Dietary Approaches to Prevent Hypertension Comprehensive lifestyle modification and blood pressure control: a review of the PREMIER trial. Effects of Comprehensive Lifestyle Modification on Diet, Weight, Physical Fitness, and Blood Pressure Control: 18-Month Results of a Randomized Trial The PREMIER intervention helps participants follow the Dietary Approaches to Stop Hypertension dietary pattern and the current Dietary Reference Intakes recommendations. A dietary approach to prevent hypertension: A review of the dietary approaches to stop hypertension (DASH) study Indirect comparisons of competing interventions. Short-term effects of nitrate-rich green leafy vegetables on blood pressure and arterial stiffness in individuals with high-normal blood pressure. Mixed treatment comparison analysis provides internally coherent treatment effect estimates based on overviews of reviews and can reveal inconsistency. Effects of the Dietary Approaches to Stop Hypertension Diet, Exercise, and Caloric Restriction on Neurocognition in Overweight Adults With High Blood Pressure Bias due to selective inclusion and reporting of outcomes and analyses in systematic reviews of randomised trials of healthcare interventions. Effect of polyphenol-rich grape seed extract on ambulatory blood pressure in subjects with pre- and stage I hypertension. Sources of evidence for systematic reviews of interventions in diabetes. Can we rely on the best trial? A comparison of individual trials and systematic reviews Hypertension Intervention Pooling Project. Absence of an effect of high nitrate intake from beetroot juice on blood pressure in treated hypertensive individuals: a randomized controlled trial. Incident dementia and blood pressure lowering in the Hypertension in the Very Elderly Trial cognitive function assessment (HYVET-COG): a double-blind, placebo controlled trial Self-efficacy as a predictor of weight change and behavior change in the PREMIER trial. Dietary Approaches to Stop Hypertension: a summary of study results. DASH Collaborative Research Group. Sugammadex: when should we be giving it? Effects of Diet and Sodium Intake on Blood Pressure: Subgroup Analysis of the DASH-Sodium Trial Effect of the DASH Diet on Pre- and Stage 1 Hypertensive Individuals in a Free-Living Environment A road map for efficient and reliable human genome epidemiology Cardiorespiratory Fitness in Childhood and Adolescence Affects Future Cardiovascular Risk Factors: A Systematic Review of Longitudinal Studies
Elevated blood pressure arises from a combination of environmental and genetic factors and the interactions of these factors . A substantial body of evidence from animal studies , epidemiologic studies , meta-analyses , and r and omized controlled trials has demonstrated that certain dietary patterns and individual dietary elements play a prominent role in the development of hypertension . Changes in diet can lower blood pressure , prevent the development of hypertension , and reduce the risk of hypertension-related complications . Dietary strategies for the prevention of hypertension include reducing sodium intake , limiting alcohol consumption , increasing potassium intake , and adopting an overall dietary pattern such as the DASH ( Dietary Approaches to Stop Hypertension ) diet or a Mediterranean diet . In order to reduce the burden of blood pressure-related complications , efforts that focus on environmental and individual behavioral changes that encourage and promote healthier food choices are warranted The PREMIER trial assessed the aggregate effect on blood pressure ( BP ) of nationally recommended lifestyle modifications in free-living adults with high-normal ( stage 1 ) hypertension . Participants ( N=810 ) were r and omized to the advice-only group ; the established group ( consisting of weight loss , increased physical activity , and reduced sodium and alcohol intake ) ; or the established plus Dietary Approaches to Stop Hypertension ( DASH ) diet group ( consisting of the established interventions in addition to the DASH dietary pattern ) . The primary outcome was change in systolic BP at 6 months . Net of advice only , mean systolic BP declined by 3.7 mm Hg for members of the established group ( p<0.001 ) and 4.3 mm Hg for the established plus DASH group ( p<0.001 ) . The prevalence of hypertension decreased from a baseline of 38 % to 17 % in the established group ( p=0.01 ) and to 12 % in the established plus DASH group ( p<0.001 ) compared with a decrease to 26 % in the advice-only group . The PREMIER trial demonstrated that persons with above-optimal BP and stage 1 hypertension can make multiple lifestyle changes leading to better control of BP Context Can adults make sustained changes in unhealthy lifestyle behaviors ? Content In this multicenter trial , 810 adult volunteers with prehypertension or stage 1 hypertension were r and omly assigned to a multicomponent behavioral intervention group , a group combining the behavioral intervention plus the Dietary Approaches to Stop Hypertension ( DASH ) diet , or an advice only group . At 18 months , participants in both behavioral intervention groups had less hypertension , more weight loss , and better reduction in sodium and fat intake than those receiving advice only . The participants in the DASH diet group also increased their intake of fruits , vegetables , and fiber . Implication s Motivated adults can sustain several lifestyle changes over 18 months , which might reduce their risk for cardiovascular disease . The Editors The public health burden of chronic diseases related to suboptimal diet and physical inactivity is enormous . It has been estimated that these lifestyle factors contribute to approximately 20 % of deaths in the United States ( 1 ) . Incidence of atherosclerotic cardiovascular disease , overweight and obesity , elevated blood pressure and lipid levels , diabetes , osteoporosis , and cancer is increased by unhealthy lifestyles ( 2 - 8 ) . Multiple lifestyle factors , such as physical inactivity ; excessive intake of calories , sodium , saturated fat , and cholesterol ; and inadequate intake of fruits , vegetables , and low-fat dairy products , are etiologically related to the development of these diseases ( 4 , 5 , 8 - 10 ) . To reduce the burden of chronic disease , increased physical activity and changes in diet are needed , yet few intervention studies have attempted to achieve many lifestyle changes simultaneously . The PREMIER r and omized trial tested the effects of 2 multicomponent behavioral interventions on blood pressure ( 11 ) . Both interventions promoted increased physical activity , weight loss , and reduced sodium intake , each of which is recommended by the 2005 Dietary Guidelines Scientific Advisory Committee ( 12 ) . One intervention also added the Dietary Approaches to Stop Hypertension ( DASH ) diet ( 13 ) . This diet , which is high in fruits , vegetables , and low-fat dairy products and low in saturated fat , total fat , and cholesterol , meets each of the major nutrient recommendations that were established by the Institute of Medicine ( 14 - 18 ) . We report the effects of the PREMIER interventions on lifestyle changes and blood pressure status at 18 months . The main results of PREMIER , namely change in blood pressure at 6 months , were reported previously ( 11 ) . Methods The PREMIER study design and rationale ( 19 ) and intervention methods ( 11 ) have been described previously . The institutional review boards at each clinical center ; an external protocol review committee appointed by the National Heart , Lung , and Blood Institute ( NHLBI ) ; and the NHLBI review ed and approved the protocol ( available at www.kpchr.org/public/premier/intervention/default.asp ) . The NHLBI also appointed a data and safety monitoring board to monitor the trial . Each participant provided written informed consent . The trial was conducted from January 2000 through November 2002 . Study Participants Participants were generally healthy adults , age 25 years or older , who had prehypertension or stage 1 hypertension and met the Joint National Committee VI ( JNC VI ) criteria for a 6-month trial of nonpharmacologic therapy ( 2 ) . Targeted recruitment methods were used to ensure adequate representation of clinical ly important subgroups , in particular , African-American persons . Specific methods varied from site to site but included direct mailings , radio and newspaper advertisements , and networking within the local African-American communities . Eligibility criteria included not taking antihypertensive medication and having a systolic blood pressure of 120 to 159 mm Hg and a diastolic blood pressure of 80 to 95 mm Hg , based on the average of 3 screening visits . Persons with prehypertension ( systolic blood pressure of 120 to 139 mm Hg or diastolic blood pressure of 80 to 89 mm Hg ) were included because of the excess risk for cardiovascular disease in those with blood pressure within this range ( 20 ) . Major exclusion criteria were a body mass index less than 18.5 kg/mg2 or greater than 45.0 kg/m2 , use of antihypertensive drugs or other drugs that affect blood pressure , JNC VI risk category C ( target organ damage or diabetes ) , use of prescription weight loss medications , previous cardiovascular event , congestive heart failure , angina , cancer , and consumption of more than 21 alcoholic drinks per week . Trial Conduct Eligible participants were r and omly assigned , with equal probability , to 1 of 3 groups : an advice only comparison group ( advice only ) ; an intervention group that targeted established , guideline -recommended lifestyle recommendations ( established ) ( 2 ) ; or an intervention group targeting the established recommendations and adding the DASH dietary pattern ( established plus DASH ) ( 13 ) . Computer-generated treatment assignments were stratified by clinic and hypertension status and were assigned in blocks of varying sizes to provide balance over time . The actual assignments were administered by using a password-protected , Web-based application developed by the coordinating center and accessible only by authorized individuals . All clinic measurement staff were blinded to treatment assignment , and all intervention staff were blinded to clinic measurements . Hypertension was defined by using the JNC VI criteria for hypertension treatment : an average systolic blood pressure of 140 mm Hg , a diastolic blood pressure greater than 90 mm Hg , or use of antihypertensive medication . Normal blood pressure was defined as systolic blood pressure less than 120 mm Hg , diastolic blood pressure less than 80 mm Hg , and no use of antihypertensive medication ( 21 ) ( Figure ) . Intervention was provided by master 's degreelevel counselors ( dietitians and health educators trained in behavioral methods ) . The counselors were central ly trained before the start of the study , attended annual 3-day training sessions , and participated in monthly conference calls . Figure . Flow diagram of enrollment , measurements , and visit completion . Advice Only  Group Participants in the advice group  received advice to follow the National High Blood Pressure Education Program lifestyle recommendations for blood pressure control ( 2 ) . Lifestyle recommendations included reducing weight ( if overweight ) , following a reduced-sodium diet , engaging in regular moderate-intensity physical activity , and eating a heart-healthy diet , including the DASH diet . This advice was provided in two 30-minute individual sessions , 1 immediately after r and om assignment and 1 after the 6-month data collection visit . A PREMIER counselor review ed the guidelines with the participant and provided printed educational material s and information about community re sources . This intervention did not include advice to keep a food or exercise diary . Behavioral Interventions in the Established and Established plus DASH Groups Participant goals for the established and established plus DASH groups included weight loss of at least 6.8 kg ( 15 lb ) for those with a body mass index of 25 kg/m2 or greater , at least 180 minutes per week of moderate-intensity physical activity , no more than 100 mmol per day of dietary sodium , and alcohol consumption of no more than 30 mL ( 1 oz ) per day ( 2 drinks ) for men and 15 mL ( 0.5 ) oz per day ( 1 drink ) for women . Participants assigned to the established plus DASH group ( but not those in the established group ) also received counseling on the DASH diet , with goals for increased consumption of fruits and vegetables ( 9 to 12 servings/d ) and low-fat dairy products ( 2 to 3 servings/d ) and reduced consumption of saturated fat ( 7 % of energy ) and total fat ( 25 % of energy ) . The intervention format , contact pattern , and behavior change strategies for the established and established plus DASH groups were identical . During the first 6 months , participants in both behavioral intervention groups attended 14 group sessions and 4 individual sessions ; during months 7 to 18 , they attended monthly group sessions supplemented with 3 individual counseling sessions . Throughout the trial , participants in the established and established plus DASH groups ( but not those in the advice group ) kept food diaries , monitored dietary calorie and sodium intakes , and recorded minutes of physical activity . Self-monitoring was used to provide individualized feedback , reinforcement , problem solving , and support . Social support for initial behavior changes and maintenance of change was provided during the group sessions . More detailed descriptions of the behavorial intervention methods are available ( 22 ) . Measurements Blood pressure was assessed twice at each measurement , and systolic and diastolic blood pressures were calculated by using the mean of all available measurements ( 4 sets before r and om assignment , 3 sets at 6 and 18 months , and 1 set at 3 and 12 months ) . For 4 participants who were started on antihypertensive drug therapy between the 12- and 18-month visits , we obtained an official set of blood pressure measurements before initiation of therapy and used these as our 18-month blood pressure values for analysis . A similar procedure was used to obtain the 6-month blood pressure value for the 1 participant who began taking antihypertensive drugs between the 3- and 6-month visits . Two 24-hour dietary recalls , 1 obtained on a weekday and the other obtained on a weekend , were collected at baseline and at 6 and 18 months by telephone interview ( 23 ) . Intakes of nutrients and food groups were calculated by using the Nutrition Data System for Research , version NDS-R 1998 ( University of Minnesota , Minneapolis , Minnesota ) . Urinary excretion of sodium ( reflecting salt intake ) and potassium ( reflecting fruit and vegetable intake ) was obtained from 24-hour urinary collection s at baseline OBJECTIVE To examine the influence of the PREMIER study lifestyle interventions on dietary intakes and adherence to the Dietary Approaches to Stop Hypertension ( DASH ) dietary pattern and the Dietary Reference Intakes ( DRI ) . DESIGN An 18-month multicenter , r and omized controlled trial comparing two multicomponent lifestyle intervention programs to an advice only control group . SUBJECTS/ SETTING A total of 810 participants were recruited from local communities and r and omized into the study . Individuals were eligible if they were aged 25 years or older , had body mass index between 18.5 and 45.0 , not taking antihypertensive medication , and had prehypertension or stage 1 hypertension ( systolic blood pressure 120 to 159 mm Hg and diastolic blood pressure 80 to 95 mm Hg ) . INTERVENTION The two active intervention programs were a behavioral lifestyle intervention that implements established recommendations , and an established intervention plus the DASH dietary pattern . Both interventions consisted of intensive group and individual counseling sessions . The control group received a brief advice session after r and omization and again after 6 months of data collection . Dietary intakes were collected by two r and om 24-hour recalls at baseline , 6 months , and 18 months . MAIN OUTCOME MEASURES The primary outcome of the PREMIER study was change in systolic blood pressure at 6 months . The main outcomes examined here include dietary variables collected by 24-hour recall at each time point . STATISTICAL ANALYSES Nutrient intakes were calculated and compared among the time points and the three intervention groups using mixed models with repeated measures at 6 and 18 months . Proportion of participants who met or achieved the original DASH nutrient intake levels and the DRIs were calculated and compared among the three intervention groups . P<0.01 was considered statistically significant . RESULTS Participants in both the established intervention and established intervention plus DASH dietary pattern groups substantially reduced energy , total fat , saturated fat , and sodium intake and these reductions persisted throughout the study . Established intervention plus DASH dietary pattern group participants increased intakes of fruits , vegetables , dairy , and many vitamins and minerals ; these increases were significantly greater than that of the control and established intervention groups . A majority of established intervention plus DASH dietary pattern group participants achieved at least two thirds of the DRI recommendations for most nutrients at 6 months , despite their reduction in total energy intake . Some but relatively small recidivism occurred at 18 months . CONCLUSIONS Both the established intervention and established intervention plus DASH dietary pattern group intervention were effective in helping participants follow established recommendations to control blood pressure . The advice-only control group also made some behavior changes , mainly decreasing energy and sodium intake . Only the established intervention plus DASH dietary pattern group significantly increased intakes of DASH-specific food groups , including fruits , vegetables , and dairy products , and nutrients , including protein , fiber , calcium , potassium , and magnesium . Most of the increases did not reach the levels consumed in the original DASH feeding studies . Whereas the established intervention plus DASH dietary pattern group intervention provides a useful platform to achieve the DASH dietary pattern and current DRI recommendations , intervention enhancements , including a greater emphasis on nutrient-dense foods , would likely improve this intervention Background : Population s eating mainly vegetarian diets have lower blood pressure levels than those eating omnivorous diets . Epidemiologic findings suggest that eating fruits and vegetables lowers blood pressure OBJECTIVES To survey the frequency of use of indirect comparisons in systematic review s and evaluate the methods used in their analysis and interpretation . Also to identify alternative statistical approaches for the analysis of indirect comparisons , to assess the properties of different statistical methods used for performing indirect comparisons and to compare direct and indirect estimates of the same effects within review s. DATA SOURCES Electronic data bases . REVIEW METHODS The Data base of Abstract s of Review s of Effects ( DARE ) was search ed for systematic review s involving meta- analysis of r and omised controlled trials ( RCTs ) that reported both direct and indirect comparisons , or indirect comparisons alone . A systematic review of MEDLINE and other data bases was carried out to identify published methods for analysing indirect comparisons . Study design s were created using data from the International Stroke Trial . R and om sample s of patients receiving aspirin , heparin or placebo in 16 centres were used to create meta-analyses , with half of the trials comparing aspirin and placebo and half heparin and placebo . Methods for indirect comparisons were used to estimate the contrast between aspirin  and  heparin . The whole process was repeated 1000 times and the results were compared with direct comparisons and also theoretical results . Further detailed case studies comparing the results from both direct and indirect comparisons of the same effects were undertaken . RESULTS Of the review s identified through DARE , 31/327 ( 9.5 % ) included indirect comparisons . A further five review s including indirect comparisons were identified through electronic search ing . Few review s carried out a formal analysis and some based analysis on the naive addition of data from the treatment arms of interest . Few method ological papers were identified . Some valid approaches for aggregate data that could be applied using st and ard software were found : the adjusted indirect comparison , meta-regression and , for binary data only , multiple logistic regression ( fixed effect models only ) . Simulation studies showed that the naive method is liable to bias and also produces over-precise answers . Several methods provide correct answers if strong but unverifiable assumptions are fulfilled . Four times as many similarly sized trials are needed for the indirect approach to have the same power as directly r and omised comparisons . Detailed case studies comparing direct and indirect comparisons of the same effect show considerable statistical discrepancies , but the direction of such discrepancy is unpredictable . CONCLUSIONS Direct evidence from good- quality RCTs should be used wherever possible . Without this evidence , it may be necessary to look for indirect comparisons from RCTs . However , the results may be susceptible to bias . When making indirect comparisons within a systematic review , an adjusted indirect comparison method should ideally be used employing the r and om effects model . If both direct and indirect comparisons are possible within a review , it is recommended that these be done separately before considering whether to pool data . There is a need to evaluate methods for the analysis of indirect comparisons for continuous data and for empirical research into how different methods of indirect comparison perform in cases where there is a large treatment effect . Further study is needed into when it is appropriate to look at indirect comparisons and when to combine both direct and indirect comparisons . Research into how evidence from indirect comparisons compares to that from non-r and omised studies may also be warranted . Investigations using individual patient data from a meta- analysis of several RCTs using different protocol s and an evaluation of the impact of choosing different binary effect measures for the inverse variance method would also be useful Evidence for a beneficial effect of dietary nitrate , through the nitrate-nitrite-NO pathway , on measures of cardiovascular function in healthy individuals is accumulating . It is less clear whether increased dietary nitrate intake from green leafy vegetables would have similar beneficial vascular effects in those at increased risk of developing hypertension . Our aim was to assess the effects of short-term regular consumption of increased nitrate from green leafy vegetables on blood pressure and arterial stiffness in individuals with high-normal blood pressure . Thirty-eight men and women ages 30 - 70 years with systolic blood pressure 120 to 139 mm Hg were recruited to a r and omized controlled crossover trial . The effects of a 7-day high-nitrate diet intervention ( increased nitrate intake by at least 300 mg/day from green leafy vegetables ) were compared to a 7-day low-nitrate diet intervention . Outcome measures included pre- and postintervention salivary and plasma nitrate and nitrite concentrations ; ambulatory , home , and office blood pressure ; augmentation index ; and carotid-femoral pulse wave velocity . The high-nitrate diet intervention result ed in at least a fourfold increase in salivary and plasma nitrate and nitrite ( P<0.001 ) . Ambulatory , home , and office blood pressure and arterial stiffness were not different between the high-nitrate diet and the low-nitrate diet . Increasing dietary nitrate intake in those with high-normal blood pressure and at increased risk of hypertension may not be an effective short-term strategy to lower blood pressure OBJECTIVES To propose methods for mixed treatment comparisons ( MTC ) based on pooled summaries of the type produced in overviews of review s. STUDY DESIGN AND SETTING Overviews of review s ( umbrella review s ) summarize the results of multiple systematic review s into a single document . They report the summary estimates from the original pairwise meta-analyses and discuss them in narrative form , with the intention of identifying the most effective treatment . We present methods for MTC synthesis , tailored for use with overviews of review s. These generate a single internally consistent summary of all the relative treatment effects and assessment s of whether the summary is consistent with the data . These methods are applied to a published overview of treatments for childhood nocturnal enuresis . We apply the methods to both fixed-effect ( FE ) and r and om-effects ( RE ) meta-analyses of the original trials . RESULTS The summary relative risks based on FE meta-analyses , as originally published , were highly inconsistent . Those based on RE meta-analyses were consistent and could , given st and ard assumptions on comparability of treatment effects in meta- analysis , form a basis for coherent decision making . CONCLUSION Along with the summaries from systematic review s , MTC methods should be used in overviews to provide a single coherent analysis of all treatment comparisons and to check for evidence consistency High blood pressure increases the risks of stroke , dementia , and neurocognitive dysfunction . Although aerobic exercise and dietary modifications have been shown to reduce blood pressure , no r and omized trials have examined the effects of aerobic exercise combined with dietary modification on neurocognitive functioning in individuals with high blood pressure ( ie , prehypertension and stage 1 hypertension ) . As part of a larger investigation , 124 participants with elevated blood pressure ( systolic blood pressure 130 to 159 mm Hg or diastolic blood pressure 85 to 99 mm Hg ) who were sedentary and overweight or obese ( body mass index : 25 to 40 kg/m2 ) were r and omized to the Dietary Approaches to Stop Hypertension ( DASH ) diet alone , DASH combined with a behavioral weight management program including exercise and caloric restriction , or a usual diet control group . Participants completed a battery of neurocognitive tests of executive function-memory-learning and psychomotor speed at baseline and again after the 4-month intervention . Participants on the DASH diet combined with a behavioral weight management program exhibited greater improvements in executive function-memory-learning ( Cohen 's D=0.562 ; P=0.008 ) and psychomotor speed ( Cohen 's D=0.480 ; P=0.023 ) , and DASH diet alone participants exhibited better psychomotor speed ( Cohen 's D=0.440 ; P=0.036 ) compared with the usual diet control . Neurocognitive improvements appeared to be mediated by increased aerobic fitness and weight loss . Also , participants with greater intima-medial thickness and higher systolic blood pressure showed greater improvements in executive function-memory-learning in the group on the DASH diet combined with a behavioral weight management program . In conclusion , combining aerobic exercise with the DASH diet and caloric restriction improves neurocognitive function among sedentary and overweight/obese individuals with prehypertension and hypertension BACKGROUND Systematic review s may be compromised by selective inclusion and reporting of outcomes and analyses . Selective inclusion occurs when there are multiple effect estimates in a trial report that could be included in a particular meta- analysis ( e.g. from multiple measurement scales and time points ) and the choice of effect estimate to include in the meta- analysis is based on the results ( e.g. statistical significance , magnitude or direction of effect ) . Selective reporting occurs when the reporting of a subset of outcomes and analyses in the systematic review is based on the results ( e.g. a protocol -defined outcome is omitted from the published systematic review ) . OBJECTIVES To summarise the characteristics and synthesis e the results of empirical studies that have investigated the prevalence of selective inclusion or reporting in systematic review s of r and omised controlled trials ( RCTs ) , investigated the factors ( e.g. statistical significance or direction of effect ) associated with the prevalence and quantified the bias . SEARCH METHODS We search ed the Cochrane Methodology Register ( to July 2012 ) , Ovid MEDLINE , Ovid EMBASE , Ovid PsycINFO and ISI Web of Science ( each up to May 2013 ) , and the US Agency for Healthcare Research and Quality ( AHRQ ) Effective Healthcare Program 's Scientific Re source Center ( SRC ) Methods Library ( to June 2013 ) . We also search ed the abstract books of the 2011 and 2012 Cochrane Colloquia and the article alerts for method ological work in research synthesis published from 2009 to 2011 and compiled in Research Synthesis Methods . SELECTION CRITERIA We included both published and unpublished empirical studies that investigated the prevalence and factors associated with selective inclusion or reporting , or both , in systematic review s of RCTs of healthcare interventions . We included empirical studies assessing any type of selective inclusion or reporting , such as investigations of how frequently RCT outcome data is selectively included in systematic review s based on the results , outcomes and analyses are discrepant between protocol and published review or non-significant outcomes are partially reported in the full text or summary within systematic review s. DATA COLLECTION AND ANALYSIS Two review authors independently selected empirical studies for inclusion , extracted the data and performed a risk of bias assessment . A third review author resolved any disagreements about inclusion or exclusion of empirical studies , data extraction and risk of bias . We contacted authors of included studies for additional unpublished data . Primary outcomes included overall prevalence of selective inclusion or reporting , association between selective inclusion or reporting and the statistical significance of the effect estimate , and association between selective inclusion or reporting and the direction of the effect estimate . We combined prevalence estimates and risk ratios ( RRs ) using a r and om-effects meta- analysis model . MAIN RESULTS Seven studies met the inclusion criteria . No studies had investigated selective inclusion of results in systematic review s , or discrepancies in outcomes and analyses between systematic review registry entries and published systematic review s. Based on a meta- analysis of four studies ( including 485 Cochrane Review s ) , 38 % ( 95 % confidence interval ( CI ) 23 % to 54 % ) of systematic review s added , omitted , up grade d or down grade d at least one outcome between the protocol and published systematic review . The association between statistical significance and discrepant outcome reporting between protocol and published systematic review was uncertain . The meta-analytic estimate suggested an increased risk of adding or upgrading ( i.e. changing a secondary outcome to primary ) when the outcome was statistically significant , although the 95 % CI included no association and a decreased risk as plausible estimates ( RR 1.43 , 95 % CI 0.71 to 2.85 ; two studies , n = 552 meta-analyses ) . Also , the meta-analytic estimate suggested an increased risk of downgrading ( i.e. changing a primary outcome to secondary ) when the outcome was statistically significant , although the 95 % CI included no association and a decreased risk as plausible estimates ( RR 1.26 , 95 % CI 0.60 to 2.62 ; two studies , n = 484 meta-analyses ) . None of the included studies had investigated whether the association between statistical significance and adding , upgrading or downgrading of outcomes was modified by the type of comparison , direction of effect or type of outcome ; or whether there is an association between direction of the effect estimate and discrepant outcome reporting . Several secondary outcomes were reported in the included studies . Two studies found that reasons for discrepant outcome reporting were infrequently reported in published systematic review s ( 6 % in one study and 22 % in the other ) . One study ( including 62 Cochrane Review s ) found that 32 % ( 95 % CI 21 % to 45 % ) of systematic review s did not report all primary outcomes in the abstract . Another study ( including 64 Cochrane and 118 non-Cochrane review s ) found that statistically significant primary outcomes were more likely to be completely reported in the systematic review abstract than non-significant primary outcomes ( RR 2.66 , 95 % CI 1.81 to 3.90 ) . None of the studies included systematic review s published after 2009 when reporting st and ards for systematic review s ( Preferred Reporting Items for Systematic review s and Meta-Analyses ( PRISMA ) Statement , and Method ological Expectations of Cochrane Intervention Review s ( MECIR ) ) were disseminated , so the results might not be generalisable to more recent systematic review s. AUTHORS ' CONCLUSIONS Discrepant outcome reporting between the protocol and published systematic review is fairly common , although the association between statistical significance and discrepant outcome reporting is uncertain . Complete reporting of outcomes in systematic review abstract s is associated with statistical significance of the results for those outcomes . Systematic review outcomes and analysis plans should be specified prior to seeing the results of included studies to minimise post-hoc decisions that may be based on the observed results . Modifications that occur once the review has commenced , along with their justification , should be clearly reported . Effect estimates and CIs should be reported for all systematic review outcomes regardless of the results . The lack of research on selective inclusion of results in systematic review s needs to be addressed and studies that avoid the method ological weaknesses of existing research are also needed Dietary polyphenols , such as those from grape products , may exert beneficial effects on cardiovascular health , including anti-hypertensive effects . We investigated the effect of a specific grape seed extract ( GSE ) rich in low-molecular-weight polyphenolic compounds on ambulatory blood pressure ( ABP ) in untreated subjects with pre- and stage I hypertension . In addition , potential mechanisms that could underlie the hypothesised effect of GSE on blood pressure ( BP ) , and platelet aggregation , were explored . The study was design ed as a double-blind , placebo-controlled , r and omised , parallel-group intervention study including seventy healthy subjects with systolic BP between 120 and 159 mmHg . A 1-week run-in period was followed by an 8-week intervention period , during which subjects consumed capsules containing either 300 mg/d of GSE or a placebo ( microcrystalline cellulose ) . Before and after the intervention , daytime ABP readings , 24 h urine sample s and fasting and non-fasting blood sample s were taken . The mean baseline systolic BP was 135.8 ( SE 1.3 ) mmHg and diastolic BP was 81.5 ( SE 0.9 ) mmHg . BP values were modestly , but not significantly , affected by the polyphenol-rich GSE treatment v. placebo with an effect of - 3.0 mmHg for systolic BP ( 95 % CI - 6.5 , 0.5 ) and - 1.4 mmHg for diastolic BP ( 95 % CI - 3.5 , 0.6 ) . Vasoactive markers including endothelin-1 , NO metabolites and asymmetric dimethylarginine , plasma renin activity and platelet aggregation were not affected by the GSE intervention . Our findings show that consumption of polyphenol-rich GSE does not significantly lower ABP in untreated subjects with pre- and stage I hypertension AIMS To analyse the effect on systematic review s in diabetes interventions of including only trials that are indexed in medline , and to assess the impact of adding trials from other data bases and the grey literature . METHODS All systematic review s of diabetes interventions which included a meta- analysis of r and omized controlled trials , and were published since 1996 , were selected . The impact on the meta- analysis of including only those trials indexed in medline , and the effect of then adding trials from other sources , was assessed . Where possible this was measured quantitatively , by redoing the meta- analysis , otherwise a qualitative estimate was made . RESULTS Forty-four systematic review s met our inclusion criteria . There were 120 articles reporting trial data which were not indexed in medline . These came from 52 % of the review s. In 34 % of the review s , basing a meta- analysis on a search of only medline would miss trials that could affect the result . Sources of non- medline data which had the biggest effect on the meta-analyses were journal articles from central and embase ( mainly in Diabetes , Nutrition and Metabolism ) and unpublished data ( mainly from industry ) . The exceptions were journal articles on herbal medicine , mostly indexed in Chinese language data bases . CONCLUSIONS A search of only the medline data base is insufficient for systematic review s of diabetes , because in about 34 % of review s the missed trials could affect the results of the meta- analysis . It is recommended that central ( on the Cochrane Library ) also be search ed . Scanning meeting abstract s , and seeking unpublished data are also recommended if the intervention has only recently been introduced Background The ideal evidence to answer a question about the effectiveness of treatment is a systematic review . However , for many clinical questions a systematic review will not be available , or may not be up to date . One option could be to use the evidence from an individual trial to answer the question ? Methods We assessed how often ( a ) the estimated effect and ( b ) the p-value in the most precise single trial in a meta- analysis agreed with the whole meta- analysis . For a r and om sample of 200 completed Cochrane Review s ( January , 2005 ) we identified a primary outcome and extracted : the number of trials , the statistical weight of the most precise trial , the estimate and confidence interval for both the highest weighted trial and the meta- analysis overall . We calculated the p-value for the most precise trial and meta- analysis . Results Of 200 review s , only 132 provided a meta- analysis of 2 or more trials , with a further 35 effect estimates based on single trials . The average number of trials was 7.3 , with the most precise trial contributing , on average , 51 % of the statistical weight to the summary estimate from the whole meta- analysis . The estimates of effect from the most precise trial and the overall meta-analyses were highly correlated ( rank correlation of 0.90).There was an 81 % agreement in statistical conclusions . Results from the most precise trial were statistically significant in 60 of the 167 evaluable review s , with 55 of the corresponding systematic review s also being statistically significant . The five discrepant results were not strikingly different with respect to their estimates of effect , but showed considerable statistical heterogeneity between trials in these meta-analyses . However , among the 101 cases in which the most precise trial was not statistically significant , the corresponding meta-analyses yielded 31 statistically significant results . Conclusions Single most precise trials provided similar estimates of effects to those of the meta-analyses to which they contributed , and statistically significant results are generally in agreement . However , " negative " results were less reliable , as may be expected from single underpowered trials . For systematic review ers we suggest that : ( 1 ) key trial(s ) in a review deserve greater attention ( 2 ) systematic review ers should check agreement of the most precise trial and the meta analysis . For clinicians using trials we suggest that when a meta- analysis is not available , a focus on the most precise trial is reasonable provided it is adequately powered Data from 12 independently design ed and conducted r and omized trials of behavioral interventions for hypertension , consisting principally of variants of relaxation and biofeedback therapies , were aggregated to assess current progress of research in this area . Meta-analytical methods revealed a statistically significant decrease in diastolic blood pressure for nonmedicated patients at the end of intervention . No significant improvement was detected in medicated patients , but potential differential effectiveness of prescribed medications and differences in compliance among patients prohibits separation of changes due to behavioral treatments alone . The need to devise criteria for selection of patients , and to establish the most appropriate patient-treatment match is emphasized BACKGROUND Dietary nitrate , which is in green leafy vegetables and beetroot , decreases blood pressure through the enterosalivary nitrate-nitrite-nitric oxide pathway in healthy individuals . Whether similar effects would occur in individuals with treated hypertension and , therefore , at increased risk of cardiovascular disease is unclear . OBJECTIVE We assessed whether increased dietary nitrate intake by using beetroot juice for 1 wk lowers blood pressure in treated hypertensive men and women . DESIGN Participants ( n = 27 ) were recruited to a r and omized , placebo-controlled , double-blind crossover trial . The effect of 1-wk intake of nitrate-rich beetroot juice was compared with 1-wk intake of nitrate-depleted beetroot juice ( placebo ) . The primary outcome was blood pressure assessed by measuring home blood pressure during the intervention and 24-h ambulatory blood pressure on day 7 of the intervention . Other outcomes included nitrate metabolism assessed by measuring nitrate and nitrite in plasma , saliva , and urine . RESULTS Relative to the placebo , 1-wk intake of nitrate-rich beetroot juice result ed in a 3-fold increase in plasma nitrite and nitrate , a 7-fold increase in salivary nitrite , an 8-fold higher salivary nitrate , and a 4-fold increase in both urinary nitrite and nitrate ( P < 0.001 ) . However , no differences in home blood pressure and 24-h ambulatory blood pressure were observed with 1-wk intake of nitrate-rich beetroot juice in comparison with the placebo . CONCLUSION An increase in dietary nitrate intake may not be an effective short-term approach to further lower blood pressure in treated hypertensive subjects BACKGROUND Observational epidemiological studies have shown a positive association between hypertension and risk of incident dementia ; however , the effects of antihypertensive therapy on cognitive function in controlled trials have been conflicting , and meta-analyses of the trials have not provided clear evidence of whether antihypertensive treatment reduces dementia incidence . The Hypertension in the Very Elderly trial ( HYVET ) was design ed to assess the risks and benefits of treatment of hypertension in elderly patients and included an assessment of cognitive function . METHODS Patients with hypertension ( systolic pressure 160 - 200 mm Hg ; diastolic pressure < 110 mm Hg ) who were aged 80 years or older were enrolled in this double-blind , placebo-controlled trial . Participants