Comparison of weight-loss diets with different compositions of fat, protein, and carbohydrates.

BACKGROUND: The possible advantage for weight loss of a diet that emphasizes protein, fat, or carbohydrates has not been established, and there are few studies that extend beyond 1 year. METHODS: We randomly assigned 811 overweight adults to one of four diets; the targeted percentages of energy derived from fat, protein, and carbohydrates in the four diets were 20, 15, and 65%; 20, 25, and 55%; 40, 15, and 45%; and 40, 25, and 35%. The diets consisted of similar foods and met guidelines for cardiovascular health. The participants were offered group and individual instructional sessions for 2 years. The primary outcome was the change in body weight after 2 years in two-by-two factorial comparisons of low fat versus high fat and average protein versus high protein and in the comparison of highest and lowest carbohydrate content. RESULTS: At 6 months, participants assigned to each diet had lost an average of 6 kg, which represented 7% of their initial weight; they began to regain weight after 12 months. By 2 years, weight loss remained similar in those who were assigned to a diet with 15% protein and those assigned to a diet with 25% protein (3.0 and 3.6 kg, respectively); in those assigned to a diet with 20% fat and those assigned to a diet with 40% fat (3.3 kg for both groups); and in those assigned to a diet with 65% carbohydrates and those assigned to a diet with 35% carbohydrates (2.9 and 3.4 kg, respectively) (P>0.20 for all comparisons). Among the 80% of participants who completed the trial, the average weight loss was 4 kg; 14 to 15% of the participants had a reduction of at least 10% of their initial body weight. Satiety, hunger, satisfaction with the diet, and attendance at group sessions were similar for all diets; attendance was strongly associated with weight loss (0.2 kg per session attended). The diets improved lipid-related risk factors and fasting insulin levels. CONCLUSIONS: Reduced-calorie diets result in clinically meaningful weight loss regardless of which macronutrients they emphasize. (ClinicalTrials.gov number, NCT00072995.)

Prevalence and incidence of hypertension in adolescent girls.

OBJECTIVE: To estimate the prevalence and incidence of hypertension and prehypertension and associated factors in adolescent girls. STUDY DESIGN: A total of 2368 girls (49% Caucasian, 51% African-American) aged 9 or 10 years enrolled in the National Heart, Lung, and Blood Institute Growth and Health Study had blood pressure, height, and weight measured at annual visits through age 18 to 19 years. Prevalence and incidence of hypertension and prehypertension were calculated. RESULTS: On the basis of 2 visits, hypertension prevalence was approximately 1% to 2% in African-American girls and 0.5% in Caucasian girls. Incidence in 8 years was 5.0% and 2.1%, respectively. Obese girls had higher prevalence (approximately 6-fold higher) and incidence (approximately 2- to 3-fold higher) compared with girls of normal weight. Similar patterns were found for prehypertension, except that prehypertension occurred more in older girls than younger girls. Dietary factors (lower intake of fiber, potassium, magnesium, and calcium, and higher intake of caffeine and calories) were each associated with hypertension incidence (all P<.05). In multivariate analysis, higher body mass index (P<.001) and lower potassium intake (P=.023) were independently associated with incidence of hypertension. CONCLUSIONS: Hypertension occurred early in childhood and was related to obesity and other modifiable lifestyle factors. Clinicians should monitor blood pressure during childhood and provide focused diet and physical activity guidance to minimize the development of hypertension.

Population-based prevention of obesity: the need for comprehensive promotion of healthful eating, physical activity, and energy balance: a scientific statement from American Heart Association Council on Epidemiology and Prevention, Interdisciplinary Committee for Prevention (formerly the expert panel on population and prevention science).

Obesity is a major influence on the development and course of cardiovascular diseases and affects physical and social functioning and quality of life. The importance of effective interventions to reduce obesity and related health risks has increased in recent decades because the number of adults and children who are obese has reached epidemic proportions. To prevent the development of overweight and obesity throughout the life course, population-based strategies that improve social and physical environmental contexts for healthful eating and physical activity are essential. Population-based approaches to obesity prevention are complementary to clinical preventive strategies and also to treatment programs for those who are already obese. This American Heart Association scientific statement aims: 1) to raise awareness of the importance of undertaking population-based initiatives specifically geared to the prevention of excess weight gain in adults and children; 2) to describe considerations for undertaking obesity prevention overall and in key risk subgroups; 3) to differentiate environmental and policy approaches to obesity prevention from those used in clinical prevention and obesity treatment; 4) to identify potential targets of environmental and policy change using an ecological model that includes multiple layers of influences on eating and physical activity across multiple societal sectors; and 5) to highlight the spectrum of potentially relevant interventions and the nature of evidence needed to inform population-based approaches. The evidence-based experience for population-wide approaches to obesity prevention is highlighted.

Memphis Girls health Enrichment Multi-site Studies (GEMS): Phase 2: design and baseline.

Obesity prevalence is increasing in the U.S., especially among children and minority populations. This report describes the design and baseline data of the ongoing Girls health Enrichment Multi-site Studies (GEMS) trial (Memphis site), which is testing the efficacy of a 2-year family-based intervention to reduce excessive increase in body mass index (BMI). This randomized, controlled trial conducted at community centers in Memphis, Tennessee requires major measurements at baseline and at 12 and 24 months post-randomization. The participants are healthy African-American girls and one parent/caregiver of each girl. Participating girls are of ages 8-10 years, with BMI>or=25th percentile of the CDC 2000 growth charts or with one overweight or obese parent/caregiver (BMI>or=25 kg/m(2)). The active intervention is designed to prevent excessive weight gain by promoting healthy eating habits and increasing physical activity. An alternative intervention (comparison group) promotes general self-esteem and social efficacy. The main outcome measure is the difference between the two treatment groups in the change in BMI at 2 years. Three hundred and three girls have been randomly assigned to receive the test intervention (n=153) or the alternative intervention (n=150). The two groups do not differ in baseline characteristics. At the time of enrollment, the mean age was 9 years, the mean BMI was 22 kg/m(2) (mean BMI percentile=77 th), and 41% were overweight (BMI>/=95th percentile using CDC 2000 growth charts). Participants' intake of fruits and vegetables (1.3 serving/day) and fats (36% kcal), and their participation in moderate-to-vigorous physical activity (20 min/day), did not meet national recommendations. The GEMS obesity prevention intervention targets improved diet and increased physical activity to reduce excessive weight gain in healthy African-American girls of ages 8-10.

Stanford GEMS phase 2 obesity prevention trial for low-income African-American girls: design and sample baseline characteristics.

OBJECTIVE: African-American girls and women are at high risk of obesity and its associated morbidities. Few studies have tested obesity prevention strategies specifically designed for African-American girls. This report describes the design and baseline findings of the Stanford GEMS (Girls health Enrichment Multi-site Studies) trial to test the effect of a two-year community- and family-based intervention to reduce weight gain in low-income, pre-adolescent African-American girls. DESIGN: Randomized controlled trial with measurements scheduled in girls' homes at baseline, 6, 12, 18 and 24 month post-randomization. SETTING: Low-income areas of Oakland, CA. PARTICIPANTS: Eight, nine and ten year old African-American girls and their parents/caregivers. INTERVENTIONS: Girls are randomized to a culturally-tailored after-school dance program and a home/family-based intervention to reduce screen media use versus an information-based community health education Active-Placebo Comparison intervention. Interventions last for 2 years for each participant. MAIN OUTCOME MEASURE: Change in body mass index over the two-year study. RESULTS: Recruitment and enrollment successfully produced a predominately low-socioeconomic status sample. Two-hundred sixty one (261) families were randomized. One girl per family is randomly chosen for the analysis sample. Randomization produced comparable experimental groups with only a few statistically significant differences. The sample had a mean body mass index (BMI) at the 74 th percentile on the 2000 CDC BMI reference, and one-third of the analysis sample had a BMI at the 95th percentile or above. Average fasting total cholesterol and LDL cholesterol were above NCEP thresholds for borderline high classifications. Girls averaged low levels of moderate to vigorous physical activity, more than 3 h per day of screen media use, and diets high in energy from fat. CONCLUSIONS: The Stanford GEMS trial is testing the benefits of culturally-tailored after-school dance and screen-time reduction interventions for obesity prevention in low-income, pre-adolescent African-American girls.

Childhood overweight and cardiovascular disease risk factors: the National Heart, Lung, and Blood Institute Growth and Health Study.

OBJECTIVE: To estimate the prevalence and incidence of overweight in African-American and Caucasian girls, and to examine associations between adolescent overweight and cardiovascular disease (CVD) risk factors. STUDY DESIGN: In the National Heart, Lung and Blood Institute Growth and Health Study (NGHS), annual measurements were obtained from girls followed longitudinally between age 9 or 10 and 18 years; self-reported measures were obtained at age 21 to 23 years. A total of 1166 Caucasian girls and 1213 African-American girls participated in the study. Childhood overweight as defined by the Centers for Disease Control and Prevention (CDC) was the independent variable of primary interest. Measured outcomes included blood pressure and lipid levels. RESULTS: Rates of overweight increased through adolescence from 7% to 10% in the Caucasian girls and from 17% to 24% in the African-American girls. The incidence of overweight was greater at age 9 to 12 than in later adolescence. Girls who were overweight during childhood were 11 to 30 times more likely to be obese in young adulthood. Overweight was significantly associated with increased percent body fat, sum of skinfolds and waist circumference measurements, and unhealthful systolic and diastolic blood pressure, high-density lipoprotein cholesterol, and triglyceride levels. CONCLUSION: A relationship between CVD risk factors and CDC-defined overweight is present at age 9.

Acceptability of sodium-reduced research diets, including the Dietary Approaches To Stop Hypertension diet, among adults with prehypertension and stage 1 hypertension.

OBJECTIVE: Examine the acceptability of sodium-reduced research diets. DESIGN: Randomized crossover trial of three sodium levels for 30 days each among participants randomly assigned to one of two dietary patterns. PARTICIPANTS/SETTING: Three hundred fifty-four adults with prehypertension or stage 1 hypertension who were participants in the Dietary Approaches to Stop Hypertension (DASH-Sodium) outpatient feeding trial. INTERVENTION: Participants received their assigned diet (control or DASH, rich in fruits, vegetables, and low-fat dairy products), each at three levels of sodium (higher, intermediate, and lower) corresponding to 3,500, 2,300, and 1,200 mg/day (150, 100, and 50 mmol/day) per 2,100 kcal. MAIN OUTCOME MEASURES: Nine-item questionnaire on liking and willingness to continue the assigned diet and its level of saltiness using a nine-point scale, ranging from one to nine. STATISTICAL ANALYSES PERFORMED: Generalized estimating equations to test participant ratings as a function of sodium level and diet while adjusting for site, feeding cohort, carryover effects, and ratings during run-in. RESULTS: Overall, participants rated the saltiness of the intermediate level sodium as most acceptable (DASH group: 5.5 for intermediate vs 4.5 and 4.4 for higher and lower sodium; control group: 5.7 for intermediate vs 4.9 and 4.7 for higher and lower sodium) and rated liking and willing to continue the DASH diet more than the control diet by about one point (ratings range from 5.6 to 6.6 for DASH diet and 5.2 to 6.1 for control diet). Small race differences were observed in sodium and diet acceptability. CONCLUSIONS: Both the intermediate and lower sodium levels of each diet are at least as acceptable as the higher sodium level in persons with or at risk for hypertension.

Effects of comprehensive lifestyle modification on diet, weight, physical fitness, and blood pressure control: 18-month results of a randomized trial.

BACKGROUND: The main 6-month results from the PREMIER trial showed that comprehensive behavioral intervention programs improve lifestyle behaviors and lower blood pressure. OBJECTIVE: To compare the 18-month effects of 2 multicomponent behavioral interventions versus advice only on hypertension status, lifestyle changes, and blood pressure. DESIGN: Multicenter, 3-arm, randomized trial conducted from January 2000 through November 2002. SETTING: 4 clinical centers and a coordinating center. PATIENTS: 810 adult volunteers with prehypertension or stage 1 hypertension (systolic blood pressure, 120 to 159 mm Hg; diastolic blood pressure, 80 to 95 mm Hg). INTERVENTIONS: A multicomponent behavioral intervention that implemented long-established recommendations ("established"); a multicomponent behavioral intervention that implemented the established recommendations plus the Dietary Approaches to Stop Hypertension (DASH) diet ("established plus DASH"); and advice only. MEASUREMENTS: Lifestyle variables and blood pressure status. Follow-up for blood pressure measurement at 18 months was 94%. RESULTS: Compared with advice only, both behavioral interventions statistically significantly reduced weight, fat intake, and sodium intake. The established plus DASH intervention also statistically significantly increased fruit, vegetable, dairy, fiber, and mineral intakes. Relative to the advice only group, the odds ratios for hypertension at 18 months were 0.83 (95% CI, 0.67 to 1.04) for the established group and 0.77 (CI, 0.62 to 0.97) for the established plus DASH group. Although reductions in absolute blood pressure at 18 months were greater for participants in the established and the established plus DASH groups than for the advice only group, the differences were not statistically significant. LIMITATIONS: The exclusion criteria and the volunteer nature of this cohort may limit generalizability. Although blood pressure is a well-accepted risk factor for cardiovascular disease, the authors were not able to assess intervention effects on clinical cardiovascular events in this limited time and with this sample size. CONCLUSIONS: Over 18 months, persons with prehypertension and stage 1 hypertension can sustain multiple lifestyle modifications that improve control of blood pressure and could reduce the risk for chronic disease.

Effects of individual components of multiple behavior changes: the PREMIER trial.

OBJECTIVES: To assess contributions of individual lifestyle changes on systolic blood pressure (SBP) changes. METHODS: We examined associations between lifestyle behavior changes and SBP after 6 and 18 months in 782 PREMIER trial participants. RESULTS: In multivariate models omitting weight, predicted SBP reductions ranged from (1)/2 to 1(1)/2 mm Hg for reduced urinary sodium, improved fitness, and adherence to the DASH diet (except sodium at 18 months). With weight included, only fitness change additionally predicted SBP at 18 months. CONCLUSIONS: Several lifestyle behavior changes are important for BP lowering, but are difficult to detect when weight is included in multivariate models.

Relation between the changes in physical activity and body-mass index during adolescence: a multicentre longitudinal study.

BACKGROUND: The role of physical activity in preventing obesity during adolescence remains unknown. We examined changes in activity in relation to changes in body-mass index (BMI) and adiposity in a cohort of 1152 black and 1135 white girls from the USA, who were followed up prospectively from ages 9 or 10 to 18 or 19 years. METHODS: BMI and sum of skinfold thickness were assessed annually, whereas habitual activity was assessed at years 1 (baseline), 3, 5, and 7-10. Each girls' overall activity status was categorised as active, moderately active, or inactive. Longitudinal regression models examined associations between changes in activity and in overall activity status with changes in BMI and in sum of skinfold thickness. FINDINGS: Each decline in activity of 10 metabolic equivalent [MET]-times per week was associated with an increase in BMI of 0.14 kg/m2 (SE 0.03) and in sum of skinfold thickness of 0.62 mm (0.17) for black girls, and of 0.09 kg/m2 (0.02) and 0.63 mm (0.13) for white girls. At ages 18 or 19 years, BMI differences between active and inactive girls were 2.98 kg/m2 (p<0.0001) for black girls and 2.10 kg/m2 (p<0.0001) for white girls. Similar results were apparent for sum of skinfold thickness. For moderately active girls, changes in BMI and sum of skinfold thickness were about midway between those for active and inactive girls. INTERPRETATION: Changes in activity levels of US girls during adolescence significantly affected changes in BMI and adiposity. Thus, preventing the steep decline in activity during adolescence is an important method to reduce obesity.

Fast-food intake and diet quality in black and white girls: the National Heart, Lung, and Blood Institute Growth and Health Study.

OBJECTIVE: To examine trends in fast-food consumption and its relationship to calorie, fat, and sodium intake in black and white adolescent girls. DESIGN: A longitudinal multicenter cohort study of the development of obesity and cardiovascular risk factors in black and white female adolescents. Data collection occurred annually using a validated 3-day food record and a food-patterns questionnaire. SUBJECTS AND SETTINGS: A biracial and socioeconomically diverse group of 2379 black and white girls recruited from 3 centers. MAIN OUTCOME MEASURE: Three-day food records and a food-patterns questionnaire were examined for intake of fast food and its association with nutrient intake. We compared patterns of exposure to fast food and its impact on intake of calories, fat, and sodium. RESULTS: Fast-food intake was positively associated with intake of energy and sodium as well as total fat and saturated fat as a percentage of calories. Fast-food intake increased with increasing age in both races. With increasing consumption of fast food, energy intake increased with an adjusted mean of 1837 kcal for the low fast-food frequency group vs 1966 kcal for the highest fast-food frequency group (P<.05). Total fat in the low fast-food frequency group was 34.3% as opposed to 35.8% in the highest fast-food frequency group (P<.05). Saturated fat went from 12.5% to 13% and sodium increased from 3085 mg to 3236 mg in the lowest vs the highest fast-food frequency group (P<.001). CONCLUSIONS: Dietary intake of fast food is a determinant of diet quality in adolescent girls. Efforts to reduce fast-food consumption may be useful in improving diet and risk for future cardiovascular disease.

Imprecise control of energy intake: absence of a reduction in food intake following overfeeding in young adults.

The objective was to examine the extent to which overfeeding reduces spontaneous food intake in humans. Twelve normal-weight adults participated in the three stage study. During the 14 day baseline period and 21 day recovery period, food intake was consumed ad libitum, beyond a minimum 5 MJ (1200 kcal) basal diet. During the 13 day period of overfeeding, each subject consumed 35% more energy than they consumed at baseline. Overfeeding resulted in a weight gain of 2.3+/-0.37 kg, (p<0.0001), approximately half the weight gain was determined to be fat (1.2+/-0.19 kg, p<0.0001) by underwater densitometry. Following overfeeding, mean daily caloric intake was not significantly suppressed returning immediately to baseline values. Despite normal energy intake, participants lost 1.3+/-0.24 kg of body weight (p<0.0001), of which 0.75+/-0.15 kg (p<0.0001) was fat. These results indicated that (1) the physiological control of eating behavior in humans is not the major mechanism responsible for the recovery of body weight following a period of overfeeding and (2) an increase in energy expenditure of 1.28 MJ (307 kcal)/day or about 14% was required to account for the weight loss following overfeeding.

Breakfast consumption by African-American and white adolescent girls correlates positively with calcium and fiber intake and negatively with body mass index.

OBJECTIVE: To describe age- and race-related differences in breakfast consumption and to examine the association of breakfast intake with dietary calcium and fiber and body mass index (BMI). DESIGN: Data from the National Heart, Lung, and Blood Institute Growth and Health Study, a 9-year, longitudinal biracial cohort study with annual 3-day food records. SUBJECTS/SETTING: The National Heart, Lung, and Blood Institute Growth and Health Study recruited 2,379 girls (1,166 white and 1,213 African American), aged 9 or 10 years at baseline for an observational study. Retention rates were very high at visits two through four (96%, 94%, and 91%), but declined to a low of 82% at visit seven, and increased to 89% at visit 10. MAIN OUTCOME MEASURES: Frequency of breakfast consumption, dietary calcium and fiber, and BMI. STATISTICAL ANALYSES: Generalized estimation equations methodology was used to examine differences in the frequency of breakfast eating by age and race. Generalized estimation equations analyses were also conducted to test whether breakfast consumption was predictive of intake of dietary calcium and fiber, and BMI, adjusting for potentially confounding effects of site, age, race, parental education, physical activity, and total energy intake. RESULTS: Frequency of breakfast eating declined with age, white girls reported more frequent breakfast consumption than African-American girls, and the racial difference decreased with increasing age. Days eating breakfast were associated with higher calcium and fiber intake in all models, regardless of adjustment variables. Days eating breakfast were predictive of lower BMI in models that adjusted for basic demographics (ie, site, age, and race), but the independent effect of breakfast was no longer significant after parental education, energy intake, and physical activity were added to the model. CONCLUSIONS: Dietetics professionals need to promote the importance of consuming breakfast to all children and adolescents, especially African-American girls.

Effects of protein, monounsaturated fat, and carbohydrate intake on blood pressure and serum lipids: results of the OmniHeart randomized trial.

CONTEXT: Reduced intake of saturated fat is widely recommended for prevention of cardiovascular disease. The type of macronutrient that should replace saturated fat remains uncertain. OBJECTIVE: To compare the effects of 3 healthful diets, each with reduced saturated fat intake, on blood pressure and serum lipids. DESIGN, SETTING, AND PARTICIPANTS: Randomized, 3-period, crossover feeding study (April 2003 to June 2005) conducted in Baltimore, Md, and Boston, Mass. Participants were 164 adults with prehypertension or stage 1 hypertension. Each feeding period lasted 6 weeks and body weight was kept constant. INTERVENTIONS: A diet rich in carbohydrates; a diet rich in protein, about half from plant sources; and a diet rich in unsaturated fat, predominantly monounsaturated fat. MAIN OUTCOME MEASURES: Systolic blood pressure and low-density lipoprotein cholesterol. RESULTS: Blood pressure, low-density lipoprotein cholesterol, and estimated coronary heart disease risk were lower on each diet compared with baseline. Compared with the carbohydrate diet, the protein diet further decreased mean systolic blood pressure by 1.4 mm Hg (P = .002) and by 3.5 mm Hg (P = .006) among those with hypertension and decreased low-density lipoprotein cholesterol by 3.3 mg/dL (0.09 mmol/L; P = .01), high-density lipoprotein cholesterol by 1.3 mg/dL (0.03 mmol/L; P = .02), and triglycerides by 15.7 mg/dL (0.18 mmol/L; P<.001). Compared with the carbohydrate diet, the unsaturated fat diet decreased systolic blood pressure by 1.3 mm Hg (P = .005) and by 2.9 mm Hg among those with hypertension (P = .02), had no significant effect on low-density lipoprotein cholesterol, increased high-density lipoprotein cholesterol by 1.1 mg/dL (0.03 mmol/L; P = .03), and lowered triglycerides by 9.6 mg/dL (0.11 mmol/L; P = .02). Compared with the carbohydrate diet, estimated 10-year coronary heart disease risk was lower and similar on the protein and unsaturated fat diets. CONCLUSION: In the setting of a healthful diet, partial substitution of carbohydrate with either protein or monounsaturated fat can further lower blood pressure, improve lipid levels, and reduce estimated cardiovascular risk. Clinical Trials Registration ClinicalTrials.gov Identifier: NCT00051350.

Estimation of energy requirements in a controlled feeding trial.

BACKGROUND: Estimating energy requirements is a frequent task in clinical studies. OBJECTIVE: We examined weight patterns of participants enrolled in a clinical trial and evaluated factors that may affect weight stabilization. The Harris-Benedict equation and the FAO/WHO equation, used in conjunction with physical activity levels estimated with the 7-d Physical Activity Recall, were compared for estimating energy expenditure. DESIGN: This was a multicenter, randomized controlled feeding trial with participants of the Dietary Approaches to Stop Hypertension Trial. For 11 wk, the amount of food participants received was adjusted to maintain their body weights as close to their initial weights as possible. Change-point regression techniques were used to identify weight-stable periods. Factors related to achieving weight stabilization were examined with logistic regression. RESULTS: A stable weight was achieved by 86% of the 448 participants during the run-in period and by 78% during the intervention period. Energy intake averaged 11 +/- 2.4 MJ/d (2628 +/- 578 kcal/d), with most participants (n = 270) requiring 9-13 MJ/d (2100-3100 kcal/d). The difference between predicted and observed intakes was highest at high estimated energy intakes, mainly because of high and probably incorrect estimates of the activity factor. Participants with lower energy intakes tended to need less adjustment of their energy intakes to maintain a stable weight than did participants with higher energy intakes. CONCLUSIONS: Weight stabilization is not affected by diet composition, sex, race, age, or baseline weight. Either the Harris-Benedict equation or the FAO/WHO equation can be used to estimate energy needs. Activity factors > 1.7 often lead to overestimation of energy needs.

A further subgroup analysis of the effects of the DASH diet and three dietary sodium levels on blood pressure: results of the DASH-Sodium Trial.

This study presents an extensive analysis of the effects on blood pressure (BP) of changes in sodium intake over a wide array of subgroups, including joint subgroups defined by age and hypertension status, race or ethnicity and hypertension status, and gender and race or ethnicity. Participants were given 3 levels of sodium (50, 100, and 150 mmol/2,100 kcal) for 30 days while consuming the Dietary Approaches to Stop Hypertension (DASH) diet (rich in fruits, vegetables, and low-fat dairy) or a more typical American diet. Within each diet and subgroup, there was a general pattern such that the lower the sodium level, the greater the mean reduction in BP. Sodium reduction from 100 to 50 mmol/2,100 kcal generally had twice the effect on BP as reduction from 150 to 100 mmol/2,100 kcal. Age had a strong and graded influence on the effect of sodium within the typical and DASH diets, respectively: -4.8 and -1.0 mm Hg systolic for 23 to 41 years, -5.9 and -1.8 mm Hg for 42 to 47 years, -7.5 and -4.3 mm Hg for 48 to 54 years, and -8.1 and -6.0 mm Hg for 55 to 76 years. The influence of age on the effect of sodium reduction was particularly strong in nonhypertensive patients: -3.7 mm Hg systolic for <45 years and -7.0 mm Hg for >45 years with the typical diet and -0.7 and -2.8 mm Hg with the DASH diet. Reduced sodium intake and the DASH diet should be advocated for the prevention and treatment of high BP, particularly because the benefits to BP strengthen as subjects enter middle age, when the rate of cardiovascular disease increases sharply.

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.

Macronutrient intake of black and white adolescent girls over 10 years: the NHLBI Growth and Health Study.

OBJECTIVE: To compare age-related changes in macronutrient and cholesterol intake between black and white girls, compare intakes with National Cholesterol Education Program (NCEP) recommendations, and examine sociodemographic associations with macronutrient intake. DESIGN: Cohort study with 3-day food records collected over 10 years. SUBJECTS: 2,379 girls, 1,166 white and 1,213 black, age 9 to 10 years at baseline, recruited from three geographic locations. Statistical Analysis Longitudinal generalized estimating equation (GEE) regression models examined the relationships of age, ethnicity, and sociodemographic factors with macronutrient and cholesterol intake and with percentage of girls meeting NCEP recommendations. RESULTS: Total and saturated fat intakes decreased with age, more in white girls than black girls, from 35.1% and 13.6% kcal at age 9 to 29.3% and 10.4% at age 19 for white girls and from 36.5% and 13.4% kcal at age 9 to 35.1% and 11.7% kcal at age 19 for black girls. Dietary cholesterol decreased with age, but decreased more in white girls than black girls (range 95 to 119 mg/1,000 kcal for white girls and 119 to 132 mg/1,000 kcal for black girls). Depending on age, 7% to 51% of white girls and 8% to 26% of black girls met NCEP recommendations for total fat (

Validity and reliability of activity measures in African-American girls for GEMS.

PURPOSE: To determine the reliability and validity of physical activity monitors and self-report instruments suitable for young African-American girls. METHODS: A validation study was conducted by the Girls health Enrichment Multi-site Studies (GEMS) research team to compare an accelerometer with a pedometer and two self-report instruments for assessing physical activity in African-American girls, age 8-9 yr. Girls (N= 68) attended two clinic visits spaced 4 d apart. Each girl wore a MTI/CSA accelerometer (used as the criterion standard for validity) and a pedometer simultaneously for four consecutive days. Girls completed on two occasions a 24-h physical activity checklist of yesterday and usual activities, including sedentary activities (GEMS Activity Questionnaire, GAQ), and a 3-d computerized self-report instrument (Activitygram). RESULTS: Girls were (mean +/- SD) 9.0 +/- 0.6 yr old and had a body mass index of 19.4 kg x m. Reliability measured by intraclass correlations (ICC) and Pearson correlation coefficients (r) were calculated for the MTI/CSA (ICC = 0.37, P< 0.0001), pedometer (ICC = 0.08, = 0.094), Activitygram (ICC = 0.24) (P = 0.005), and GAQ for physical (r = 0.80, P< 0.0001) and sedentary (r = 0.3-0.5, P< 0.005) activities. Significant Pearson correlations between the MTI/CSA and the other instruments, as a measure of validity, were observed for the 4-d average pedometer score (r = 0.47, P< 0.0001), 3-d average Activitygram score (r = 0.37, P= 0.002), and the average of the two yesterday and two usual GAQ activity scores for a subset of 18 physical activities questions (r = 0.27, = 0.03; and r = 0.29,P = 0.02, respectively). The MTI/CSA was uncorrelated with single day scores from the three other instruments. CONCLUSION: The reliability of the instruments tested was acceptable, except the pedometer. Validity correlations were significant when more than one day was used. Self-report instruments need further development for improved reliability and validity.

Girls health Enrichment Multi-site Studies (GEMS): new approaches to obesity prevention among young African-American girls.

The Girls health Enrichment Multi-site Studies (GEMS) is an obesity prevention research program sponsored by the National Heart, Lung, and Blood Institute (NHLBI), targeting young African-American girls. Expert groups have suggested that the high prevalence of obesity in African-American women could be a contributing factor to their excess morbidity and mortality from cardiovascular disease compared to women from other ethnic groups. To address the issue of obesity and its origins in African-American women, the NHLBI Growth and Health Study (NGHS) was initiated to investigate factors related to the development of obesity and associated cardiovascular disease risk factors in a cohort of young African-American and White girls, aged 9 and 10 years. Findings from NGHS, and the realization that obesity had become a major public health problem, subsequently led to a 2-phase, 7-year collaborative obesity prevention research program, the Girls health Enrichment Multi-site Studies (GEMS). Initiated in 1999, Phase 1 of GEMS was conducted collaboratively among 4 participating field centers, a coordinating center, and the NHLBI project office to conduct formative assessment research and to pilot test, over a 12-week period, interventions that might be effective in reducing the rate of weight gain in African-American girls, aged 8-10 years. Over a 2-year period, Phase 2 of GEMS will test the interventions that appear most promising in preventing excessive weight gain in young African-American girls. The experiences of the GEMS pilot studies will help guide future intervention research for obesity prevention beginning in childhood. This report describes the background and rationale for the GEMS initiative. This journal supplement describes the experiences of the GEMS Phase 1 program.