Weight loss intervention in phase 1 of the Trials of Hypertension Prevention. The TOHP Collaborative Research Group

Changes in aortic diameter induced by weight loss: The HELENA trial- whole-body MR imaging in a dietary intervention trial

Obesity-related metabolic disorders such as hypertension, hyperlipidemia and chronic inflammation have been associated with aortic dilatation and resulting in aortic aneurysms in many cases. Whether weight loss may reduce the risk of aortic dilatation is not clear. In this study, the diameter of the descending thoracic aorta, infrarenal abdominal aorta and aortic bifurcation of 144 overweight or obese non-smoking adults were measured by MR-imaging, at baseline, and 12 and 50 weeks after weight loss by calorie restriction. Changes in aortic diameter, anthropometric measures and body composition and metabolic markers were evaluated using linear mixed models. The association of the aortic diameters with the aforementioned clinical parameters was analyzed using Spearman`s correlation. Weight loss was associated with a reduction in the thoracic and abdominal aortic diameters 12 weeks after weight loss (predicted relative differences for Quartile 4: 2.5% ± 0.5 and -2.2% ± 0.8, p < 0.031; respectively). Furthermore, there was a nominal reduction in aortic diameters during the 50-weeks follow-up period. Aortic diameters were positively associated with weight, visceral adipose tissue, glucose, HbA1c and with both systolic and diastolic blood pressure. Weight loss induced by calorie restriction may reduce aortic diameters. Future studies are needed to investigate, whether the reduction of aortic diameters via calorie restriction may help to prevent aortic aneurysms.

Non-pharmacologic treatment for obesity

Background: The prevalence of obesity has been rapidly increasing in the Korean population. Obesity is a well-known risk factor for various chronic diseases, including diabetes mellitus, hypertension, dyslipidemia, atherosclerosis, chronic kidney disease, degenerative arthritis, and autoimmune diseases. It also increases the risks of different malignancies, gall bladder disease, and pancreatitis.Current Concepts: Lifestyle intervention assisted by frequent behavioral therapy is crucial despite the modest amount of weight loss achieved. Energy intake restriction combined with increased physical activity can not only facilitate weight loss but also improve metabolic health. Furthermore, this combination can help maintain weight reduction during and after lifestyle interventions. Energy intake restriction with a daily deficit of 500–1,000 kcal and physical activity including aerobic exercise for 150 minutes or more per week and resistance training 2–4 times a week are generally recommended for obesity management.Discussion and Conclusion: Comprehensive lifestyle intervention should be individualized and supported by a multidisciplinary team. A long-term behavioral intervention is necessary for success in obesity treatment.

Microvessel Density: Integrating Sex-Based Differences and Elevated Cardiovascular Risks in Metabolic Syndrome

Metabolic syndrome (MetS) is a complex pathological state consisting of metabolic risk factors such as hypertension, insulin resistance, and obesity. The interconnectivity of cellular pathways within various biological systems suggests that each individual component of MetS may share common pathological sources. Additionally, MetS is closely associated with vasculopathy, including a reduction in microvessel density (MVD) (rarefaction) and elevated risk for various cardiovascular diseases. Microvascular impairments may contribute to perfusion-demand mismatch, where local metabolic needs are insufficiently met due to the lack of nutrient and oxygen supply, thus creating pathological positive-feedback loops and furthering the progression of disease. Sexual dimorphism is evident in these underlying cellular mechanisms, which places males and females at different levels of risk for cardiovascular disease and acute ischemic events. Estrogen exhibits protective effects on the endothelium of pre-menopausal women, while androgens may be antagonistic to cardiovascular health. This review examines MetS and its influences on MVD, as well as sex differences relating to the components of MetS and cardiovascular risk profiles. Finally, translational relevance and interventions are discussed in the context of these sex-based differences.

Prehypertension: Underlying pathology and therapeutic options

Prehypertension (PHTN) is a global major health risk that subjects individuals to double the risk of cardiovascular disease (CVD) independent of progression to overt hypertension. Its prevalence rate varies considerably from country to country ranging between 21.9% and 52%. Many hypotheses are proposed to explain the underlying pathophysiology of PHTN. The most notable of these implicate the renin-angiotensin system (RAS) and vascular endothelium. However, other processes that involve reactive oxygen species, the inflammatory cytokines, prostglandins and C-reactive protein as well as the autonomic and central nervous systems are also suggested. Drugs affecting RAS have been shown to produce beneficial effects in prehypertensives though such was not unequivocal. On the other hand, drugs such as β-adrenoceptor blocking agents were not shown to be useful. Leading clinical guidelines suggest using dietary and lifestyle modifications as a first line interventional strategy to curb the progress of PHTN; however, other clinically respected views call for using drugs. This review provides an overview of the potential pathophysiological processes associated with PHTN, abridges current intervention strategies and suggests investigating the value of using the "Polypill" in prehypertensive subjects to ascertain its potential in delaying (or preventing) CVD associated with raised blood pressure in the presence of other risk factors.

