95 to 1.84; P value = 0.1; I(2) = 98%).Fourteen studies compared acupuncture with a variety of other non-surgical treatments, such as Chinese drug patches, hot and cold water, ice packs, oral Chinese herbal medicine and elastic bandage. Some studies found in favour of acupuncture, some in favour of the other treatment and some found a lack of evidence for a difference between the two interventions under test. The results of an exploratory meta-analysis of cure rate data from 11 trials testing acupuncture versus another non-surgical intervention tended to slightly favour acupuncture, but these were not statistically significant and the data were very heterogeneous (404/509 versus 416/497; RR 1.07, 95% CI 0.94 to 1.22; P value = 0.30; I(2) = 92%).

AUTHORS' CONCLUSIONS

The currently available evidence from a very heterogeneous group of randomised and quasi-randomised controlled trials evaluating the effects of acupuncture for the treatment of acute ankle sprains does not provide reliable support for either the effectiveness or safety of acupuncture treatments, alone or in combination with other non-surgical interventions; or in comparison with other non-surgical interventions. Future rigorous randomised clinical trials with larger sample sizes will be necessary to establish robust clinical evidence concerning the effectiveness and safety of acupuncture treatment for acute ankle sprains.

Acupuncture for surgical conditions: an overview of systematic reviews

AIM

Several systematic reviews (SRs) of acupuncture for surgical conditions have recently been published with sometimes contradicting results. The aim of this overview was to summarise recent SRs of acupuncture for surgical conditions.

METHOD

Thirteen electronic databases were searched for relevant reviews published since 2000. Data were extracted by two independent reviewers according to predefined criteria.

RESULTS

Twelve SRs met our inclusion criteria. They related to the prevention or treatment of postoperative nausea and vomiting as well as to surgical or postoperative pain. Their results were far from uniform, and several caveats need to be considered.

CONCLUSION

The evidence is insufficient to suggest that acupuncture is an effective intervention in surgical settings. More rigorous research seems warranted. This protocol was registered with PROSPERO database (registration number: CRD42013004817).

Yoga for the primary prevention of cardiovascular disease

BACKGROUND

A sedentary lifestyle and stress are major risk factors for cardiovascular disease (CVD). Since yoga involves exercise and is thought to help in stress reduction it may be an effective strategy in the primary prevention of CVD.

OBJECTIVES

To determine the effect of any type of yoga on the primary prevention of CVD.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (2013, Issue 11) in The Cochrane Library; MEDLINE (Ovid) (1946 to November Week 3 2013); EMBASE Classic + EMBASE (Ovid) (1947 to 2013 Week 48); Web of Science (Thomson Reuters) (1970 to 4 December 2013); Database of Abstracts of Reviews of Effects (DARE), Health Technology Assessment Database and Health Economics Evaluations Database (Issue 4 of 4, 2013) in The Cochrane Library. We also searched a number of Asian databases and the Allied and Complementary Medicine Database (AMED) (inception to December 2012). We searched trial registers and reference lists of reviews and articles, and approached experts in the field. We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials lasting at least three months involving healthy adults or those at high risk of CVD. Trials examined any type of yoga and the comparison group was no intervention or minimal intervention. Outcomes of interest were clinical CVD events and major CVD risk factors. We did not include any trials that involved multifactorial lifestyle interventions or weight loss.

DATA COLLECTION AND ANALYSIS

Two authors independently selected trials for inclusion, extracted data and assessed the risk of bias.

MAIN RESULTS

We identified 11 trials (800 participants) and two ongoing studies. Style and duration of yoga differed between trials. Half of the participants recruited to the studies were at high risk of CVD. Most of studies were at risk of performance bias, with inadequate details reported in many of them to judge the risk of selection bias.No study reported cardiovascular mortality, all-cause mortality or non-fatal events, and most studies were small and short-term. There was substantial heterogeneity between studies making it impossible to combine studies statistically for systolic blood pressure and total cholesterol. Yoga was found to produce reductions in diastolic blood pressure (mean difference (MD) -2.90 mmHg, 95% confidence interval (CI) -4.52 to -1.28), which was stable on sensitivity analysis, triglycerides (MD -0.27 mmol/l, 95% CI -0.44 to -0.11) and high-density lipoprotein (HDL) cholesterol (MD 0.08 mmol/l, 95% CI 0.02 to 0.14). However, the contributing studies were small, short-term and at unclear or high risk of bias. There was no clear evidence of a difference between groups for low-density lipoprotein (LDL) cholesterol (MD -0.09 mmol/l, 95% CI -0.48 to 0.30), although there was moderate statistical heterogeneity. Adverse events, occurrence of type 2 diabetes and costs were not reported in any of the included studies. Quality of life was measured in three trials but the results were inconclusive.

