Pao-Hwa Lin

Effects on Blood Pressure of Reduced Dietary Sodium and the Dietary Approaches to Stop Hypertension (DASH) Diet

Background The effect of dietary composition on blood pressure is a subject of public health importance. We studied the effect of different levels of dietary sodium, in conjunction with the Dietary Approaches to Stop Hypertension (DASH) diet, which is rich in vegetables, fruits, and low-fat dairy products, in persons with and in those without hypertension. Methods A total of 412 participants were randomly assigned to eat either a control diet typical of intake in the United States or the DASH diet. Within the assigned diet, participants ate foods with high, intermediate, and low levels of sodium for 30 consecutive days each, in random order. Results Reducing the sodium intake from the high to the intermediate level reduced the systolic blood pressure by 2.1 mm Hg (P<0.001) during the control diet and by 1.3 mm Hg (P=0.03) during the DASH diet. Reducing the sodium intake from the intermediate to the low level caused additional reductions of 4.6 mm Hg during the control diet (P<0.001) and 1.7 mm Hg during t...

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 randomly 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. Implications 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 randomized 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 reviewed 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 clinically 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 randomly 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 masters degreelevel counselors (dietitians and health educators trained in behavioral methods). The counselors were centrally 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 random assignment and 1 after the 6-month data collection visit. A PREMIER counselor reviewed the guidelines with the participant and provided printed educational materials and information about community resources. 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 random 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 collections at baseline a

Effects of the DASH diet alone and in combination with exercise and weight loss on blood pressure and cardiovascular biomarkers in men and women with high blood pressure: the ENCORE study.

BACKGROUND Although the DASH (Dietary Approaches to Stop Hypertension) diet has been shown to lower blood pressure (BP) in short-term feeding studies, it has not been shown to lower BP among free-living individuals, nor has it been shown to alter cardiovascular biomarkers of risk. OBJECTIVE To compare the DASH diet alone or combined with a weight management program with usual diet controls among participants with prehypertension or stage 1 hypertension (systolic BP, 130-159 mm Hg; or diastolic BP, 85-99 mm Hg). DESIGN AND SETTING Randomized, controlled trial in a tertiary care medical center with assessments at baseline and 4 months. Enrollment began October 29, 2003, and ended July 28, 2008. PARTICIPANTS Overweight or obese, unmedicated outpatients with high BP (N = 144). INTERVENTIONS Usual diet controls, DASH diet alone, and DASH diet plus weight management. OUTCOME MEASURES The main outcome measure is BP measured in the clinic and by ambulatory BP monitoring. Secondary outcomes included pulse wave velocity, flow-mediated dilation of the brachial artery, baroreflex sensitivity, and left ventricular mass. RESULTS Clinic-measured BP was reduced by 16.1/9.9 mm Hg (DASH plus weight management); 11.2/7.5 mm (DASH alone); and 3.4/3.8 mm (usual diet controls) (P < .001). A similar pattern was observed for ambulatory BP (P < .05). Greater improvement was noted for DASH plus weight management compared with DASH alone for pulse wave velocity, baroreflex sensitivity, and left ventricular mass (all P < .05). CONCLUSION For overweight or obese persons with above-normal BP, the addition of exercise and weight loss to the DASH diet resulted in even larger BP reductions, greater improvements in vascular and autonomic function, and reduced left ventricular mass. CLINICAL TRIAL REGISTRATION clinicaltrials.gov Identifier: NCT00571844.

Weight Loss During the Intensive Intervention Phase of the Weight-Loss Maintenance Trial

BACKGROUND To improve methods for long-term weight management, the Weight Loss Maintenance (WLM) trial, a four-center randomized trial, was conducted to compare alternative strategies for maintaining weight loss over a 30-month period. This paper describes methods and results for the initial 6-month weight-loss program (Phase I). METHODS Eligible adults were aged > or =25, overweight or obese (BMI=25-45 kg/m2), and on medications for hypertension and/or dyslipidemia. Anthropomorphic, demographic, and psychosocial measures were collected at baseline and 6 months. Participants (n=1685) attended 20 weekly group sessions to encourage calorie restriction, moderate-intensity physical activity, and the DASH (dietary approaches to stop hypertension) dietary pattern. Weight-loss predictors with missing data were replaced by multiple imputation. RESULTS Participants were 44% African American and 67% women; 79% were obese (BMI> or =30), 87% were taking anti-hypertensive medications, and 38% were taking antidyslipidemia medications. Participants attended an average of 72% of 20 group sessions. They self-reported 117 minutes of moderate-intensity physical activity per week, kept 3.7 daily food records per week, and consumed 2.9 servings of fruits and vegetables per day. The Phase-I follow-up rate was 92%. Mean (SD) weight change was -5.8 kg (4.4), and 69% lost at least 4 kg. All race-gender subgroups lost substantial weight: African-American men (-5.4 kg +/- 7.7); African-American women (-4.1 kg +/- 2.9); non-African-American men (-8.5 kg +/- 12.9); and non-African-American women (-5.8 kg +/- 6.1). Behavioral measures (e.g., diet records and physical activity) accounted for most of the weight-loss variation, although the association between behavioral measures and weight loss differed by race and gender groups. CONCLUSIONS The WLM behavioral intervention successfully achieved clinically significant short-term weight loss in a diverse population of high-risk patients.

