Dataset Information

Weight change among people randomized to minimal intervention control groups in weight loss trials.

ABSTRACT: Evidence on the effectiveness of behavioral weight management programs often comes from uncontrolled program evaluations. These frequently make the assumption that, without intervention, people will gain weight. The aim of this study was to use data from minimal intervention control groups in randomized controlled trials to examine the evidence for this assumption and the effect of frequency of weighing on weight change.Data were extracted from minimal intervention control arms in a systematic review of multicomponent behavioral weight management programs. Two reviewers classified control arms into three categories based on intensity of minimal intervention and calculated 12-month mean weight change using baseline observation carried forward. Meta-regression was conducted in STATA v12.Thirty studies met the inclusion criteria, twenty-nine of which had usable data, representing 5,963 participants allocated to control arms. Control arms were categorized according to intensity, as offering leaflets only, a single session of advice, or more than one session of advice from someone without specialist skills in supporting weight loss. Mean weight change at 12 months across all categories was -0.8 kg (95% CI -1.1 to -0.4). In an unadjusted model, increasing intensity by moving up a category was associated with an additional weight loss of -0.53 kg (95% CI -0.96 to -0.09). Also in an unadjusted model, each additional weigh-in was associated with a weight change of -0.42 kg (95% CI -0.81 to -0.03). However, when both variables were placed in the same model, neither intervention category nor number of weigh-ins was associated with weight change.Uncontrolled evaluations of weight loss programs should assume that, in the absence of intervention, their population would weigh up to a kilogram on average less than baseline at the end of the first year of follow-up.

SUBMITTER: Johns DJ

PROVIDER: S-EPMC4820081 | biostudies-other | 2016 Apr

REPOSITORIES: biostudies-other

ACCESS DATA

Similar Datasets

Project description:Circulating amino acids, such as branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs), have been associated with diabetes risk; however, little is known about how a long-term dietary intervention for weight loss affects circulating amino acids.We examined the effects of weight-loss diets on long-term changes in plasma amino acids and the associations of these changes with weight loss and the improvement of insulin resistance.We repeatedly measured plasma amino acid profiles over 2 y in overweight or obese participants from 2 randomized, dietary intervention, weight-loss trials [774 subjects from the POUNDS LOST (Preventing Overweight Using Novel Dietary Strategies Trial) and 318 subjects from the DIRECT (Dietary Intervention Randomized Controlled Trial)].Intervention diets consistently lowered most of the amino acid concentrations, including BCAAs and AAAs, in both trials. In the POUNDS LOST, average-protein diets (15% of daily energy) showed stronger effects than did high-protein diets (25% of daily energy) on reducing concentrations of the diabetes-associated BCAA valine at 6 mo independent of the weight change. In both trials, weight loss was directly related to the concurrent reduction of the BCAAs leucine and isoleucine, the AAAs tyrosine and phenylalanine, and 4 other amino acids. For example, per kilogram of weight loss, there was a 0.04-SD decrease in log tyrosine (?0.6 ?mol/L) in both trials. In addition, we showed that reductions in alanine and the AAA tyrosine were significantly related to improved insulin resistance (measured with the use of the homeostasis model assessment of insulin resistance), independent of weight loss, in both trials (both P < 0.05). For example, per 1-SD decrease in log tyrosine (?17 ?mol/L), there was a 0.04-SD (?3%) improvement in insulin resistance in the POUNDS LOST and a 0.13-SD (?8%) improvement in insulin resistance in the DIRECT.Our findings underscore the potential importance of dietary interventions in improving amino acid profiles (i.e., reducing diabetes risk-enhancing amino acid concentrations) along with and beyond weight loss. The POUNDS LOST and the DIRECT were registered at clinicaltrials.gov as NCT00072995 and NCT00160108, respectively.