Weight loss maintenance in African American women: a systematic review of the behavioral lifestyle intervention literature

We performed a systematic review of the behavioral lifestyle intervention trials conducted in the United States published between 1990 and 2011 that included a maintenance phase of at least six months, to identify intervention features that promote weight loss maintenance in African American women. Seventeen studies met the inclusion criteria. Generally, African American women lost less weight during the intensive weight loss phase and maintained a lower % of their weight loss compared to Caucasian women. The majority of studies failed to describe the specific strategies used in the delivery of the maintenance intervention, adherence to those strategies, and did not incorporate a maintenance phase process evaluation making it difficult to identify intervention characteristics associated with better weight loss maintenance. However, the inclusion of cultural adaptations, particularly in studies with a mixed ethnicity/race sample, resulted in less % weight regain for African American women. Studies with a formal maintenance intervention and weight management as the primary intervention focus reported more positive weight maintenance outcomes for African American women. Nonetheless, our results present both the difficulty in weight loss and maintenance experienced by African American women in behavioral lifestyle interventions.

ASH position paper: Dietary approaches to lower blood pressure

A substantial body of evidence has implicated several aspects of diet in the pathogenesis of elevated blood pressure (BP). Well-established risk factors for elevated BP include excess salt intake, low potassium intake, excess weight, high alcohol consumption, and suboptimal dietary pattern. African Americans are especially sensitive to the BP-raising effects of excess salt intake, insufficient potassium intake, and suboptimal diet. In this setting, dietary changes have the potential to substantially reduce racial disparities in BP and its consequences. In view of the age-related rise in BP in both children and adults, the direct, progressive relationship of BP with cardiovascular-renal diseases throughout the usual range of BP, and the worldwide epidemic of BP-related disease, efforts to reduce BP in nonhypertensive as well as hypertensive individuals are warranted. In nonhypertensives, dietary changes can lower BP and delay, if not prevent, hypertension. In uncomplicated stage I hypertension, dietary changes serve as initial treatment before drug therapy. In hypertensive individuals already on drug therapy, lifestyle modifications can further lower BP. The current challenge is designing and implementing effective clinical and public health interventions that lead to sustained dietary changes among individuals and more broadly in the general population.

Knowledge and Practice of PHC Physicians toward the Detection and Management of Hypertension and Other CVD Risk Factors in Egypt

Aim. To assess the knowledge and practice of PHC physicians toward the detection and management of hypertension (HTN) and other CVD risk factors. Methods. A cross-sectional study of all primary health care physicians of the FHU of three rural districts of Egypt was conducted. Each physician was subjected to a prevalidated interview questionnaire on the WHO-CVD risk management package for low and medium resources, and a checklist of observation of daily practices. Results. Hypertension was a priority problem in about two-thirds (62.9%) of physicians, yet only 19% have guidelines for HTN patients. Clinical history recording system for HNT was available for 50% of physicians. Levels of knowledge varied with regard to definition of HTN (61.3%, fair), procedures for BP measurement (43.5%, poor), indications for referral (43.5%, poor), patient counseling (61.3%, fair), patient treatment (59.8%, fair). Availability of clinical history recording system for HNT was a significant predictor for physician's level of knowledge (P = 0.001). Overall level of practice was fair (68.5%). Conclusion. PHC physicians have unsatisfactory knowledge and practice on hypertension. There is a need of more continuing medical education. Local and international manuals, workshops, and seminars on how to make use of these guidelines would improve doctors' performance.