Descriptive Characteristics of the Dietary Patterns Used in the Dietary Approaches to Stop Hypertension Trial

The Dietary Approaches to Stop Hypertension trial was a randomized, multicenter, controlled feeding study to compare the effect on blood pressure of 3 dietary patterns: control, fruits and vegetables, and combination diets. The patterns differed in selected nutrients hypothesized to alter blood pressure. This article examines the food-group structure and nutrient composition of the study diets and reports participant nutrient consumption during intervention. Participants consumed the control dietary pattern during a 3-week run-in period. They were then randomized either to continue on the control diet or to change to the fruits and vegetables or the combination diet for 8 weeks. Sodium intake and body weight were constant during the entire feeding period. Analysis of variance models compared the nutrient content of the 3 diets. Targeting a few nutrients thought to influence blood pressure resulted in diets that were profoundly different in their food-group and nutrient composition. The control and fruits and vegetables diets contained more oils, table fats, salad dressings, and red meats and were higher in saturated fat, total fat, and cholesterol than was the combination diet. The fruits and vegetables and combination diets contained relatively more servings of fruits, juices, vegetables, and nuts/seeds, and were higher in magnesium, potassium, and fiber than was the control diet. Both the fruits and vegetables and combination diets were low in sweets and sugar-containing drinks. The combination diet contained a greater variety of fruits, and its high calcium content was obtained by increasing low-fat dairy products. In addition, the distinct food grouping pattern across the 3 diets resulted in substantial differences in the levels of vitamins A, C, E, folate, B-6, and zinc.

Reducing Consumption of Sugar-Sweetened Beverages Is Associated With Reduced Blood Pressure A Prospective Study Among United States Adults

Background— Increased consumption of sugar-sweetened beverages (SSBs) has been associated with an elevated risk of obesity, metabolic syndrome, and type II diabetes mellitus. However, the effects of SSB consumption on blood pressure (BP) are uncertain. The objective of this study was to determine the relationship between changes in SSB consumption and changes in BP among adults. Methods and Results— This was a prospective analysis of 810 adults who participated in the PREMIER Study (an 18-month behavioral intervention trial). BP and dietary intake (by two 24-hour recalls) were measured at baseline and at 6 and 18 months. Mixed-effects models were applied to estimate the changes in BP in responding to changes in SSB consumption. At baseline, mean SSB intake was 0.9±1.0 servings per day (10.5±11.9 fl oz/d), and mean systolic BP/diastolic BP was 134.9±9.6/84.8±4.2 mm Hg. After potential confounders were controlled for, a reduction in SSB of 1 serving per day was associated with a 1.8-mm Hg (95% confidence interval, 1.2 to 2.4) reduction in systolic BP and 1.1-mm Hg (95% confidence interval, 0.7 to 1.4) reduction in diastolic BP over 18 months. After additional adjustment for weight change over the same period, a reduction in SSB intake was still significantly associated with reductions in systolic and diastolic BPs (P<0.05). Reduced intake of sugars was also significantly associated with reduced BP. No association was found for diet beverage consumption or caffeine intake and BP. These findings suggest that sugars may be the nutrients that contribute to the observed association between SSB and BP. Conclusions— Reduced consumption of SSB and sugars was significantly associated with reduced BP. Reducing SSB and sugar consumption may be an important dietary strategy to lower BP. Clinical Trial Registration— URL: http://clinicaltrials.gov. Unique identifier: NCT00000616.

The effect of dietary patterns on blood pressure control in hypertensive patients: results from the Dietary Approaches to Stop Hypertension (DASH) trial.

