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 .
Effects of Comprehensive Lifestyle Modification on Diet, Weight, Physical Fitness, and Blood Pressure Control: 18-Month Results of a Randomized Trial
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
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 .