Project description:Randomized clinical trials (RCTs) of lifestyle modification have reported beneficial effects of interventions, compared to control. Whether participation in the control group has benefits is unknown. To determine whether control group participants experience weight loss during the course of RCTs. After prospective registration (PROSPERO CRD42021233070), we conducted searches in Medline, Scopus, Web of Science, Cochrane library and Clinicaltrials.gov databases from inception to May 2021 without language restriction to capture RCTs on dietary advice or physical activity interventions in adults with overweight, obesity or metabolic syndrome. Data extraction and study quality assessment was performed by two independent reviewers. Weight loss in the control group, i.e., the difference between baseline and post-intervention, was pooled using random effects model generating mean difference and 95% confidence interval (CI). Heterogeneity was assessed using the I2 statistical test. Subgroup meta-analysis was performed stratifying by follow-up period, type of control group protocols and high-quality studies. Among the 22 included studies (4032 participants), the risk of bias was low in 9 (40%) studies. Overall, the controls groups experienced weight loss of - 0.41 kg (95% CI - 0.53 to - 0.28; I2 = 73.5% p < 0.001). To identify a result that is an outlier, we inspected the forest plot for spread of the point estimates and the confidence intervals. The magnitude of the benefit was related to the duration of follow-up (- 0.51 kg, 95% CI - 0.68, - 0.3, for 1-4 months follow-up; - 0.32 kg, 95% CI - 0.58, - 0.07, 5-12 months; - 0.20 kg, 95% CI - 0.49, 0.10, ≥ 12 months). In high-quality studies we found an overall weight loss mean difference of - 0.16 (95% CI - 0.39, 0.09) with a considerable heterogeneity (I2 = 74%; p < 0.000). Among studies including control group in waiting lists and combining standard care, advice and material, no heterogeneity was found (I2 = 0%, p = 0.589) and (I2 = 0%, p = 0.438); and the mean difference was - 0.84 kg (95% CI - 2.47, 0.80) and - 0.65 kg (95% CI - 1.03, - 0.27) respectively. Participation in control groups of RCTs of lifestyle interventions had a benefit in terms of weight loss in meta-analysis with heterogeneity. These results should be used to interpret the benefits observed with respect to intervention effect in trials. That control groups accrue benefits should be included in patient information sheets to encourage participation in future trials among patients with overweight and obesity.

Project description:BACKGROUND:Postpartum weight retention contributes to long-term weight gain and obesity for many women. Lifestyle interventions with numerous visits are logistically challenging for many postpartum women. Delivering a lifestyle intervention via social media may overcome logistic challenges to participation in in-person weight loss programs. OBJECTIVE:The objective of this study is to conduct a randomized feasibility pilot trial of a 6-month postpartum weight loss intervention delivered via Facebook or in-person groups with 72 postpartum women with overweight or obesity. METHODS:Women with overweight or obesity who are 8 weeks to 12 months postpartum (N=72) will be recruited from the Hartford, Connecticut community. Eligible participants must also own an iPhone or Android smartphone and be an active Facebook user. Participants will receive a 6-month postpartum weight loss intervention based on the Diabetes Prevention Program lifestyle intervention and adapted for postpartum women. Participants will be randomized to receive the intervention via a private Facebook group or in-person group meetings. Assessments will occur at baseline, weekly during the intervention, at 6 months (at the end of the intervention), and at 12 months. Primary feasibility outcomes are recruitment, sustained participation, contamination, retention, and feasibility of assessment procedures including measurement of costs to deliver and receive the intervention. We will describe 6- and 12-month weight loss as an exploratory outcome. RESULTS:Recruitment began in September 2018. The first wave of the intervention began in February 2019, and the second wave of the intervention is expected to begin in fall 2019. We anticipate completing follow-up assessments in fall 2020, and results will be analyzed at that time. CONCLUSIONS:Results will inform the design of a large randomized controlled trial to assess whether delivering a postpartum weight loss intervention via Facebook is noninferior for weight loss and more cost-effective than delivering the intervention via traditional in-person groups. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID):DERR1-10.2196/15530.

Project description:ObjectiveTo assess the effectiveness of a range of weight management programmes in terms of weight loss.DesignEight arm randomised controlled trial.SettingPrimary care trust in Birmingham, England.Participants740 obese or overweight men and women with a comorbid disorder identified from general practice records.InterventionsWeight loss programmes of 12 weeks' duration: Weight Watchers; Slimming World; Rosemary Conley; group based, dietetics led programme; general practice one to one counselling; pharmacy led one to one counselling; choice of any of the six programmes. The comparator group was provided with 12 vouchers enabling free entrance to a local leisure (fitness) centre.Main outcome measuresThe primary outcome was weight loss at programme end (12 weeks). Secondary outcomes were weight loss at one year, self reported physical activity, and percentage weight loss at programme end and one year.ResultsFollow-up data were available for 658 (88.9%) participants at programme end and 522 (70.5%) at one year. All programmes achieved significant weight loss from baseline to programme end (range 1.37 kg (general practice) to 4.43 kg (Weight Watchers)), and all except general practice and pharmacy provision resulted in significant weight loss at one year. At one year, only the Weight Watchers group had significantly greater weight loss than did the comparator group (2.5 (95% confidence interval 0.8 to 4.2) kg greater loss,). The commercial programmes achieved significantly greater weight loss than did the primary care programmes at programme end (mean difference 2.3 (1.3 to 3.4) kg). The primary care programmes were the most costly to provide. Participants allocated to the choice arm did not have better outcomes than those randomly allocated to a programme.ConclusionsCommercially provided weight management services are more effective and cheaper than primary care based services led by specially trained staff, which are ineffective. Trial registration Current Controlled Trials ISRCTN25072883.

Dataset Information

Weight change among people randomized to minimal intervention control groups in weight loss trials.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure