Describing patterns of weight changes using principal components analysis: results from the Action for Health in Diabetes (Look AHEAD) research group

The effectiveness of social-support-based weight-loss interventions-a systematic review and meta-analysis

OBJECTIVE

This systematic review and meta-analysis examined the effectiveness of social-support-based weight-loss interventions in adult populations with excess weight or obesity.

METHODS

We performed a systematic review of randomized controlled trials that reported on the effectiveness of weight-loss interventions which incorporated a social connectedness component. To this end, we conducted a rigorous database search of MEDLINE, Embase, PsycINFO, CINAHL, Cochrane, and PubMed for relevant articles. The quality of eligible trials was evaluated by the Cochrane Risk-of-Bias2 tool. Five meta-analyses on intervention effectiveness in terms of weight loss were executed at 2-4-month assessment, 6-month assessment, end of intervention, and 3- and 6-month follow-up.

RESULTS

Twenty-four trials involving couples or peers targeting weight loss in 4 919 adults with BMI ≥ 25 met inclusion criteria. Meta-analyses detected no significant effect of social-support-based weight-loss interventions at either 2-4 month or 6-month assessment. There were, however, significant effects at end of intervention [95% CI 0.39, p = 0.04] and at 3-month [95% CI 0.63, p < 0.01] and 6-month [95% CI 0.34, p = 0.05] follow-up.

CONCLUSIONS

There seem to be a significant effect at the end of intervention and 3- and 6-month follow-up. However, further high-quality studies are needed before drawing any clear conclusions.

TRIAL REGISTRATION

PROSPERO 2020 CRD42020173696.

Primary outcomes from Partner2Lose: A randomized controlled trial to evaluate partner involvement on long-term weight loss

Background

Partner support is associated with better weight loss outcomes in observational studies, but randomized trials show mixed results for including partners. Unclear is whether teaching communication skills to couples will improve weight loss in index participants.

Purpose

To compare the efficacy of a partner-assisted intervention versus participant-only weight management program on long-term weight loss.

Methods

This community-based study took place in Madison, WI. Index participants were eligible if they met obesity guideline criteria to receive weight loss counseling, were aged 74 years or younger, lived with a partner, and had no medical contraindications to weight loss; partners were aged 74 years or younger and not underweight. Couples were randomized 1:1 to a partner-assisted or participant-only intervention. Index participants in both arms received an evidence-based weight management program. In the partner-assisted arm, partners attended half of the intervention sessions, and couples were trained in communication skills. The primary outcome was index participant weight at 24 months, assessed by masked personnel; secondary outcomes were 24-month self-reported caloric intake and average daily steps assessed by an activity tracker. General linear mixed models were used to compare group differences in these outcomes following intent-to-treat principles.

Results

Among couples assigned to partner-assisted (n=115) or participant-only intervention (n=116), most index participants identified as female (67%) and non-Hispanic White (87%). Average baseline age was 47.27 years (SD 11.51 years) and weight was 106.55 kg (SD 19.41 kg). The estimated mean 24-month weight loss was similar in the partner-assisted (2.66 kg) and participant-only arms (2.89 kg) (estimated mean difference, 0.23 kg [95% CI, -1.58, 2.04 kg]). There were no differences in 24-month average daily caloric intake (50 cal [95% CI: -233, 132 cal]) or steps (806 steps [95% CI: -1675, 64 steps]). The percentage of participants reporting an adverse event with at least possible attribution to the intervention did not differ by arm (partner-assisted: 9%, participant-only, 3%, p=0.11).

Conclusions

Partner-assisted and individual weight management interventions led to similar outcomes in index participants.

Trial registration

Clinicaltrials.gov NCT03801174.

Precision medicine of obesity as an integral part of type 2 diabetes management - past, present, and future

Obesity is a complex and heterogeneous condition that leads to various metabolic complications, including type 2 diabetes. Unfortunately, for some, treatment options to date for obesity are insufficient, with many people not reaching sustained weight loss or having improvements in metabolic health. In this Review, we discuss advances in the genetics of obesity from the past decade-with emphasis on developments from the past 5 years-with a focus on metabolic consequences, and their potential implications for precision management of the disease. We also provide an overview of the potential role of genetics in guiding weight loss strategies. Finally, we propose a vision for the future of precision obesity management that includes developing an obesity-centred multidisease management algorithm that targets both obesity and its comorbidities. However, further collaborative efforts and research are necessary to fully realise its potential and improve metabolic health outcomes.

Evidence-based weight loss interventions: Individualized treatment options to maximize patient outcomes

Against the backdrop of obesity as a major public health problem, we examined three questions: How much weight loss is needed to benefit patients with obesity? How well do current therapies do in producing weight loss? What strategies can be used to improve patient outcomes using evidence-based studies. This paper reviews literature on the outcomes of lifestyle, diet, medications and surgical treatments for obesity using literature searches for obesity treatments. Current treatments, including lifestyle, diet and exercise, produce a weight loss of 5% to 7% on average. Despite continued attempts to identify superior dietary approaches, most careful comparisons find that low carbohydrate diets are not significantly better than low fat diets for weight loss. The four medications currently approved by the US Food and Drug Administration for long-term management of obesity are not as effective as surgery, adding about 5% on average to lifestyle approaches to weight loss. Two new medications that are under investigation, semaglutide and tirzepatide, significantly improve on this. For all treatments for weight loss, including lifestyle, medications and surgery, there is enormous variability in the amount of weight lost. Examination of this literature has yielded evidence supporting baseline and process predictors, but the effect sizes associated with these predictors are small and there are no prospective studies showing that a personalized approach based on genotype or phenotype will yield uniform success. Because obesity is a chronic disease it requires a 'continuous treatment model' across the lifespan.

Short-term weight trajectories and long-term weight outcomes from a lifestyle intervention in real-world clinical practice

Centers for Disease Control and Prevention aligned lifestyle change programs are effective in promoting weight loss among those with elevated cardiometabolic risk; yet, variability in weight outcomes among participants is high. Little is known about heterogeneity of short-term weight changes among participants in real-world clinical practice. We sought to identify short-term weight trajectory clusters among lifestyle change program participants in real-world clinical practice and to examine the relationship between cluster membership and long-term weight outcomes. We identified participants from the electronic health records (2010-2017) with weight measured ≤30 days prior to program initiation (baseline) and in four intervals (3-week segments) in the 12 weeks after baseline. Clustering analysis was performed to identify distinct trajectories in percent weight change over 12 weeks. Cluster-specific differences in weight change at 12 and 52 weeks were assessed. Among 1,148 participants, across 18 clinic sites, three clusters were identified: minimal-to-no weight loss (MWL), delayed-minimal weight loss (DWL), and steady-moderate weight loss (SWL), corresponding to mean weight changes of 0.4%, -2.3%, and -4.8% at 12 weeks follow-up, respectively. Mean weight changes were 0.4%, -1.8%, and -5.1% for MWL, DWL, and SWL clusters, respectively, at 52 weeks follow-up, which correlated in direction and magnitude with short-term weight changes. Clustering analysis reveals heterogeneous, short-term weight trajectories among lifestyle change program participants in real-world clinical practice. Given the relationship between the magnitudes of short- and long-term weight change, individual participant weight trajectories may be useful in identifying potential non-responders in need of adjunctive or alternative therapy.

In the Footsteps of Wilbur Olin Atwater: The Atwater Lecture for 2019

A central theme of Atwater's research was the development and application of methods to understand how human beings and animals adapt to the nutrients they ingest. The research described in this article also deals with adaptation to nutrition focusing on adaptation to overnutrition, adaptation to undernutrition, adaptation to dietary fat, adaptation to dietary protein, adaptation to micronutrients, and adaptation to sugar and high-fructose corn syrup (HFCS). Studies using overfeeding have shown several things. First, overfeeding did not change the thermic response to ingestion of food nor the coupling of oxidative phosphorylation in muscle to energy expended by muscles during work on a bicycle ergometer between 25 and 100 watts. Second, the response to overfeeding was significantly influenced by the quantity of protein in the diet. During carefully controlled studies of underfeeding of people with obesity, the macronutrient composition of the diet did not affect the magnitude of weight loss. However, baseline genetic and metabolic information could provide guidance for selecting among the lower or higher protein diets, and lower or higher fat diets. Adaptation to an increase in dietary fat from 35% to 50% is slow and variable in healthy sedentary men. Adaptation is more rapid and complete when these same men were physically active. This effect of muscular exercise was traced to changes in the metabolism of glucose in muscles where pathways inhibiting glucose metabolism were activated by exercise. Dietary patterns that increased the intake of calcium, magnesium, and potassium effectively lower blood pressure in individuals with high normal blood pressure. Finally, the intake of sugary beverages was related to the onset of the current epidemic of obesity.