were r and omly assigned to receive 1.5 mg slow release indapamide , with the option of 2 - 4 mg perindopril , or placebo . The target systolic blood pressure was 150 mm Hg ; the target diastolic blood pressure was 80 mm Hg . Participants had no clinical diagnosis of dementia at baseline , and cognitive function was assessed at baseline and annually with the mini-mental state examination ( MMSE ) . Possible cases of incident dementia ( a fall in the MMSE score to < 24 points or a drop of three points in 1 year ) were assessed by st and ard diagnostic criteria and expert review . The trial was stopped in 2007 at the second interim analysis after treatment result ed in a reduction in stroke and total mortality . Analysis was by intention to treat . The trial is registered with Clinical Trials.gov , number NCT00122811 . FINDINGS 3336 HYVET participants had at least one follow-up assessment ( mean 2.2 years ) and were included : 1687 participants were r and omly assigned to the treatment group and 1649 to the placebo group . Only five reports of adverse effects were attributed to the medication : three in the placebo group and two in the treatment group . The mean decrease in systolic blood pressure between the treatment and placebo groups at 2 years was systolic -15 mm Hg , p<0.0001 ; and diastolic -5.9 mm Hg , p<0.0001 . There were 263 incident cases of dementia . The rates of incident dementia were 38 per 1000 patient-years in the placebo group and 33 per 1000 patient-years in the treatment group . There was no significant difference between treatment and placebo groups ( hazard ratio [ HR ] 0.86 , 95 % CI 0.67 - 1.09 ) ; however , when these data were combined in a meta- analysis with other placebo-controlled trials of antihypertensive treatment , the combined risk ratio favoured treatment ( HR 0.87 , 0.76 - 1.00 , p=0.045 ) . INTERPRETATION Antihypertensive treatment  in elderly patients does not statistically reduce incidence of dementia . This negative finding might have been due to the short follow-up , owing to the early termination of the trial , or the modest effect of treatment . Nevertheless , the HYVET findings , when included in a meta- analysis , might support antihypertensive treatment to reduce incident dementia OBJECTIVES Determine whether self-efficacy independently predicted weight loss in a behavioral intervention and explore factors that influence the path between self-efficacy and weight change . DESIGN Secondary analysis of the PREMIER trial , a r and omized controlled trial testing effects of lifestyle interventions on blood pressure . SETTING Four academic medical centers . PARTICIPANTS PREMIER recruited adults ( n = 810 ) with pre-hypertension/stage 1 hypertension , not currently receiving medication . This analysis excluded participants in the control arm , result ing in n = 537 . INTERVENTIONS Participants were r and omly assigned to 1 of 3 groups : advice only , established lifestyle recommendations , or established lifestyle recommendations plus Dietary Approaches to Stop Hypertension dietary pattern . MAIN OUTCOME MEASURES Self-efficacy ( dietary self-efficacy [ DSE ] , exercise self-efficacy [ ESE ] ) , dietary intake , fitness . ANALYSIS Pearson correlations , 1-way analysis of variance , mediation analyses . RESULTS Despite an overall decrease in DSE/ESE , change in DSE/ESE significantly predicted weight change at 6 ( β = -.21 , P < .01 ; β = -.19 , P < .01 , respectively ) and 18 months ( β = -.19 , P < .01 ; β = -.35 , P < .01 ) . Change in percent calories from fat partially mediated the DSE/weight change relationship at 6 months . Change in fitness partially mediated the ESE/weight change relationship at 18 months . CONCLUSIONS AND IMPLICATION S Changes in DSE/ESE were not associated with behavior change as hypothesized . Additional research is needed to identify mediators between self-efficacy and adoption of behaviors that influence weight loss The Dietary Approaches to Stop Hypertension multicenter trial examined the impact of dietary patterns on blood pressure in 459 adults with blood pressure < 160 mm Hg systolic and 80 to 95 mm Hg diastolic . After a 3-week run-in period on a control diet low in fruits , vegetables , and dairy products , and with a fat content typical for Americans , participants were r and omized for 8 weeks to either the control diet , a diet rich in fruits and vegetables , or a combination diet that emphasized fruits , vegetables , and low-fat dairy products . Body weight and sodium intake were held constant , and physical activity did not change during the intervention . Baseline mean + /- st and ard deviation systolic and diastolic blood pressures were 131.3 + /- 10.8 mm Hg and 84.7 + /- 4.7 mm Hg , respectively . Relative to the control diet , the combination diet reduced blood pressure by 5.5 mm Hg and diastolic blood pressure by 3.0 mm Hg ( P < .001 ) . For those on the fruits and vegetables diet , blood pressure reductions relative to control were 2.8 mm Hg systolic ( P < .001 ) and 1.1 mm Hg diastolic ( P < .07 ) . In 133 participants with hypertension , the combination diet produced a net blood pressure reduction of 11.4 and 5.5 mm Hg systolic and diastolic , respectively ( P < .001 ) . In participants without hypertension ( n = 326 ) , the corresponding blood pressure reductions were 3.5 mm Hg systolic ( P < .001 ) and 2.1 mm Hg diastolic ( P < .003 ) . In other subgroup analyses , minorities showed relatively larger reductions in blood pressure than nonminorities ( P < .001 ) . We conclude that the dietary pattern reflected in the combination diet can substantially reduce blood pressure , and , accordingly , provides an additional lifestyle approach to preventing and treating hypertension 2011 ; 14 : 371–380 . 6 . Senn S , Gavini F , Magrez D , Scheen A. Issues in performing a network meta analysis . Statistical Methods in Medical Research 2013 ; 22 : 169–89 . 7 . Salanti G , Higgins JP , Ades A , Ioannidis JP . Evaluation of networks of r and omized trials . Statistical Methods in Medical Research 2008 ; 17 : 279– 301 . 8 . Song F , Clark A , Bachmann MO , Maas J. Simulation evaluation of statistical properties  of methods for indirect and mixed treatment comparisons . BMC Medical Research Methodology 2012 ; 12 : 1–14 . 9 . Jansen JP , Naci H. Is network meta- analysis as valid as st and ard pairwise meta- analysis ? It all depends on the distribution of effect modifers . BMC Medicine 2013 ; 11 : 1 . 10 . The Guidelines Manual . London : National Institute for Health and Clinical Excellence . 2012 . https://www . nice.org.uk/process/pmg6/chapter/6 review ing-the- evidence ( accessed 27/ 05/2017 ) . 11 . Kanters S , Ford N , Druyts E , et al. Use of network meta- analysis  in clinical guidelines . Bulletin of the World Health Organization 2016 ; 94 : 782–4 . 12 . Kiefer C , Sturtz S , Bender R. Indirect comparisons and network meta-analyses : estimation of effects in the absence of head-to-head trials . Deutsches € Arzteblatt International 2015 ; 112 : 803–8 . 13 . Imberger G , Gluud C , Boylan J , Wetterslev J. Systematic review s of anesthesiologic interventions reported as statistically significant : problems with power , precision , and type 1 error protection . Anesthesia and Analgesia 2015 ; 121 : 1611–22 . 14 . Afshari A , Wetterslev J , Smith AF . Can systematic review s with sparse data be trusted ? Anaesthesia 2017 ; 72 : 12–6 . 15 . Jakobsen JC , Wetterslev J , Lange T , Gluud C. Viewpoint : taking into account risks of r and om errors when analysing multiple outcomes in systematic review s. Cochrane Data base of Systematic Review s 2016 ; 3 : ED000111 . 16 . Jakobsen JC , Wetterslev J , Winkel P , Lange T , Gluud C. Thresholds for statistical and clinical significance in systematic review s with meta-analytic methods . BMC Medical Research Methodology 2014 ; 14 : 120 . 17 . Wetterslev J , Jakobsen JC , Gluud C. Trial Sequential Analysis in systematic review s with meta- analysis . BMC Medical Research Methodology 2017 ; 17 : 39 . 18 . Smith AF , Carlisle JC . Review s , systematic review s and Anaesthesia . Anaesthesia 2015 ; 70 : 644–70 . 19 . Cook TM , Kelly FE . The Difficult Airway Society 2015 guidelines and the sacred cows of routine airway management . Anaesthesia 2016 ; 71 : 466–7 . 20 . Schmitz S , Adams R , Walsh C. Incorporating data from various trial design s into a mixed treatment comparison model . Statistics in Medicine 2013 ; 32 : 2935–49 . 21 . Marshall SD , P and it JJ . Radical evolution : the 2015 Difficult Airway Society guidelines for managing unanticipated difficult or failed tracheal intubation . Anaesthesia 2016 ; 71 : 131–7 . 