AUTHORS' CONCLUSIONS

The limited evidence comes from small, short-term, low-quality studies. There is some evidence that yoga has favourable effects on diastolic blood pressure, HDL cholesterol and triglycerides, and uncertain effects on LDL cholesterol. These results should be considered as exploratory and interpreted with caution.

Pyruvate supplementation for weight loss: a systematic review and meta-analysis of randomized clinical trials

BACKGROUND

Several slimming aids being sold as food supplements are widely available. One of them is pyruvate. Its efficacy in causing weight reduction in humans has not been fully established. The objective of this systematic review was to examine the efficacy of pyruvate in reducing body weight.

METHODS

Electronic and nonelectronic searches were conducted to identify all relevant human randomized clinical trials. The bibliographies of all located articles were also searched. No restrictions in language or time were applied. Two independent reviewers extracted the data according to predefined criteria. A fixed-effect model was used to calculate mean differences (MD) and 95% confidence interval (CI).

RESULTS

Nine trials were identified and 6 were included. All had methodological weaknesses. The meta-analysis revealed a statistically significant difference in body weight with pyruvate compared to placebo (MD: -0.72 kg; 95% CI: -1.24 to -0.20). The magnitude of the effect is small, and its clinical relevance is uncertain. Adverse events included gas, bloating, diarrhea, and increase in low-density lipoprotein (LDL) cholesterol.

CONCLUSION

The evidence from randomized clinical trials does not convincingly show that pyruvate is efficacious in reducing body weight. Limited evidence exists about the safety of pyruvate. Future trials involving the use of this supplement should be more rigorous and better reported.

Acupuncture for treating whiplash associated disorder: a systematic review of randomised clinical trials

The aim of this systematic review was to determine the effectiveness of acupuncture for the treatment of whiplash associated disorder (WAD). Twenty databases were searched from their inceptions to Oct. 2013. Randomised clinical trials (RCTs) of acupuncture (AT), electroacupuncture (EA), or dry needling (DN) for the treatment of WAD were considered eligible. The risk of bias was assessed using the Cochrane tool. Six RCTs met the inclusion criteria. Most of the included RCTs have serious methodological flaws. Four of the RCTs showed effectiveness of AT, AT in addition to usual care (UC), AT in addition to herbal medicine (HM) or EA was more effective than relaxation, sham EA, sham EA in addition to HM or UC for conditioned pain modulation (CPM) and alleviating pain. In one RCT, DN in addition to physiotherapy (PT) had no effect compared to sham-DN in addition to PT for the reduction of pain. None of the RCTs showed that AT/EA/DN was more effective than various types of control groups in reducing disability/function. One RCT did not report between-group comparisons of any outcome measures. The evidence for the effectiveness of AT/EA/DN for the treatment of WAD is limited. Therefore, more research in this area is warranted.

Acupuncture for the treatment of chronic obstructive pulmonary disease: a protocol of a systematic review

INTRODUCTION

This review aims to evaluate the efficacy of acupuncture in the treatment of chronic obstructive pulmonary disease (COPD).

METHODS AND ANALYSIS

14 databases will be searched from their inception. These include PubMed, AMED, EMBASE, the Cochrane Library, seven Korean medical databases (Korean Studies Information Service System, DBPIA, Oriental Medicine Advanced Searching Integrated System, Research Information Service System, KoreaMed, The Town Society of Science Technology and the Korean National Assembly Library), three Chinese Databases (China National Knowledge Infrastructure Database (CNKI), the Chongqing VIP Chinese Science and Technology Periodical Database (VIP), and the Wanfang Database). Only randomised clinical trials (RCTs) using acupuncture for COPD will be considered. The selection of the studies, data abstraction and validation will be performed independently by two researchers. Methodological quality will be assessed with the Cochrane risk of bias.

DISSEMINATION

The systematic review will be published in a peer-reviewed journal. The review will also be disseminated electronically and in print. Updates of the review will be conducted to inform and guide the healthcare practice and policy.

TRIAL REGISTRATION NUMBER

PROSPERO 2013: CRD42013004824.

Tai chi for primary prevention of cardiovascular disease

BACKGROUND

Stress and a sedentary lifestyle are major determinants of cardiovascular disease (CVD). As tai chi involves exercise and can help in stress reduction, it may be effective in the primary prevention of CVD.