A nutrition and physical activity intervention promotes weight loss and enhances diet attitudes in low-income mothers of young children

The purpose of this study was to evaluate a nutrition and physical activity program for reducing body weight and improving nutrition attitudes in mothers of young children. A convenience sample of 114 intervention mothers and 33 comparison mothers was recruited from public health clinics and community centers. Eligibility criteria included Hispanic, African American, or white ethnicity; body mass index of at least 25 kg/m(2); low income (< 200% of the federal poverty index); and youngest child aged 1 to 4 years. For intervention participants, height, weight, percentage of body fat, waist circumference, demographics, nutrition attitudes, and dietary intake were measured at weeks 0 and 8; height, weight, percentage of body fat, and waist circumference were reassessed at 6 months. Overweight mothers in the comparison group provided anthropometric and demographic data at weeks 0 and 8. Changes in anthropometrics, attitudes, and dietary intake were evaluated in intervention mothers. Anthropometric data of intervention vs comparison group mothers were examined. Differences in anthropometrics and attitude scores between weight loss responders (> or = 2.27 kg) and nonresponders (< 2.27 kg) were assessed at week 8. Intervention participants lost weight (x = -2.7 kg; P < .001), whereas comparison mothers gained a slight amount of weight (x = 0.1 kg) by week 8. Weight loss responders had healthier eating attitudes (5.6 vs 5.2; P < .01) and fewer perceived barriers (2.4 vs 2.9; P < .05) than nonresponders postintervention. In conclusion, this dietary and physical activity curriculum is a valuable resource for weight management programs serving low-income women.

A meta-analysis of psycho-behavioral obesity interventions among US multiethnic and minority adults

OBJECTIVE

The present review examines efficacious psycho-behavioral interventions in preventing weight gains or reducing weight among US multiethnic and minority adults as few studies were conducted to review such interventions to date.

METHODS

Data were examined from 24 controlled intervention studies, representing 23 programs and involving 13,326 adults. Studies were identified through manual and online search of databases that include MEDLINE, Academic Search Premier, ERIC, PsycARTICLES, SPORTDiscus, and CINAHL Plus.

RESULTS

Whereas one-component (n=5, d=0.08, 90% CI=-0.04, 0.35) and two-component interventions (n=13, d=0.22, 90% CI=0.05, 0.40) showed a low mean effect size, three-component interventions (n=6, d=0.52, 90% CI=0.39, 0.65) showed a moderate effect size. Interventions conducted in individual sessions (n=15, d=0.40, 90% CI=0.24, 0.56) showed a higher mean effect size than group interventions (n=9, d=0.08, 90% CI=-0.04, 0.30) although the confidence intervals overlapped.

CONCLUSIONS

The study results indicate that future obesity prevention interventions targeting multiethnic and minority adults might benefit from incorporating individual sessions, family involvement, and problem solving strategies into multi-component programs that focus on lifestyle changes.

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.

Body mass index and change in blood pressure over a 7-year period in older Mexican Americans

Obesity and hypertension are major public health concerns in the US. We examined the relationship between body mass index (BMI) and blood pressure in older Mexican Americans using data from the Hispanic Established Population for the Epidemiological Study of the Elderly (EPESE), a longitudinal study of Mexican Americans aged 65 and over residing in the southwestern US. The study sample was 2404 older Mexican American adults with a mean age of 72.6 years of age at baseline (1993–4). Both systolic and diastolic blood pressures were higher in subjects with high BMI categories. The rate of change in systolic blood pressure and diastolic blood pressure were −0.11 mm Hg and −0.32 mm Hg per year over a 7-year period, respectively. The rate of decline in systolic and diastolic blood pressure over a 7-year period was greater in subjects with BMI categories of 25–<30 kg/m² and 30–<35 kg/m² as compared with those subjects with in the lowest and in the highest BMI categories. Hypertension is one of the most prevalent medical conditions affecting older adults. Understanding possible modifiable risk factors that may play a role in the management of hypertension will be beneficial.

Hypertension: trends in prevalence, incidence, and control

Hypertension is the leading cause of cardiovascular disease worldwide. Prior to 1990, population data suggest that hypertension prevalence was decreasing; however, recent data suggest that it is again on the rise. In 1999-2002, 28.6% of the U.S. population had hypertension. Hypertension prevalence has also been increasing in other countries, and an estimated 972 million people in the world are suffering from this problem. Incidence rates of hypertension range between 3% and 18%, depending on the age, gender, ethnicity, and body size of the population studied. Despite advances in hypertension treatment, control rates continue to be suboptimal. Only about one third of all hypertensives are controlled in the United States. Programs that improve hypertension control rates and prevent hypertension are urgently needed.

