Longitudinal Profiling of Fasting Plasma Metabolome in Response to Weight-Loss Interventions in Patients with Morbid Obesity.

It is well recognized that patients with severe obesity exhibit remarkable heterogeneity in response to different types of weight-loss interventions. Those who undergo Roux-en-Y gastric bypass (RYGB) usually exhibit more favorable glycemic outcomes than those who receive adjustable gastric banding (BAND) or intensive medical intervention (IMI). The molecular mechanisms behind these observations, however, remain largely unknown. To identify the plasma metabolites associated with differential glycemic outcomes induced by weight-loss intervention, we studied 75 patients with severe obesity (25 each in RYGB, BAND, or IMI). Using untargeted metabolomics, we repeatedly measured 364 metabolites in plasma samples at baseline and 1-year after intervention. Linear regression was used to examine whether baseline metabolites or changes in metabolites are associated with differential glycemic outcomes in response to different types of weight-loss intervention, adjusting for sex, baseline age, and BMI as well as weight loss. Network analyses were performed to identify differential metabolic pathways involved in the observed associations. After correction for multiple testing (q < 0.05), 33 (RYGB vs. IMI) and 28 (RYGB vs. BAND) baseline metabolites were associated with changes in fasting plasma glucose (FPG) or glycated hemoglobin (HbA1c). Longitudinal changes in 38 (RYGB vs. IMI) and 38 metabolites (RYGB vs. BAND) were significantly associated with changes in FPG or HbA1c. The identified metabolites are enriched in pathways involved in the biosynthesis of aminoacyl-tRNA and branched-chain amino acids. Weight-loss intervention evokes extensive changes in plasma metabolites, and the altered metabolome may underlie the differential glycemic outcomes in response to different types of weight-loss intervention, independent of weight loss itself.

Predictors of racial differences in weight loss: the PROPEL trial.

OBJECTIVE: Studies have consistently shown that African American individuals lose less weight in response to behavioral interventions, but the mechanisms leading to this result have been understudied. METHODS: Data were derived from the PROmoting Successful Weight Loss in Primary CarE in Louisiana (PROPEL) study, which was a cluster-randomized, two-arm trial conducted in primary care clinics. In the PROPEL trial, African American individuals lost less weight compared with patients who belonged to other racial groups after 24 months. In the current study, counterfactual mediation analyses among 445 patients in the intervention arm of PROPEL were used to determine which variables mediated the relationship between race and weight loss. The mediators included treatment engagement, psychosocial, and lifestyle factors. RESULTS: At 6 months, daily weighing mediated 33% (p = 0.008) of the racial differences in weight loss. At 24 months, session attendance and daily weighing mediated 35% (p = 0.027) and 66% (p = 0.005) of the racial differences in weight loss, respectively. None of the psychosocial or lifestyle variables mediated the race-weight loss association. CONCLUSIONS: Strategies specifically targeting engagement, such as improving session attendance and self-weighing behaviors, among African American individuals are needed to support more equitable weight losses over extended time periods.

DNA methylation is differentially associated with glycemic outcomes by different types of weight-loss interventions: an epigenome-wide association study.

BACKGROUND: Alterations in DNA methylation (DNAm) have been reported to be a mechanism by which bariatric surgeries resulted in considerable metabolic improvements. Previous studies have mostly focused on change in DNAm following weight-loss interventions, yet whether DNAm prior to intervention can explain the variability in glycemic outcomes has not been investigated. Here, we aim to examine whether baseline DNAm is differentially associated with glycemic outcomes induced by different types of weight-loss interventions. METHODS: Participants were 75 adults with severe obesity who underwent non-surgical intensive medical intervention (IMI), adjustable gastric band (BAND) or Roux-en-Y gastric bypass (RYGB) (n = 25 each). Changes in fasting plasma glucose (FPG) and glycated hemoglobin (HbA1c) were measured at 1-year after intervention. DNAm was quantified by Illumina 450 K arrays in baseline peripheral blood DNA. Epigenome-wide association studies were performed to identify CpG probes that modify the effects of different weight-loss interventions on glycemic outcomes, i.e., changes in FPG and HbA1c, by including an interaction term between types of intervention and DNAm. Models were adjusted for weight loss and baseline clinical factors. RESULTS: Baseline DNAm levels at 3216 and 117 CpGs were differentially associated with changes in FPG and HbA1c, respectively, when comparing RYGB versus IMI. Of these, 79 CpGs were significant for both FPG and HbA1c. The identified genes are enriched in adaptive thermogenesis, temperature homeostasis and regulation of cell population proliferation. Additionally, DNAm at 6 CpGs was differentially associated with changes in HbA1c when comparing RYGB versus BAND. CONCLUSIONS: Baseline DNAm is differentially associated with glycemic outcomes in response to different types of weight-loss interventions, independent of weight loss and other clinical factors. Such findings provided initial evidence that baseline DNAm levels may serve as potential biomarkers predictive of differential glycemic outcomes in response to different types of weight-loss interventions.

Changes in mood and health-related quality of life in Look AHEAD 6 years after termination of the lifestyle intervention.

OBJECTIVE: The Action for Health in Diabetes (Look AHEAD) study previously reported that intensive lifestyle intervention (ILI) reduced incident depressive symptoms and improved health-related quality of life (HRQOL) over nearly 10 years of intervention compared with a control group (the diabetes support and education group [DSE]) in participants with type 2 diabetes and overweight or obesity. The present study compared incident depressive symptoms and changes in HRQOL in these groups for an additional 6 years following termination of the ILI in September 2012. METHODS: A total of 1,945 ILI participants and 1,900 DSE participants completed at least one of four planned postintervention assessments at which weight, mood (via the Patient Health Questionnaire-9), antidepressant medication use, and HRQOL (via the Medical Outcomes Scale, Short Form-36) were measured. RESULTS: ILI participants and DSE participants lost 3.1 (0.3) and 3.8 (0.3) kg [represented as mean (SE); p = 0.10], respectively, during the 6-year postintervention follow-up. No significant differences were observed between groups during this time in incident mild or greater symptoms of depression, antidepressant medication use, or in changes on the physical component summary or mental component summary scores of the Short Form-36. In both groups, mental component summary scores were higher than physical component summary scores. CONCLUSIONS: Prior participation in the ILI, compared with the DSE group, did not appear to improve subsequent mood or HRQOL during 6 years of postintervention follow-up.

Weight Loss in Underserved Patients - A Cluster-Randomized Trial.

BACKGROUND: Evidence of the effectiveness of treatment for obesity delivered in primary care settings in underserved populations is lacking. METHODS: We conducted a cluster-randomized trial to test the effectiveness of a high-intensity, lifestyle-based program for obesity treatment delivered in primary care clinics in which a high percentage of the patients were from low-income populations. We randomly assigned 18 clinics to provide patients with either an intensive lifestyle intervention, which focused on reduced caloric intake and increased physical activity, or usual care. Patients in the intensive-lifestyle group participated in a high-intensity program delivered by health coaches embedded in the clinics. The program consisted of weekly sessions for the first 6 months, followed by monthly sessions for the remaining 18 months. Patients in the usual-care group received standard care from their primary care team. The primary outcome was the percent change from baseline in body weight at 24 months. RESULTS: All 18 clinics (9 assigned to the intensive program and 9 assigned to usual care) completed 24 months of participation; a median of 40.5 patients were enrolled at each clinic. A total of 803 adults with obesity were enrolled: 452 were assigned to the intensive-lifestyle group, and 351 were assigned to the usual-care group; 67.2% of the patients were Black, and 65.5% had an annual household income of less than $40,000. Of the enrolled patients, 83.4% completed the 24-month trial. The percent weight loss at 24 months was significantly greater in the intensive-lifestyle group (change in body weight, -4.99%; 95% confidence interval [CI], -6.02 to -3.96) than in the usual-care group (-0.48%; 95% CI, -1.57 to 0.61), with a mean between-group difference of -4.51 percentage points (95% CI, -5.93 to -3.10) (P<0.001). There were no significant between-group differences in serious adverse events. CONCLUSIONS: A high-intensity, lifestyle-based treatment program for obesity delivered in an underserved primary care population resulted in clinically significant weight loss at 24 months. (Funded by the Patient-Centered Outcomes Research Institute and others; PROPEL ClinicalTrials.gov number, NCT02561221.).

HEADS UP: Design and Methods of a Louisiana State-Funded Surgical and Non-Surgical Weight Loss Program.

This paper describes the methodology, design and procedures used in the HEADS UP Project, an observational study to examine the feasibility of a state-funded weight loss program. HEADS UP offered two weight loss approaches: bariatric surgery or a non-surgical intervention composed of medical management, a low-calorie liquid diet and lifestyle change promotion. Participants were recruited through a multi-stage screening process, in-person interviews, and an initial low-calorie diet program. Eligible participants were entered into a lottery system, with 100 participants selected for the surgical group and 200 selected for the non-surgical group annually for five years. Anthropometric, clinical, and psychosocial assessments were completed at baseline and follow-ups. More than 6800 individuals completed the initial web screening. Screening procedures yielded 1412 participants (490 surgical and 922 non-surgical). Approximately 84% of the total participant population were female and 38% were Black. Participants had an average body mass index of 47.9 and 43 kg/m2 in the surgical and non-surgical groups, respectively. Recruitment and enrollment results of the HEADS UP study demonstrated significant interest in both the surgical and non-surgical treatment programs for obesity. These results support the feasibility of providing a state-funded weight loss program within a healthcare setting.

Promoting Successful Weight Loss in Primary Care in Louisiana (PROPEL): Rationale, design and baseline characteristics.

Underserved and minority populations suffer from a disproportionately high prevalence of obesity and related comorbidities. Effective obesity treatment programs delivered in primary care that produce significant weight loss are currently lacking. The purpose of this trial is to test the effectiveness of a pragmatic, high intensity lifestyle-based obesity treatment program delivered within primary care among an underserved population. We hypothesize that, relative to patients who receive usual care, patients who receive a high-intensity, health literacy- and culturally-appropriate lifestyle intervention will have greater percent reductions in body weight over 24 months. Eighteen clinics (N = 803 patients) serving low income populations with a high proportion of African Americans in Louisiana were randomized to the intervention or usual car. Patients in the intervention participate in a high-intensity lifestyle program delivered by health coaches employed by an academic health center and embedded in the primary care clinics. The program consists of weekly (16 in-person/6 telephone) sessions in the first six months, followed by sessions held at least monthly for the remaining 18 months. Primary care practitioners in usual care receive information on weight management and the current Centers for Medicare and Medicaid Services reimbursement for obesity treatment. The primary outcome is percent weight loss at 24 months. Secondary outcomes include absolute 24-month changes in body weight, waist circumference, blood pressure, fasting glucose and lipids, health-related quality of life, and weight-related quality of life. The results will provide evidence on the effectiveness of implementing high-intensity lifestyle and obesity counseling in primary care settings among underserved populations. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT02561221.

Family PArtners in Lifestyle Support (PALS): Family-based weight loss for African American adults with type 2 diabetes.

OBJECTIVE: To develop and test a family-centered behavioral weight loss intervention for African American adults with type 2 diabetes. METHODS: In this randomized trial, dyads consisting of an African American adult with overweight or obesity and type 2 diabetes (index participant) paired with a family partner with overweight or obesity but not diagnosed with diabetes were assigned in a 2:1 ratio to a 20-week special intervention (SI) or delayed intervention (DI) control group. The primary outcome was weight loss among index participants at the 20-week follow-up. RESULTS: One hundred eight participants (54 dyads-36 (SI) and 18 (DI) dyads) were enrolled: 81% females; mean age, 51 years; mean weight,103 kg; and mean BMI, 37 kg/m2 . At post-intervention, 96 participants (89%) returned for follow-up measures. Among index participants, mean difference in weight loss between groups was -5.0 kg, P <0.0001 (-3.6 kg loss among SI; 1.4 kg gain in DI). SI index participants showed significantly greater improvements in hemoglobin A1c, depressive symptoms, family interactions, and dietary, physical activity, and diabetes self-care behaviors. SI family partners also had significant weight loss (-3.9 kg (SI) vs. -1.0 kg (DI), P = 0.02). CONCLUSIONS: A family-centered, behavioral weight loss intervention led to clinically significant short-term weight loss among family dyads.

The impact of continued intervention on weight: Five-year results from the weight loss maintenance trial.

OBJECTIVE: In the Weight Loss Maintenance (WLM) Trial, a personal contact (PC) intervention sustained greater weight loss relative to a self-directed (SD) group over 30 months. This study investigated the effects of continued intervention over an additional 30 months and overall weight change across the entire WLM Trial. METHODS: WLM had 3 phases. Phase 1 was a 6-month weight loss program. In Phase 2, those who lost ≥4 kg were randomized to a 30-month maintenance trial. In Phase 3, PC participants (n = 196, three sites) were re-randomized to no further intervention (PC-Control) or continued intervention (PC-Active) for 30 more months; 218 SD participants were also followed. RESULTS: During Phase 3, weight increased 1.0 kg in PC-Active and 0.5 kg in PC-Control (mean difference 0.6 kg; 95% CI:-1.4 to 2.7; P = 0.54). Mean weight change over the entire study was -3.2 kg in those originally assigned to PC (PC-Combined) and -1.6 kg in SD (mean difference -1.6 kg; 95% CI:-3.0 to -0.1; P = 0.04). CONCLUSIONS: After 30 months of the PC maintenance intervention, continuation for another 30 months provided no additional benefit. However, across the entire study, weight loss was slightly greater in those originally assigned to PC.

Predictors for selection of insurance-funded weight loss approaches in individuals with severe obesity.

OBJECTIVE: To determine whether there are differences in baseline psychological and behavioral characteristics between individuals with severe obesity who chose a surgical or nonsurgical intervention for weight loss. METHODS: The current study utilized data from a larger study funded by a state insurance company and is unique in that the insurance company funded the weight loss interventions. Participants indicated their preferred method of weight loss, and completed several self-report psychological questionnaires, as well as demographic information. RESULTS: Participants (N = 605) were 58.8% Caucasian and mostly (86%) female. Logistic regression results indicated that an increased number of weight loss attempts, and select other measures of eating behavior and quality of life may influence individuals' selection for either surgical or nonsurgical treatments for weight loss. CONCLUSIONS: Practitioners should pay particular attention to these baseline characteristics that influence choice to examine potential characteristics that may influence the success of these weight loss treatments.

Application of Latent Class Analysis to Identify Behavioral Patterns of Response to Behavioral Lifestyle Interventions in Overweight and Obese Adults.

BACKGROUND: Examining responders and non-responders to behavioral lifestyle interventions among overweight/obese adults with additional comorbidities may aid in refining and tailoring obesity treatment. PURPOSE: The purpose of this study is to demonstrate the use of latent class analysis to identify patterns of response to behavioral lifestyle interventions based on adherence to diet and exercise recommendations. METHOD: Repeated measures latent class analysis was applied to two clinical trial datasets, combination of two active interventions in the PREMIER Trial (n = 501) and phase 1 of the Weight Loss Maintenance Trial (WLM; n = 1685), to identify patterns of response to behavioral lifestyle interventions. Treatment response was based on adherence to daily recommendations for fruit/vegetable, fat, saturated fat, sodium, and exercise at baseline and 6 months. RESULTS: In PREMIER, three distinct latent classes emerged: responders (45.9%), non-responders (23.6%), and early adherers (30.5%). Responders and Early Adherers had greater weight loss at 6 and 18 months and were more likely to meet behavioral recommendations at 18 months than Non-responders. For WLM, there were four latent classes: partial responders (16%), non-responders (40%), early adherers (2%), and fruit/veggie only responders (41%). Non-responders in WLM had significantly less weight loss at 6 months compared to that of the other three latent classes. CONCLUSION: Latent class analysis is a useful method to apply to clinical trial data to identify distinct patterns of response to behavioral interventions. Overweight/ obese participants who respond to behavioral lifestyle treatment (i.e., meet behavioral recommendations) have significantly greater weight loss than that of participants who do not make behavioral changes.

Five-year medical and pharmacy costs after a medically supervised intensive treatment program for obesity.

PURPOSE: The financial impact of intensive medical interventions for weight loss has not been fully studied. DESIGN: A randomized pragmatic clinical trial. SETTING: Seven primary care clinics and one research center in Louisiana. SUBJECTS: Severely obese individuals (body mass index 40-60 kg/m(2)) randomized to usual care (n = 190) or intensive medical management (n = 200). Forty-seven percent of participants completed year 2 follow-up and were included in the analyses. INTERVENTION: Physician-monitored intervention with recommendations for 12 weeks of liquid diet followed by 4 months of group behavioral therapy, structured diet, and option of pharmacotherapy, and an additional 16 months of maintenance strategies. MEASURES: Two-year preintervention and 5-year postintervention measures were computed from claims data and included (1) medical costs excluding pharmacy, (2) pharmacy costs only, (3) total medical and pharmacy costs, and (4) medical and pharmacy subcategory costs. ANALYSIS: Differential categories for preintervention and postintervention were created using total sample 75th percentiles. Chi-square tests were employed to compare the intervention groups both preintervention and postintervention with respect to the proportion of subjects above the 75th percentile for each of the cost categories. RESULTS: Medical costs excluding pharmacy did not differ between groups. The intensive medical intervention group had a significantly smaller percentage of subjects above the 75th percentile for pharmacy costs only (p = .0125), and for antidiabetic agents (p = .0464), antihypertensives (p = .0075), and dyslipidemic subcategories (p = .0197). CONCLUSION: An intensive medical intervention may reduce pharmaceutical expenditures in severely obese individuals. These results must be viewed with caution given the high attrition of study participants.

Psychosocial predictors of weight regain in the weight loss maintenance trial.

This study's purpose was to identify psychosocial predictors of weight loss maintenance in a multi-site clinical trial, following a group-based weight loss program. Participants (N = 1025) were predominately women (63%) and 38% were Black (mean age = 55.6 years; SD = 8.7). At 12 months, higher SF-36 mental health composite scores were associated with less weight regain (p < .01). For Black participants, an interaction existed between race and friends' encouragement for exercise, where higher exercise encouragement was related to more weight regain (p < .05). At 30 months, friends' encouragement for healthy eating was associated with more weight regain (p < .05), whereas higher SF-36 mental health composite scores were related to less weight regain (p < .0001). Perceived stress and select health-related quality of life indices were associated with weight regain; this relationship varied across gender, race, and treatment conditions. Temporal changes in these variables should be investigated for their impact on weight maintenance.

Why patients seek bariatric surgery: does insurance coverage matter?

Despite increasing prevalence of bariatric surgery, little is known about why patients seek out this treatment option. Heads Up is an observational study sponsored by a large benefits management group that examines surgical and nonsurgical approaches to weight management in obese adults. This study examined patients' reasons for choosing surgery. The sample included 360 adult obese patients seeking bariatric surgery who were invited to volunteer for a surgical or a medical weight loss program by their insurer. Participants rank ordered their top three reasons as a deciding factor for choosing to consider surgery. The top three reasons were concerns regarding health (52%), current obesity-related medical conditions (28%), and improved physical fitness (5%). Overall, 13% endorsed insurance coverage as one of their top three choices. When insurance coverage is assured, health and functionality issues were the major reasons reported for obese adults choosing to undergo bariatric surgery.

Hyperphagia: current concepts and future directions proceedings of the 2nd international conference on hyperphagia.

OBJECTIVE: Hyperphagia is a central feature of inherited disorders (e.g., Prader-Willi Syndrome) in which obesity is a primary phenotypic component. Hyperphagia may also contribute to obesity as observed in the general population, thus raising the potential importance of common underlying mechanisms and treatments. Substantial gaps in understanding the molecular basis of inherited hyperphagia syndromes are present as are a lack of mechanistic of mechanistic targets that can serve as a basis for pharmacologic and behavioral treatments. DESIGN AND METHODS: International conference with 28 experts, including scientists and caregivers, providing presentations, panel discussions, and debates. RESULTS: The reviewed collective research and clinical experience provides a critical body of new and novel information on hyperphagia at levels ranging from molecular to population. Gaps in understanding and tools needed for additional research were identified. CONCLUSIONS: This report documents the full scope of important topics reviewed at a comprehensive international meeting devoted to the topic of hyperphagia and identifies key areas for future funding and research.

Predictors of dietary change among those who successfully lost weight in phase I of the Weight Loss Maintenance Trial.

AIM: Dietary changes occurring during weight loss interventions can vary. The present study tested if pretreatment psychosocial, dietary and demographic factors were associated with changes in fat intake and fruit and vegetable intake during a weight loss intervention. METHODS: This analysis includes participants who lost at least four kilograms during the initial six month weight loss phase (phase I) of the Weight Loss Maintenance Trial, a group format behavioural intervention emphasising a low-fat diet and increased physical activity. Multiple linear regression was used to determine associations between pretreatment psychosocial, dietary, physical activity, and demographic variables and changes from pretreatment to six months in fat intake and fruit and vegetable intake. RESULTS: Participants (n = 1032) were 63.4% female, 62.4% non-African American, and had a mean age of 55.6 and BMI of 34.1 kg/m2. Being African American (P < 0.0001) and higher baseline kilojoule intake (P < 0.01) were associated with smaller reductions in fat intake. Being African American (p < 0.001) and older age (P = 0.02) were associated with smaller increases in fruit and vegetable intake, whereas a history of 10 or more past weight loss episodes of at least 10 lb (4.5 kg; P < 0.01) was associated with greater increases. CONCLUSIONS: Few psychosocial factors examined contributed to variability in dietary change. Even when achieving meaningful weight losses during a behavioural weight loss intervention, African Americans may make fewer beneficial changes in fat and fruit and vegetable intake than non-African Americans.

Greater weight loss with increasing age in the weight loss maintenance trial.

OBJECTIVE: To determine the effect of age on weight loss and weight loss maintenance in participants in the Weight Loss Maintenance trial (WLM). DESIGN AND METHODS: Secondary analysis of a randomized controlled trial of overweight/obese adults with CVD risk factors was conducted. Participants were 1685 adults with baseline BMI 25-45 kg m(2) with hypertension and/or dyslipidemia. Those who lost at least 4kg in an initial 6-month behavioral weight loss intervention (N = 1,032) were randomly assigned to a 30-month maintenance phase of self-directed control (SD), monthly personal counseling (PC), or unlimited access to an internet-based intervention (IT). Age groups were defined post-hoc and weight change was compared among age groups. RESULTS: Participants ≥60 years old initially lost more weight than younger individuals, and sustained greater weight loss in IT and PC but not in SD (P value for trend 0.024, 0.002, and 0.36, respectively). CONCLUSIONS: In WLM, adults age ≥60 years had greater initial weight loss and greater sustained weight loss over 3 years, compared to younger adults. Older adults had greater weight loss maintenance with either personal counseling or internet-based intervention. Future research should determine optimal implementation strategies and effects of weight loss on health outcomes in older adults.

Examining behavioral processes through which lifestyle interventions promote weight loss: results from PREMIER.

OBJECTIVE: To examine the behavioral processes through which lifestyle interventions impacted weight loss. METHODS: The analyses were limited to overweight and obese Black and White adults randomized to a PREMIER lifestyle intervention (N = 501). Structural equation modeling was conducted to test the direct and indirect relationships of session attendance, days of self-monitoring diet and exercise, change in diet composition and exercise, and 6-month weight change. RESULTS: Greater session attendance was associated with increased self-monitoring, which was in turn significantly related to reduction in percent energy from total fat consumed. Change in percent energy from fat and self-monitoring was associated with 6-month percent change in weight. Both a decrease in fat intake and increase in self-monitoring are potential mediators of the relationship between attendance and weight change. CONCLUSIONS: The findings provide a reasonable model that suggests regular session attendance and use of behavioral strategies like self-monitoring are associated with improved behavioral outcomes that are associated with weight loss.

Impact of 5-year weight change on blood pressure: results from the Weight Loss Maintenance trial.

In this secondary analysis of the Weight Loss Maintenance trial, the authors assessed the relationship between blood pressure (BP) change and weight change in overweight and obese adults with hypertension and/or dyslipidemia who were randomized to 1 of 3 weight loss maintenance strategies for 5 years. The participants were grouped (N=741) based on weight change from randomization to 60 months as: (1) weight loss, (2) weight stable, or (3) weight gain. A significant positive correlation between weight change and systolic BP (SBP) change at 12, 30, and 60 months and between weight change and diastolic BP (DBP) change at 30 months was observed. From randomization to 60 months, mean SBP increased to a similar degree for the weight gain group (4.2±standard error=0.6 mm Hg; P<.001) and weight stable group (4.6±1.1 mm Hg; P<.001), but SBP did not rise in the weight loss group (1.0±1.7 mm Hg, P=.53). DBP was unchanged for all groups at 60 months. Although aging may have contributed to rise in BP at 60 months, it does not appear to fully account for observed BP changes. These results suggest that continued modest weight loss may be sufficient for long-term BP lowering.

Self-efficacy as a predictor of weight change and behavior change in the PREMIER trial.

OBJECTIVES: Determine whether self-efficacy independently predicted weight loss in a behavioral intervention and explore factors that influence the path between self-efficacy and weight change. DESIGN: Secondary analysis of the PREMIER trial, a randomized controlled trial testing effects of lifestyle interventions on blood pressure. SETTING: Four academic medical centers. PARTICIPANTS: PREMIER recruited adults (n = 810) with pre-hypertension/stage 1 hypertension, not currently receiving medication. This analysis excluded participants in the control arm, resulting in n = 537. INTERVENTIONS: Participants were randomly assigned to 1 of 3 groups: advice only, established lifestyle recommendations, or established lifestyle recommendations plus Dietary Approaches to Stop Hypertension dietary pattern. MAIN OUTCOME MEASURES: Self-efficacy (dietary self-efficacy [DSE], exercise self-efficacy [ESE]), dietary intake, fitness. ANALYSIS: Pearson correlations, 1-way analysis of variance, mediation analyses. RESULTS: Despite an overall decrease in DSE/ESE, change in DSE/ESE significantly predicted weight change at 6 (ß = -.21, P < .01; ß = -.19, P < .01, respectively) and 18 months (ß = -.19, P < .01; ß = -.35, P < .01). Change in percent calories from fat partially mediated the DSE/weight change relationship at 6 months. Change in fitness partially mediated the ESE/weight change relationship at 18 months. CONCLUSIONS AND IMPLICATIONS: Changes in DSE/ESE were not associated with behavior change as hypothesized. Additional research is needed to identify mediators between self-efficacy and adoption of behaviors that influence weight loss.