OBJECTIVES

To determine the effectiveness of tai chi for the primary prevention of CVD.

SEARCH METHODS

We searched the following electronic databases: the Cochrane Central Register of Controlled Trials (CENTRAL) (Issue 11, 2013); MEDLINE (Ovid) (1946 to November week 3, 2013); EMBASE Classic + EMBASE (Ovid) (1947 to 6 December 2013); Web of Science (Thomson Reuters) (1970 to 6 December 2013); PsycINFO (Ovid) (1806 to December week 1, 2013); Database of Abstracts of Reviews of Effects (DARE); Health Technology Assessment Database and Health Economics Evaluations Database (Issue 4, 2013). We also searched the Allied and complementary Medicine Database (AMED) and OpenGrey (inception to October 2012) and several Asian databases. We searched trial registers and reference lists of reviews for further studies. We applied no language restrictions.

SELECTION CRITERIA

Randomised controlled trials of tai chi lasting at least three months involving healthy adults or adults at high risk of CVD. The comparison group was no intervention or minimal intervention. The outcomes of interest were CVD clinical events and CVD risk factors. We excluded trials involving multifactorial lifestyle interventions or focusing on weight loss to avoid confounding.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, abstracted the data and assessed the risk of bias.

MAIN RESULTS

We identified 13 small trials (1520 participants randomised) and three ongoing trials. All studies had at least one domain with unclear risk of bias, and some studies were at high risk of bias for allocation concealment (one study) and selective reporting (two studies). Duration and style of tai chi differed between trials. Seven studies recruited 903 healthy participants, the other studies recruited people with borderline hypertension or hypertension, elderly people at high risk of falling, and people with hypertension with liver and kidney yin deficiency syndrome.No studies reported on cardiovascular mortality, all-cause mortality or non-fatal events as most studies were short term (all studies had follow-up of one year or less). There was also considerable heterogeneity between studies, which meant that it was not possible to combine studies statistically for cardiovascular risk (I(2) statistic for systolic blood pressure (SBP) was 96%, for diastolic blood pressure (DBP) 96%, for total cholesterol 96%, low-density lipoprotein-cholesterol (LDL-C) 95%, high-density lipoprotein-cholesterol (HDL-C) 98%, triglycerides 75%). Nine trials measured blood pressure, six individual trials found reductions in SBP (reductions ranged from -22.0 mmHg (95% confidence interval (CI) -26.3 to -17.7) to -11.5 mmHg (95% CI -21.5 to -1.46)), two trials found no clear evidence of a difference (however, CIs were wide and an increase or decrease in SBP cannot be ruled out), and one trial found an increase in SBP with tai chi (increase 5.2 mmHg, 95% CI 3.73 to 6.67). A similar pattern was seen for DBP: three trials found a reduction in DBP (reductions ranged from -12.2 mmHg (95% CI -15.8 to -8.7) to -4.43 mmHg (95% CI -7.14 to -1.72)) and three trials found no clear evidence of a difference, however again with wide CIs. Three trials reported lipid levels and two found reductions in total cholesterol, LDL-C and triglycerides (total cholesterol reductions ranged from -1.30 mmol/L (95% CI -1.57 to -1.03) to -0.50 mmol/L (95% CI -0.74 to -0.26): LDL-C reductions ranged from -0.76 mmol/L (95% CI -0.93 to -0.59) to -0.59 mmol/L (95% CI -0.80 to -0.38): triglyceride reductions ranged from -0.46 mmol/L (95% CI -0.62 to -0.30) to -0.37 mmol/L (95% CI -0.67 to-0.07)) and increased HDL-C with the intervention (HDL-C increases ranged from 0.61 mmol/L (95% CI 0.51 to 0.71) to 0.16 mmol/L (95% CI 0.02 to 0.30)), while the third study found no clear evidence of a difference between groups on lipid levels. Quality of life was measured in one trial: tai chi improved quality of life at three months. None of the included trials reported on adverse events, costs or occurrence of type 2 diabetes.

AUTHORS' CONCLUSIONS

There are currently no long-term trials examining tai chi for the primary prevention of CVD. Due to the limited evidence available currently no conclusions can be drawn as to the effectiveness of tai chi on CVD risk factors. There was some suggestion of beneficial effects of tai chi on CVD risk factors but this was not consistent across all studies. There was considerable heterogeneity between the studies included in this review and studies were small and at some risk of bias. Results of the ongoing trials will add to the evidence base but additional longer-term, high-quality trials are needed.