To determine the impact of dietary patterns on the control of hypertension we studied the subgroup of 133 participants with systolic blood pressure (BP) of 140 to 159 mm Hg and/or diastolic BP of 90 to 95 mm Hg enrolled in the Dietary Approaches to Stop Hypertension (DASH) study. Participants were fed a control diet for a 3-week period and were then randomized to receive for 8 weeks either the control diet; a diet rich in fruits and vegetables, but otherwise similar to control; or a combination diet rich in fruits, vegetables, and low-fat dairy products, including whole grains, fish, poultry, and nuts, and reduced in fats, red meats, sweets, and sugar-containing beverages. Sodium intake and body weight were held constant throughout the study. The combination diet significantly reduced systolic BP (-11.4 mm Hg, P < .001) and diastolic BP (-5.5 mm Hg, P < .001). The fruits-and-vegetables diet also significantly reduced systolic BP (-7.2 mm Hg, P < .001) and diastolic BP (-2.8 mm Hg, P = .013). The combination diet produced significantly greater BP effects (P < .05) than the fruits-and-vegetables diet. Blood pressure changes were evident within 2 weeks of starting the intervention feeding. After the 8-week intervention period, 70% of participants eating the combination diet had a normal BP (systolic BP < 140 and diastolic BP < 90 mm Hg) compared with 45% on the fruits-and-vegetables diet and 23% on the control diet. In patients with hypertension, the DASH combination diet effectively lowers BP and may be useful in achieving control of Stage 1 hypertension.

Reduction in consumption of sugar-sweetened beverages is associated with weight loss: the PREMIER trial

BACKGROUND Consumption of liquid calories from beverages has increased in parallel with the obesity epidemic in the US population, but their causal relation remains unclear. OBJECTIVE The objective of this study was to examine how changes in beverage consumption affect weight change among adults. DESIGN This was a prospective study of 810 adults participating in the PREMIER trial, an 18-mo randomized, controlled, behavioral intervention trial. Measurements (weight, height, and 24-h dietary recall) were made at baseline, 6 mo, and 18 mo. RESULTS Baseline mean intake of liquid calories was 356 kcal/d (19% of total energy intake). After potential confounders and intervention assignment were controlled for, a reduction in liquid calorie intake of 100 kcal/d was associated with a weight loss of 0.25 kg (95% CI: 0.11, 0.39; P < 0.001) at 6 mo and of 0.24 kg (95% CI: 0.06, 0.41; P = 0.008) at 18 mo. A reduction in liquid calorie intake had a stronger effect than did a reduction in solid calorie intake on weight loss. Of the individual beverages, only intake of sugar-sweetened beverages (SSBs) was significantly associated with weight change. A reduction in SSB intake of 1 serving/d was associated with a weight loss of 0.49 kg (95% CI: 0.11, 0.82; P = 0.006) at 6 mo and of 0.65 kg (95% CI: 0.22, 1.09; P = 0.003) at 18 mo. CONCLUSIONS These data support recommendations to limit liquid calorie intake among adults and to reduce SSB consumption as a means to accomplish weight loss or avoid excess weight gain. This trial was registered at clinicaltrials.gov as NCT00000616.

Dietary Approaches to Stop Hypertension: Rationale, Design, and Methods

Epidemiologic studies across societies have shown consistent differences in blood pressure that appear to be related to diet. Vegetarian diets are consistently associated with reduced blood pressure in observational and interventional studies, but clinical trials of individual nutrient supplements have had an inconsistent pattern of results. Dietary Approaches to Stop Hypertension (DASH) was a multicenter, randomized feeding study, designed to compare the impact on blood pressure of 3 dietary patterns. DASH was designed as a test of eating patterns rather than of individual nutrients in an effort to identify practical, palatable dietary approaches that might have a meaningful impact on reducing morbidity and mortality related to blood pressure in the general population. The objectives of this article are to present the scientific rationale for this trial, review the methods used, and discuss important design considerations and implications.

Premier: a clinical trial of comprehensive lifestyle modification for blood pressure control: rationale, design and baseline characteristics

PURPOSE To describe PREMIER, a randomized trial to determine the effects of multi-component lifestyle interventions on blood pressure (BP). METHODS Participants with above optimal BP through stage 1 hypertension were randomized to: 1) a behavioral lifestyle (BLS) intervention that implements established recommendations, 2) a BLS intervention that implements established recommendations plus the DASH diet, or 3) an advice only standard of care group. The two BLS interventions consist of group and individual counseling sessions for 18 months. The primary outcome is systolic BP at 6 months. Additional outcomes include diastolic BP and homocysteine at 6 months; systolic and diastolic BP at 18 months; fasting lipids, glucose and insulin at 6 and 18 months; and effects in subgroup. CONCLUSION Results from the PREMIER trial will provide scientific rationale for implementing multi-component behavioral lifestyle intervention programs to control BP and prevent CVD.