22 . Black AE , Flynn PE , Smith HL , Thomas ML , Wilkinson KA . Association of Pediatric Anaesthetists of Great Britain and Irel and . Development of a guideline for the management of the unanticipated difficult airway in pediatric practice . Pediatric Anaesthesia 2015 ; 25 : 346–62 . 23 . Hagberg CA , Gabel JC , Connis RT . Difficult Airway Society 2015 guidelines for the management of unanticipated difficult intubation in adults : not just another algorithm . British Journal of Anaesthesia 2015 ; 115 : 812–4 . 24 . Martin-Castro C , Montero A.  Flexible laryngeal mask as an alternative to reinforced tracheal tube for upper chest , head and neck oncoplastic surgery . European Journal of Anaesthesiology 2008 ; 25 : 261–6 . 25 . Maclennan A , Smith AF . An analysis of critical incidents relevant to paediatric anaesthesia reported to the UK National Reporting and Learning System , 2006 - 2008 . Pediatric Anesthesia 2011 ; 21 : 841–7 . 26 . P and it JJ , Popat MT , Cook TM , et al. The Difficult Airway Society ‘ ADEPT ’ Guidance on selecting airway devices : the basis of a strategy for equipment evaluation . Anaesthesia 2011 ; 66 : 726–37 Although epidemiologic data show a direct relation between dietary sodium intake and blood pressure at the population level ( 1 , 2 ) , some experts question the universality of the findings and oppose public health recommendations to decrease sodium intake in the general population ( 3 ) . Certainly , results from reports on the relationship between sodium and blood pressure among major subgroups vary considerably . Several studies suggest that African Americans and older adults have heightened salt sensitivity ( greater blood pressure response to sodium intake ) ( 4 - 6 ) . Some evidence also indicates increased salt sensitivity in women ( 7 ) , although other studies do not support this cl aim ( 4 , 5 ) . The association of sodium intake with cardiovascular morbidity and mortality varies by overweight status ( 8) , perhaps reflecting a differential effect of sodium on blood pressure in overweight persons . Finally , higher dietary intakes of potassium and calcium have been shown to blunt the pressor effects of dietary sodium ( 9 , 10 ) . Dietary factors other than sodium also directly affect blood pressure , and these effects also appear to vary across subgroups . In the Dietary Approaches to Stop Hypertension ( DASH ) Trial , for example , a diet that had reduced total and saturated fat and was rich in fruits , vegetables , and low-fat dairy foods ( the DASH diet ) substantially decreased blood pressure compared with a more typical U.S. diet , in the absence of weight change and at sodium intakes approximating current U.S. consumption ( 11 , 12 ) . These effects persisted across all subgroups and were especially pronounced among hypertensive persons , African Americans , and persons who did not drink alcohol ( 13 ) . The DASH-Sodium Trial examined the effects of reduced sodium intake in the context of the DASH diet and a more typical U.S. diet ( 14 ) . In that study , highly significant decreases in blood pressure were observed with decreased sodium intake in participants following either diet , and the DASH diet decreased blood pressure at sodium intakes well below the current U.S. average . These results were observed overall and in subgroups defined by ethnicity , sex , and hypertension status ( 15 ) . We report on more detailed subgroup analyses from the DASH-Sodium Trial , including results for subgroups defined by age , obesity , waist circumference , alcohol intake , and baseline sodium intake . We also report the results of multivariate analyses that demonstrate how these effects vary across subgroups defined jointly by age , ethnicity , sex , and hypertension status . Methods Study Design The DASH-Sodium Trial was a multicenter , r and omized feeding trial comparing the effects on blood pressure of three levels of sodium intake and two dietary patterns . The 412 participants were 22 years of age or older and had systolic blood pressures of 120 to 159 mm Hg and diastolic blood pressures of 80 to 95 mm Hg ( 15 ) . The three levels of sodium intake ( lower , intermediate , and higher ) varied according to energy intake in a ratio of 1:2:3 ; target intakes were 50 , 100 , and 150 mmol/d , respectively , for a 2100-kcal diet . The dietary patterns were a control diet , typical of what many Americans eat , and the DASH diet , which emphasizes fruits , vegetables , and low-fat dairy foods ; includes whole grains , poultry , fish , and nuts ; and is reduced in fats , red meat , sweets , and sugar-containing beverages ( 11 , 14 ) . Participants were recruited in four separate feeding cohorts and were r and omly assigned to one of the two dietary patterns by using a parallel-group design . They then ate their assigned diet for three consecutive 30-day intervention feeding periods , during which sodium intake varied among the three levels by a r and omly assigned sequence ( Figure ) . Participants ate the control diet at the higher sodium intake during a 2-week run-in period . During the three intervention periods , participants received all their food in the context of the study and were asked not to eat any non study food . Individual energy intake was adjusted to keep body weight stable . Figure . Design of the Dietary Approaches to Stop Hypertension (DASH)-Sodium Trial . Exclusion criteria were heart disease , renal insufficiency , poorly controlled hyperlipidemia or diabetes mellitus , diabetes requiring insulin , special dietary requirements , intake of more than 14 alcoholic drinks/wk , or use of antihypertensive drugs or other medications that would affect blood pressure or nutrient metabolism . The study was approved by the human subjects committees of the clinical centers and coordinating center , and participants gave informed consent . Measurement Protocol Trained staff measured blood pressure at each of three screening visits , on 2 days during the run-in period , and on 5 of the last 9 days of each intervention feeding period . Interim blood pressures were assessed once during each of the first 3 weeks of each intervention feeding period . During screening and the last week of each intervention feeding period , a 24-hour urine collection was obtained . Height and weight were measured , and body mass index was calculated . Baseline physical activity was measured by using a 7-day physical activity recall interview ( 16 ) . Information on education level , income , alcohol consumption , and family history was obtained by using a question naire . Baseline blood pressure was defined as the average of the five preintervention blood pressures . End-of-feeding blood pressures were defined as the average of the five blood pressures at the end of each 30-day intervention feeding period . If no end-of-feeding blood pressure values were available ( 49 of 1236 possible cases ) , interim ( n = 9 ) or screening ( n = 40 ) blood pressures were used to impute end-of-feeding blood pressures . Definitions of Subgroups Ethnicity was categorized as African American versus other ( primarily non-Hispanic white ) . Participants were considered hypertensive if their untreated baseline systolic blood pressure was 140 mm Hg or greater and their diastolic blood pressure was 90 mm Hg or greater . ( Use of antihypertensive agents was an exclusion criterion [ 17 ] . ) Obesity was defined as body mass index of 30 kg/m2 or greater , and high-risk waist circumference was defined as greater than 102 cm in men and greater than 88 cm in women ( 18 ) . Age , physical activity , baseline alcohol intake , baseline 24-hour urinary sodium level , and family income were dichotomized at the approximate median . Level of education was dichotomized as high school or less versus more than high school . Statistical Analysis The data were analyzed on an intention-to-treat basis . Given the differential effects of sodium on blood pressure observed in previous analyses among participants eating the DASH diet versus the control diet ( 15 ) and because power for subgroup analyses is more limited than for overall analysis , we focused our comparisons on the maximum contrasts ( higher versus lower sodium intake with the control diet , DASH diet versus control diet at the higher sodium intake , and the combined effect of DASH diet and lower sodium intake versus control diet and higher sodium intake ) . We used generalized estimating equations ( 19 ) to fit linear models that predicted baseline and end-of-feeding blood pressures as a function of diet ( DASH vs. control ) , sodium level , and subgroup indicators . Different ways of modeling the dietsodium effects and their interactions with the subgroup indicators were used to test specific hypotheses . In particular , two-way interactions of the various dietsodium effects with ethnicity , sex , hypertension status , and age were analyzed to determine the incremental effect on blood pressure in each of these subgroups while controlling for the main and incremental effects of the other subgroups . This model allowed us to estimate various diet-sodium contrasts for each of the 16 subgroups defined by hypertension status , ethnicity , sex , and age . A second set of models examined subgroup variables in a bivariate manner and did not assume simple additivity of subgroup effects . Finally , unadjusted subgroup analyses included main effects and interactions for a single subgroup indicator . All analyses were performed by using the xtgee procedure in Stata software , version 5 ( Stata Corp. , College Station , Texas ) ( 20 ) and included adjustment for baseline blood pressure , site , feeding cohort , and carryover effects . An exchangeable covariance matrix was assumed for the repeated measurements for each participant . Unless otherwise stated , a P value less than 0.05 was significant , and all confidence intervals are 95 % confidence intervals . Because subgroup analyses were planned to interpret and eluci date the overall study results , they are not adjusted for multiple comparisons . Results Of the 412 participants who underwent r and omization , 390 ( 95 % ) completed the 12-week intervention feeding period . Adherence to the study diets seemed excellent , and body weight remained stable over time ( 15 ) . Table 1 shows baseline characteristics of the 412 participants .  Mean urinary sodium excretion at screening was 155 mmol/d , a value higher than that found while participants ate higher-sodium diets ( 142 mmol/d ) . Table 1 . Characteristics of Study Sample Several key subgroups were highly interrelated . Women made up 70 % of African-American participants but only 39 % of non-African-American participants . Women were more likely to be hypertensive than were men . The percentage of both men and women with hypertension increased sharply with age among non-African-American participants ( 21 % of those 45 years of age vs. 47 % of those > 45 years of age ) but was equally high among older and younger African Americans ( 43 % of those 45 years of age vs. 45 % of those > 45 years of age ) . These correlations highlight the potential for confounding in our results and , hence , the importance of the multivariate-adjusted analyses . Effects of the DASH Diet Table 2 shows the effect on systolic blood pressure of the DASH diet compared with the control diet Background Dietary Approaches to Stop Hypertension ( DASH ) has been shown to successfully reduce systolic ( SBP ) and diastolic blood pressure ( DBP ) when evaluated in clinical ly controlled environments but there is a lack of information regarding the efficacy of the original DASH diet when it is applied in a free-living environment . Purpose To provide descriptive data as to the changes in blood pressure individuals could expect to achieve when following the DASH diet in a free-living environment for 4-weeks with no additional behavioral modifications . Methods Twenty , pre- and stage 1 hypertensive participants were r and omly split into 2 groups ; DASH ( males N = 5 , females N = 5 , age = 38.5 ± 10.8 ) and control ( males N = 7 , females N = 3 , age = 38.1 ± 11.1 ) . The DASH group was instructed on how to follow the DASH diet on their own for 4-weeks while the control group continued their normal diet  . SBP , DBP , body weight , 3-day food diaries and physical activity recall question naire data were collected pre and post intervention using a traditional person-to-person instructional technique . Results Two-way ANOVA demonstrated that there was a significant group ( DASH , control ) by time ( pre , post ) interaction for SBP ( P = 0.003 ) and no significant effects for DBP . The interaction was due to a significant reduction ( P < 0.001 ) in SBP in the DASH group ( pre : 141.3 ± 11.3 mmHg vs. post : 130.7 ± 9.1 mmHg ) over the course of the intervention with no change in SBP in the control group ( pre : 133.5 ± 6.6 mmHg vs. post : 131.9 ± 8.9 mmHg ) . Pearson 's correlation analyses revealed that changes in potential moderators of blood pressure including body weight , BMI , sodium intake and total kilocalories were each not associated with changes in SBP ( r ≤ 0.14 , P ≥ 0.5 ) or DBP ( r < 0.10 , P ≥ 0.6 ) pre- to post-treatment . Chi-square demonstrated no significant differences in the number of participants per group ( n = 4 DASH , n = 1 control ) who indicated increasing physical activity during the intervention . Conclusion DASH diet followed in a free-living environment significantly reduced SBP but not DBP . However , the changes in SBP and DBP were very similar to those noted in controlled clinical feeding evaluations of the DASH diet . Presently , none of the potential moderators of blood pressure that were assessed were independently associated with the observed changes in blood pressure which may be due to our small sample size or the possibility that it is the combined change in multiple factors that lead to reductions in blood pressure when following the DASH diet Networks of investigators have begun sharing best practice s , tools and methods for analysis of associations between genetic variation and common diseases . A Network of Investigator Networks has been set up to drive the process , sponsored by the Human Genome Epidemiology Network . A workshop is planned to develop consensus guidelines for reporting results of genetic association studies . Published literature data bases will be integrated , and unpublished data , including ' negative ' studies , will be captured by online journals and through investigator networks . Systematic review s will be exp and ed to include more meta-analyses of individual-level data and prospect i ve meta-analyses . Field synopses will offer regularly up date d overviews Background Although cardiorespiratory fitness ( CRF ) in childhood and adolescence may be linked to future cardiovascular health , there is currently limited evidence for a longitudinal association . Objectives To provide a systematic review on the prospect i ve association between CRF in childhood and adolescence and cardiovascular disease ( CVD ) risk factors at least 2 years later . Methods Using a systematic search of Medline , Embase , and SPORTD iscus , relevant articles were identified by the following criteria : generally healthy children and adolescents between 3 and 18 years of age with CRF assessed at baseline , and a follow-up period of ≥ 2 years . The outcome measures were CVD risk factors . We appraised quality of the included articles with STROBE and QUIPS checklists . Results After screening 7524 titles and abstract s , we included 38 articles , assessing 44,169 children and adolescents followed up for a median of 6 years . Eleven articles were of high quality . There was considerable heterogeneity in methodology , measurement of CRF , and outcomes , which hampered meta- analysis . In approximately half of the included articles higher CRF in childhood and adolescence was associated with lower body mass index ( BMI ) , waist circumference , body fatness and lower prevalence of metabolic syndrome in later life . No associations between CRF in childhood and adolescence and future waist-to-hip ratio , blood pressure , lipid profile , and glucose homeostasis were observed . Conclusion Although about half of the included articles reported inverse associations between CRF in childhood and adolescence and future BMI , body fatness , and metabolic syndrome , evidence for other CVD risk factors was unconvincing . Many articles did not account for important confounding factors such as adiposity . Recommendations for future research include st and ardizing the measurement of CRF , i.e. by reporting VO2max , using st and ardized outcome assessment s , and performing individual patient data meta-analyses
For most comparisons , the credibility of evidence was rated very low to moderate , with the exception for the DASH vs. the low-fat dietary approach for which the quality of evidence was rated high .
Conclusion : The present network meta- analysis suggests that the DASH dietary approach might be the most effective dietary measure to reduce blood pressure among hypertensive and pre-hypertensive patients based on high quality evidence
ABSTRACT Background : Pairwise meta-analyses have shown beneficial effects of individual dietary approaches on blood pressure but their comparative effects have not been established .
Objective : Therefore we performed a systematic review of different dietary intervention trials and estimated the aggregate blood pressure effects through network meta- analysis including hypertensive and pre-hypertensive patients .