Synthesis of Intervention Research to Modify Physical Activity and Dietary Behaviors

A descriptive literature review was conducted to examine conceptual and methodological issues of interventions aimed at improving both physical activity and diet behaviors according to critical elements established by Sidani and Braden (1998). The method of the review of 30 articles describing 17 intervention studies focused on the following nine elements: (a) relevance of the intervention to the targeted outcome; (b) theoretical components of the intervention; (c) intervention components; (d) complexity, strength, and integrity of the intervention; (e) extraneous factors; (f) adherence to the intervention and retention; (g) reliability and validity of the outcome measures; (h) expected outcomes; and (i) effectiveness of the intervention. The results were that the interventions were relevant and included multiple components, but most interventions lacked an explicit theoretical framework. Adherence to the intervention and retention were problems. Overall, to varying degrees and for those completing the programs, the interventions were effective for increasing physical activity, lowering dietary fat, weight loss, and reducing risk for illness. Twelve “lessons learned” evolved that have practical and research implications. One salient lesson and future priority is to incorporate theory to reveal the intervention content and mechanisms to modify physical activity and dietary behaviors concurrently so that future interventions are more efficacious and efficient. Another lesson revealed the need for more sensitive measures, and examination of ways to improve intervention adherence and retention and prevent relapse.

Associations of weight loss and changes in fat distribution with the remission of hypertension in a bi-ethnic cohort: the Atherosclerosis Risk in Communities Study

BACKGROUND

To examine associations of weight loss and changes in fat distribution with changes in blood pressure and the remission of hypertension in a community-based sample.

METHODS

Participants were 3245 white and African-American men and women, 45-64 years of age, who participated in the Atherosclerosis Risk in Communities Study over an average of 9 years. Mixed models analyses were used to examine the associations of weight loss and changes in fat distribution with changes in blood pressure. Proportional hazard models with time-dependent covariates were used to examine the associations of weight loss and changes in fat distribution with the remission of hypertension.

RESULTS

Weight loss was associated with a decrease in systolic blood pressure and diastolic blood pressure and with an increased rate of remission of hypertension. Hazard ratios of the remission of hypertension associated with 1-kg increment in annual weight loss were 2.04 (95% confidence interval [CI]: 1.62-2.59), 1.38 (95% CI: 1.14-1.67), 1.84 (95% CI: 1.47-2.29), and 1.53 (95% CI: 1.14-2.05) for white women, African-American women, white men, and African-American men, respectively. Changes in fat distribution were associated with the remission of hypertension in younger (45-54 years) participants.

CONCLUSIONS

Weight loss was associated with a decrease in blood pressure and with remission of hypertension in white and African-American men and women.

Orlistat improves blood pressure control in obese subjects with treated but inadequately controlled hypertension

OBJECTIVE

To investigate the hypothesis that weight reduction with orlistat plus mild caloric restriction leads to better blood pressure control than diet alone in obese individuals with inadequately controlled hypertension. DESIGN This was a 1-year, prospective, randomized, double-blind, placebo-controlled, multicenter trial of orlistat plus diet versus placebo plus diet in obese hypertensives.

INTERVENTIONS

Participants were randomized to receive either orlistat or placebo; all received a 600 kcal deficient diet with no more than 30% of calories from fat. Weight and blood pressure, lipid levels and fasting glucose and insulin levels were followed.

MAIN OUTCOME MEASURES

Patients on orlistat experienced greater weight loss (-5.4 +/- 6.4 versus -2.7 +/- 6.4 kg, P< 0.001) and greater reduction in body mass index (-1.9 +/- 2.3 versus -0.9 +/- 2.2 kg/m2, P<0.001). Target weight loss, defined as > or= 5% body weight (BW), was obtained in more orlistat-treated patients than in the placebo group (46 versus 23%, P<0.001). Diastolic BP decreased more in orlistat-treated patients than in the placebo group (-11.4 +/- 8.3 versus -9.2 +/- 8.4 mmHg, P = 0.002). A greater percentage of orlistat-treated patients reached goal diastolic blood pressure (BP), defined as final diastolic BP< 90 mmHg or a reduction of at least 10 mmHg (67 versus 53%, P< 0.001). The orlistat-treated group had significantly greater reductions in total cholesterol ( P<0.001), low-density lipoprotein cholesterol (P = 0.001) and non-high-density lipoprotein cholesterol (P< 0.005) and target 30% cardiovascular risk reduction was obtained in more orlistat-treated patients (36.1 versus 24.0%, P< 0.04).

CONCLUSION

A weight-loss program with orlistat is more effective than diet alone to lower blood pressure and results in greater cardiovascular risk reduction.

Biobehavioral approaches to the treatment of essential hypertension

Despite recent advances in the medical management of hypertension, chronically elevated blood pressure remains a major health problem in the United States, affecting almost 50 million Americans. It is widely recognized that lifestyle factors contribute to the development and maintenance of elevated blood pressure. This article critically reviews current approaches to the nonpharmacological treatment of high blood pressure and highlights outcome studies of exercise, weight loss and dietary modification, and stress management and relaxation therapies. Methodological issues in the assessment and treatment of hypertension are discussed, along with possible mechanisms by which lifestyle modification may reduce elevated blood pressure.

Quality of life with nonpharmacologic treatment of hypertension

Therapeutic treatment of hypertension has been achieved successfully with both pharmacologic and nonpharmacologic interventions. Clinical trials have shown that various approaches to treatment result in different levels of blood pressure reduction as well as varying effects on quality of life. Standardizing the approach to measuring quality of life would be beneficial to the assessment of treatment outcomes in hypertension trials. This article reviews some of the strengths and weaknesses of both pharmacologic and nonpharmacologic treatments of hypertension, with special emphasis placed on effects of quality of life.

Reduced or modified dietary fat for preventing cardiovascular disease

BACKGROUND

Reduction or modification of dietary fat can improve total cholesterol levels, but may also have a variety of effects, both positive and negative, on other cardiovascular risk factors.

OBJECTIVES

The aim of this systematic review was to assess the effect of reduction or modification of dietary fats on total and cardiovascular mortality and cardiovascular morbidity over at least 6 months, using all available randomized clinical trials.

SEARCH STRATEGY

The Cochrane Library, MEDLINE, EMBASE, CAB Abstracts, CVRCT registry and related Cochrane Groups' trial registers were searched through spring 1998, SIGLE to January 1999. Trials known to experts in the field and biographies were included through May 1999.

SELECTION CRITERIA

Trials fulfilled the following criteria: 1) randomized with appropriate control group, 2) intention to reduce or modify fat or cholesterol intake (excluding exclusively omega-3 fat interventions), 3) not multi factorial, 4) healthy adult humans, 5) intervention at least six months, 6) mortality or cardiovascular morbidity data available. Inclusion decisions were duplicated, disagreement resolved by discussion or a third party.

DATA COLLECTION AND ANALYSIS

Rate data were extracted by two independent reviewers and meta-analysis performed using random effects methodology. Meta-regression and funnel plots were used.

MAIN RESULTS

Twenty seven studies were included (40 intervention arms, 30,901 person-years). There was no significant effect on total mortality (rate ratio 0.98, 95% CI 0.86 to 1.12), a trend towards protection form cardiovascular mortality (rate ratio 0.91, 95% CI 0.77 to 1.07), and significant protection from cardiovascular events (rate ratio 0.84, 95% CI 0.72 to 0.99). The latter became non-significant on sensitivity analysis. Trials where participants were involved for more than 2 years showed significant reductions in the rate of cardiovascular events and a suggestion of protection from total mortality. The degree of protection from cardiovascular events appeared similar in high and low risk groups, but was statistically significant only in the former.

REVIEWER'S CONCLUSIONS

The findings are suggestive of a small but potentially important reduction in cardiovascular risk in trials longer than two years. Lifestyle advice to all those at high risk of cardiovascular disease (especially where statins are unavailable or rationed), and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates.

Effect of body weight changes on changes in ambulatory and standardized non-physician blood pressures over three years

PURPOSE

This study examines the relationship of changes in body mass index (BMI) to changes in measures of both casual and ambulatory blood pressures over three years.

METHODS

In this prospective study of men aged 30-60 years, a cohort of 198 participants was followed for three years. Height, weight, demographic characteristics, and casual and ambulatory measures of blood pressure (BP) were obtained at baseline and 3-year follow-up.

RESULTS

Change in BMI was significantly associated with change in all ambulatory (awake, work, home, and sleep) and casual systolic and diastolic blood pressures. After controlling for age and race/ethnicity, the association remained significant for nine of the twelve BP change measures. Further tests show that the effect of a change in BMI on BP change does not vary across the six systolic blood pressures or across the six diastolic measures. An average-height man gaining 5 kg (11 pounds) typically exhibited a 2.5 mm Hg increase in systolic and a 1.8 mm Hg increase in diastolic casual and ambulatory BPs. There is no evidence that changes in BP were associated with age, race/ethnicity (blacks vs. Hispanics vs. whites), or the average of the baseline and follow-up levels of BMI. In addition, the impact of weight gain is similar in magnitude, but in the opposite direction, to that of weight loss.

CONCLUSIONS

Changes in BMI over three years predict changes in ambulatory and standardized non-physician BPs. These changes in BP are not related to average BMI level or age.

Weight change, ideal weight and hypertension

A growing body of evidence supports the fact that body weight is related to blood pressure. The risk of hypertension increases with increasing body mass index and weight gain; and weight loss reduces blood pressure. Birthweight may also be linked to adult blood pressure, possibly as a result of its relationship with later obesity.

A review of long-term studies evaluating the efficacy of weight loss in ameliorating disorders associated with obesity

Obesity leads to and exacerbates many serious disorders, including hypertension, dyslipidemia, cardiovascular disease, non-insulin-dependent diabetes mellitus, gallbladder disease, respiratory dysfunction, gout, and osteoarthritis. Many short-term studies have shown that weight loss can ameliorate or, in some cases, reverse such disorders. Fewer long-term studies-defined as those whose combined acute intervention and follow-up phases extend for at least 1 year-of the therapeutic benefits of weight loss on specific disorders have been undertaken. Those long-term studies that have been performed tend to confirm the results of briefer studies. Even when weight loss has been comparatively modest or some degree of weight regain has occurred, weight loss is generally associated with a decrease in risk factors and the alleviation of clinical symptoms.

The U-shaped association between body mass index and mortality: relationship with weight gain in a Native American population

In order to determine whether weight loss explains high mortality rates in those with a low body mass index (BMI), the relationships between BMI, rate of weight gain and mortality were examined in Pima Indians. Subjects were 814 diabetic and 1814 nondiabetic participants in a longitudinal survey who had at least two examinations after age 20. Median duration of follow-up was 8.1 (range 0.03-25.1) years. BMI showed a U-shaped relationship with mortality rates in men with the lowest rates in the 30-35 kg/m2 category; an inverse relationship was seen in women. Subjects who were losing weight had higher mortality rates than those who were gaining. However, excess mortality among the lightest subjects was present among those who were gaining weight. Among nondiabetic subjects, the mortality ratio (MR) for BMI < 25 kg/m2 compared with 30-35 kg/m2 was 1.5 [95% confidence interval (CI) 1.0-2.2] unadjusted for weight gain, while the adjusted MR was 1.3 [95% CI 0.9-1.9]. Weight loss, which may reflect underlying illness, is associated with high mortality rates in Pima Indians but does not fully account for the high mortality in the lightest individuals.

Trials of Hypertension Prevention, phase II. Structure and content of the weight loss and dietary sodium reduction interventions. Trials of Hypertension Prevention (TOHP) Collaborative Research Group

Identifying effective, nonpharmacologic means of preventing or significantly delaying the onset of hypertension would be a major advance in the primary prevention of cardiovascular disease. In the first phase of the Trials of Hypertension Prevention (TOHP I), adults with high-normal diastolic blood pressure were randomly assigned to one of seven nonpharmacologic interventions. Only weight loss and reduction of dietary sodium proved to be effective strategies for reducing blood pressure. The second phase of TOHP (TOHP II) will test the effectiveness of weight loss, reduction of dietary sodium, and their combination of lowering blood pressure and preventing the onset of hypertension over a 3- to 4-year follow-up period. This article describes the three interventions used in TOHP II, methods used to maintain continued participation in this long-term trial, and protocol enhancements designed to maximize intervention effectiveness.

The effect of potassium supplementation in persons with a high-normal blood pressure. Results from phase I of the Trials of Hypertension Prevention (TOHP). Trials of Hypertension Prevention (TOHP) Collaborative Research Group

We conducted a randomized, double-blind, placebo-controlled trial of oral potassium chloride supplementation (60 mmol/d) in 353 men and women with an initial average diastolic blood pressure between 80 and 89 mm Hg. In the active (n = 178) compared to the placebo (n = 175) treatment group, the urinary potassium level was significantly (p < 0.001) increased by an average of 44.0 and 42.3 mmol/24 h following 3 and 6 months of therapy, respectively. Compared to placebo, active treatment was associated with a small (mean = 1.8 mm Hg) but significant (p = 0.04) reduction in diastolic blood pressure following 3 months of therapy. Following 6 months, however, this apparent treatment effect had virtually disappeared (mean reduction in diastolic blood pressure = 0.3 mm Hg). There was no significant effect of potassium supplementation on systolic blood pressure at either follow-up visit. There was a significant, independent, dose-response relationship between change in both 24-hour urinary potassium excretion and urinary sodium-potassium ratio and the corresponding change in diastolic blood pressure (-1.49 mm Hg for the highest versus the lowest quartile of change in urinary potassium excretion.