Lessons Learned from the POUNDS Lost Study: Genetic, Metabolic, and Behavioral Factors Affecting Changes in Body Weight, Body Composition, and Cardiometabolic Risk

PURPOSE OF REVIEW

This paper reviews the genetic and non-genetic factors that provided predictions of, or were associated with, weight loss and other metabolic changes in the POUNDS Lost clinical trial of weight loss. This trial randomized 811 individuals who were overweight or obese to one of four diets that contained either 15% or 25% protein and 20% or 40% fat in a 2 × 2 factorial design. A standard behavioral weight loss program was available for all participants who were followed for 2 years with an 80% completion rate.

RECENT FINDINGS

Nineteen genes and five genetic risk scores were used along with demographic, behavioral, endocrine, and metabolic measurements. Genetic variations in most of the genes were associated with weight loss, but this association often varied with the dietary assignment. A number of demographic and behavioral factors, including attendance at behavioral sessions and food cravings were predictive of weight changes. A high baseline level of free triiodothyronine or free thyroxine predicted the magnitude of weight loss. Several perfluoroakyl compounds predicted more rapid weight regain. Genetic evidence from POUNDS Lost provides guidance toward selection of a personalized weight loss diet and improvement in metabolic profile. There is still room for additional research into the predictors of weight loss.

Genetic predictors of weight loss in overweight and obese subjects

The aim of our study was to investigate a large cohort of overweight subjects consuming a homogeneous diet to identify the genetic factors associated with weight loss that could be used as predictive markers in weight loss interventions. We retrospectively recruited subjects (N = 788) aged over 18 years with a Body Mass Index (BMI) between 25 and 40 kg/m² who were treated at our lipid unit for at least one year from 2008 to 2016, and we also recruited a control group (168 patients) with normal BMIs. All participants received counselling from a nutritionist that included healthy diet and physical activity recommendations. We genotyped 25 single nucleotide variants (SNVs) in 25 genes that were previously associated with obesity and calculated genetic scores that were derived from 25 SNVs. The risk allele in CADM2 showed a higher frequency in overweight and obese subjects than in controls (p = 0.007). The mean follow-up duration was 5.58 ± 2.68 years. Subjects with lower genetic scores showed greater weight loss during the follow-up period. The genetic score was the variable that best explained the variations in weight from the baseline. The genetic score explained 2.4% of weight change variance at one year and 1.6% of weight change variance at the end of the follow-up period after adjusting for baseline weight, sex, age and years of follow-up.

The role of partner autonomy support in motivation, well-being, and weight loss among women with higher baseline BMI

INTRODUCTION

The association of partner autonomy support with women's motivation for healthy eating, weight-related health behavior change, and psychological well-being has been largely overlooked. Results of 2 studies showed that the positive association between autonomy support and a variety of motivational and psychological outcomes was especially pronounced for women with high body mass index (BMI) (+1 SD) compared to low BMI (-1 SD).

METHOD

In Study 1, autonomy support was measured as male partners' report of their behavior in a cross-sectional design. In Study 2, autonomy support was measured as female participants' perceptions of their partners' behavior in a longitudinal home environment-based behavioral weight loss intervention.

RESULTS

Study 1 showed that autonomy support from partners was associated with greater self-determined motivation for healthy eating and self-reported well-being among women with higher BMI. Study 2 showed that changes in partner autonomy support over 18 months of a home-based weight loss intervention were associated with increases in motivation for treatment and greater weight loss, especially for women who had higher baseline BMI.

DISCUSSION

Both studies demonstrated that autonomy support was associated with adaptive functioning across weight status but that it was especially potent for women with higher BMI. This pattern of findings is explained in terms of the pressures women with higher BMI may feel about their weight-related behaviors. (PsycINFO Database Record

Two-Year Results of Think Health! ¡Vive Saludable!: A Primary Care Weight-Management Trial

OBJECTIVE

Think Health! ¡Vive Saludable! evaluated a moderate-intensity, lifestyle behavior-change weight-loss program in primary care over 2 years of treatment. Final analyses examined weight-change trajectories by treatment group and attendance.

METHODS

Adult primary care patients (n = 261; 84% female; 65% black; 16% Hispanic) were randomly assigned to Basic Plus (moderate intensity; counseling by primary care clinician and a lifestyle coach) or Basic (clinician counseling only). Intention-to-treat analyses used all available weight measurements from data collection, treatment, and routine clinical visits. Linear mixed-effects regression models adjusted for treatment site, gender, and age, and sensitivity analyses evaluated treatment attendance and the impact of loss to follow-up.

RESULTS

Model-based estimates for 24-month mean (95% CI) weight change from baseline were -1.34 kg (-2.92 to 0.24) in Basic Plus and -1.16 kg (-2.70 to 0.37) in Basic (net difference -0.18 kg [-2.38 to 2.03]; P = 0.874). Larger initial weight loss in Basic Plus was attenuated by a ~0.5-kg rebound at 12 to 16 months. Each additional coaching visit was associated with a 0.37-kg greater estimated 24-month weight loss (P = 0.01).

CONCLUSIONS

These findings in mostly black and Hispanic female primary care patients suggest that strategies to improve treatment attendance may improve weight loss resulting from moderate-intensity counseling.

Prospective associations between diet quality and body mass index in disadvantaged women: the Resilience for Eating and Activity Despite Inequality (READI) study

Background

Dietary patterns that align with recommended guidelines appear to minimize long-term weight gain in the general population. However, prospective associations between diet quality and weight change in disadvantaged adults have not been examined. This study examined associations between concurrent change in diet quality and body mass index (BMI) over 5 years among women living in socioeconomically disadvantaged neighbourhoods.

Methods

Dietary intake and BMI were self-reported among 1242 women living in disadvantaged neighbourhoods in Victoria, Australia, at three time points from 2007/08 to 2012/13. Diet quality was evaluated using the Australian Dietary Guideline Index (DGI). Associations between concurrent change in diet quality and BMI were assessed over the three time points using fixed effects and mixed models. Models were adjusted for age, smoking, menopausal status, education, marital status, number of births, urban/rural location and physical activity.

Results

Average BMI increased by 0.14 kg/m2 per year increase in age in the fixed effects model, and by 0.13 kg/m2 in the mixed model (P < 0.0001). BMI decreased by 0.014 kg/m2 for a woman of average age with each unit increase in DGI score in the fixed effects model (p < 0.0001), and by 0.012 kg/m2 in the mixed model (P = 0.001). The rate of change in BMI with age was greater for those with a lower DGI score than for those with a higher score (P < 0.10).

Conclusions

Positive change in diet quality was associated with reduced BMI gain among disadvantaged women. Supporting disadvantaged women to adhere to population-level dietary recommendations may assist them with long-term weight management.

Accumulating Data to Optimally Predict Obesity Treatment (ADOPT): Recommendations from the Biological Domain

BACKGROUND

The responses to behavioral, pharmacological, or surgical obesity treatments are highly individualized. The Accumulating Data to Optimally Predict obesity Treatment (ADOPT) project provides a framework for how obesity researchers, working collectively, can generate the evidence base needed to guide the development of tailored, and potentially more effective, strategies for obesity treatment.

OBJECTIVES

The objective of the ADOPT biological domain subgroup is to create a list of high-priority biological measures for weight-loss studies that will advance the understanding of individual variability in response to adult obesity treatments. This list includes measures of body composition, energy homeostasis (energy intake and output), brain structure and function, and biomarkers, as well as biobanking procedures, which could feasibly be included in most, if not all, studies of obesity treatment. The recommended high-priority measures are selected to balance needs for sensitivity, specificity, and/or comprehensiveness with feasibility to achieve a commonality of usage and increase the breadth and impact of obesity research.

SIGNIFICANCE

The accumulation of data on key biological factors, along with behavioral, psychosocial, and environmental factors, can generate a more precise description of the interplay and synergy among them and their impact on treatment responses, which can ultimately inform the design and delivery of effective, tailored obesity treatments.

The Science of Obesity Management: An Endocrine Society Scientific Statement

The prevalence of obesity, measured by body mass index, has risen to unacceptable levels in both men and women in the United States and worldwide with resultant hazardous health implications. Genetic, environmental, and behavioral factors influence the development of obesity, and both the general public and health professionals stigmatize those who suffer from the disease. Obesity is associated with and contributes to a shortened life span, type 2 diabetes mellitus, cardiovascular disease, some cancers, kidney disease, obstructive sleep apnea, gout, osteoarthritis, and hepatobiliary disease, among others. Weight loss reduces all of these diseases in a dose-related manner-the more weight lost, the better the outcome. The phenotype of "medically healthy obesity" appears to be a transient state that progresses over time to an unhealthy phenotype, especially in children and adolescents. Weight loss is best achieved by reducing energy intake and increasing energy expenditure. Programs that are effective for weight loss include peer-reviewed and approved lifestyle modification programs, diets, commercial weight-loss programs, exercise programs, medications, and surgery. Over-the-counter herbal preparations that some patients use to treat obesity have limited, if any, data documenting their efficacy or safety, and there are few regulatory requirements. Weight regain is expected in all patients, especially when treatment is discontinued. When making treatment decisions, clinicians should consider body fat distribution and individual health risks in addition to body mass index.

Markers of dietary protein intake are associated with successful weight loss in the POUNDS Lost trial

To assess the association of markers for dietary protein intake, measures of dietary adherence and demographic variables with weight loss in the POUNDS Lost study over the first 6 months and again between 6 and 24 months using data from those who completed each period. This is a secondary analysis of pooled data on completers assigned to one of four diets: 65%C/15%P/20%F (AP/LF), 55%C/25%P/20%F (HP/LF), 45%C/15%P/40%F (AP/HF) or 35%C/25%P40%F (HP/HF) in the POUNDS Lost study. Urinary nitrogen excretion, dietary adherence measured by 24-h recall and attendance at sessions, age (above and below 50 years), gender, race/ethnicity and activity by pedometry were analysed. Increased spread between protein intake at baseline and protein at 6 or 24 months, assessed by urinary nitrogen excretion, was associated with greater weight loss from baseline to 2 years. At 6 and 24 months, older age, male gender, body mass index > 30 kg m-2 and adherence to the fat and protein diets were associated with more weight loss. None of these variables was associated with a regain from 6 to 24 months. Weight regain for women in the highest carbohydrate (65%) group was significantly greater (-4.4 kg [95% CI: -5.9, -3.0]) than for women in the lowest carbohydrate group (-1.8 kg [95% CI: -3.2, -0.4 kg]) (P for interaction = 0.012). An increased spread in the difference between baseline and follow-up protein intake was associated with greater weight loss, consistent with the 'protein spread theory'. Women eating the highest carbohydrate diet regained more weight from 6 to 24 months.

Motivators, Barriers, and Facilitators to Weight Loss and Behavior Change Among African American Adults in Baltimore City: A Qualitative Analysis

BACKGROUND

African American adults achieve smaller amounts of weight loss than their white counterparts when exposed to the same intervention and are more likely to regain weight during long-term follow-up.

OBJECTIVE

To identify perceived motivators, barriers, and facilitators to weight loss and behavior change among African American adults.

METHODS

Two focus groups were conducted between April and May 2015 at an urban community health center in Baltimore City, Maryland. A total of 13 participants took part in the discussions. Eligible participants were obese (BMI 30+) African American adults aged 21-70 who had at least one obesity-related comorbidity. Discussion questions were designed to identify the personal, social, and environmental factors that influence weight loss and behavior change among urban minority populations.

RESULTS

Statements were first classified as a motivator, barrier, or facilitator, then divided further as a personal, social, or environmental factor influencing weight loss and behavior change. Among the findings, several novel motivators (reducing or eliminating medication, improving physical intimacy) and barriers (personal transportation, lack of access to scales) emerged that were not previously characterized in the existing literature.

CONCLUSIONS

This study was intended to provide preliminary evidence that may be used to guide the development of innovative and culturally relevant weight-loss interventions in the future. Results are applicable to similar urban minority populations.

Maintaining a clinical weight loss after intensive lifestyle intervention is the key to cardiometabolic health

OBJECTIVE

Intensive lifestyle interventions (ILI) are criticised for ineffective obesity treatment because weight loss over time is modest and thus of limited clinical relevance. However, a subgroup (5-30%) maintains a clinical weight loss >10%, but it is not clear if cardiometabolic health follows this pattern. The aim was to study the effect of different magnitudes of weight loss maintenance after ILI on cardiometabolic health.

METHODS

Eighty out of 2420 former participants (age: 36±1, BMI: 38±1, (means ±SE)) in an 11-12-week ILI were recruited into 3 groups; clinical weight loss maintenance (>10% weight loss), moderate maintenance (1-10%), and weight regain based on weight loss at follow-up (5.3±0.4years). Weight loss during the ILI was achieved by increased physical activity and hypo-caloric diet. Dual X-ray Absorptiometry, blood sample, skeletal muscle biopsy and VO_2max test were used to determine cardiometabolic health at follow-up.

RESULTS

At follow-up, the clinical weight loss maintenance group scored better in the following variables compared to the other groups: BMI (31±1, 33±2, 43±2kg/m²), composition (34±2, 40±1, 49±1% fat), visceral adipose tissue (0.8±0.2, 1.7±0.5, 2.4±0.4kg), plasma triglycerides (0.8±0.2, 1.3±0.4, 1.6±0.3mmol/L), plasma glucose (4.9±0.1, 5.9±0.4, 5.9±0.1mmol/L), Hb1Ac (5.1±0.0, 5.6±0.2, 5.8±0.2%), protein content in skeletal muscle of GLUT4 (1.5±0.2, 0.9±0.1, 1.0±0.1 AU) and hexokinase II (1.6±0.2, 1.0±0.2, 0.7±0.1 AU), citrate synthase activity (155±6, 130±5, 113±5μmol/g/min) and VO_2max (49±1, 43±1, 41±1mL/min/FFM) (p<0.05).

CONCLUSION

Cardiometabolic health is better in participants who have maintained >10% weight loss compared to moderate weight loss and weight regain.

The Role of Macronutrient Content in the Diet for Weight Management

Diets to treat obesity have been in existence since Hippocrates treated obesity some 2500 years ago. There are currently a wide variety of diets and a common misconception that a single magical diet can cure overweight and obesity. Systematic reviews and meta-analyses indicate that all diets work when adhered to and that initial weight loss can predict the amount of weight lost and maintained for up to 4 years. Individual preferences are thus key in selecting a diet. There are emerging data pinpointing genetic variability in the metabolic responses to variation in macronutrient intake.

FTO genotype and weight loss in diet and lifestyle interventions: a systematic review and meta-analysis

BACKGROUND

Studies have suggested that the fat mass and obesity-associated (FTO) genotype is associated with individual variability in weight loss in response to diet/lifestyle interventions, but results are inconsistent.

OBJECTIVE

We aimed to provide a summary of the literature evaluating the relation between the FTO genotype and weight loss in response to diet/lifestyle interventions.

DESIGN

A search of English-language articles in the PubMed and Embase databases (through 30 April 2015) was performed. Eligible studies were diet/lifestyle weight-loss intervention studies conducted in adults that reported changes in body weight or body mass index (BMI) by the FTO variant rs9939609 (or its proxy). Differences in weight loss between FTO genotypes across studies were pooled with the use of fixed-effect models.

RESULTS

A meta-analysis of 10 studies (comprising 6951 participants) that reported the results of additive genetic models showed that individuals with the FTO TA genotype and AA genotype (those with the obesity-predisposing A allele) had 0.18-kg (95% CI: -0.09-, 0.45-kg;P= 0.19; NS) and 0.44-kg (95% CI: 0.09-, 0.79-kg;P= 0.015) greater weight loss, respectively, than those with the TT genotype. A meta-analysis of 14 studies (comprising 7700 participants) that reported the results of dominant genetic models indicated a 0.20-kg (-0.43-, 0.04-kg) greater weight loss in the TA/AA genotype than in the TT genotype (P= 0.10). In addition, differences in weight loss between the AA genotype and TT genotype were significant in studies with a diet intervention only, adjustment for baseline BMI or body weight, and several other subgroups. However, the relatively small number of studies limited these stratified analyses, and there was no statistically significant difference between subgroups.

CONCLUSIONS

This meta-analysis suggests that individuals carrying the homozygous FTO obesity-predisposing allele may lose more weight through diet/lifestyle interventions than noncarriers. Our data provide evidence for genetic variability in response to diet/lifestyle interventions on weight loss, although clinical applications of these findings need further investigations.

Longitudinal Weight Loss Patterns and their Behavioral and Demographic Associations

BACKGROUND

Identification of weight change patterns may allow tailored interventions to improve long-term weight loss.

PURPOSE

To identify patterns of weight change over 18 months, and assess participant characteristics and intervention adherence factors associated with weight change patterns in a sample of 359 overweight/obese adults.

METHODS

Weight loss (0-6 months) was achieved with reduced energy intake and increased physical activity (PA). Maintenance (7-18 months) provided adequate energy to maintain weight and continued PA.

RESULTS

Latent profile analysis identified three weight change profiles. During weight loss/maintenance, participants in profiles 2 and 3 (18-month weight loss ∼14 %) attended more behavioral sessions and performed more PA compared with profile 1 (18-month weight loss <1 %). Self-efficacy for both weight management and exercise barriers were higher in profiles 2 and 3 compared with profile 1 following weight loss and during maintenance.

CONCLUSION

Weight change patterns can be identified and are associated with both participant characteristics and intervention adherence.

Non-invasive method to analyse the risk of developing diabetic foot

Foot complications (diabetic foot) are among the most serious and costly complications of diabetes mellitus. Amputation of all or part of a lower extremity is usually preceded by a foot ulcer. To prevent diabetic foot, an automatic non-invasive method to identify patients with diabetes who have a high risk of developing diabetic foot is proposed. To design the proposed method, information concerning social scope and self-care of 153 diabetic patients was presented to the K-means clustering algorithm, which divided the data into two groups: high risk and low risk of developing diabetic foot. In the operational stage, the Euclidian distance from the information vector to the centroids of each group of risk is used as criterion for classification. Both real and simulated data were used to evaluate the method in which promising results were achieved with accuracy of 0.97 ± 0.06 for simulated data and 0.68 ± 0.16 considering the classification of specialists as the gold standard for real data. The method requires a simple computational processing and can be useful for basic health units to triage diabetic patients helping the health-care team to reduce the number of cases of diabetic foot.

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.

Baseline characteristics associated with different BMI trajectories in weight loss trials: a case for better targeting of interventions

BACKGROUND/OBJECTIVES

Dietary weight loss interventions have heterogeneous outcomes in long-term studies, with many participants regaining part or all of the lost weight. Growth mixture modelling is a novel analytic approach that can be used to identify different trajectories of weight change during a trial rather than focussing on the total amount of weight lost.

SUBJECTS/METHODS

Data were pooled from two 12-month dietary weight loss studies where no significant difference was detected between the treatment and control arms, thus allowing analysis independent of treatment. The data set included 231 subjects (74.5% female), with a mean weight loss of 6.40 kg (4.96). Growth mixture models were used to identify participants with similar trajectories of change in body mass index (BMI).

RESULTS

Three subgroups were identified. A rapid and continuing BMI loss over the study period (rapid, n=53), a rapid initial weight loss in the first 3 months with a slowing rate over the remaining 9 months (maintainers, n=146) and those with an initial loss trajectory, which slowed and began to increase at 9 months (recidivists, n=53). Age (s.d.) and BMI (s.d.) were significantly different between the three groups (rapid 53 years (7), 28.99 kg/m(2) (3.30); maintainers 47 years (9), 30.90 kg/m(2) (2.95); recidivists 44 years (7), 34.84 kg/m(2) (1.92), both P<0.001).

CONCLUSIONS

Older subjects with lower BMIs were more likely to have a rapid and continuing weight loss in a 1-year dietary-based weight loss intervention. Different interventional approaches may be necessary for different ages and baseline BMIs and stratification prior to randomisation may be necessary to prevent confounding in weight loss trials.

Patterns of weight change in black Americans: pooled analysis from three behavioral weight loss trials

OBJECTIVE

Differentiating trajectories of weight change and identifying associated baseline predictors can provide insights for improving behavioral obesity treatment outcomes.

METHODS

Secondary, observational analyses using growth mixture models were conducted in pooled data for 604 black American, primarily female adults in three completed clinical trials. Covariates of identified patterns were evaluated.

RESULTS

The best fitting model identified three patterns over 2 years: 1) mean weight loss of approximately 2 kg (n = 519); 2) mean weight loss of approximately 3 kg at 1 year, followed by ∼4 kg regain (n = 61); and 3) mean weight loss of ∼20 kg at 1 year followed by ∼4 kg regain (n = 24, with 23 from one study). In final multivariate analyses, higher BMI predicted having pattern 2 (OR [95% CI]) 1.10 [1.03, 1.17]) or 3 (OR [95% CI] 1.42 [1.25, 1.63]), and higher dietary fat score was predictive of a lower odds of having patterns 2 (OR [95% CI] 0.37[0.15, 0.94]) or 3 (OR [95% CI] 0.23 [0.07, 0.79]).

CONCLUSIONS

Findings were consistent with moderate, clinically non-significant weight loss as the predominant pattern across all studies. Results underscore the need to develop novel and more carefully targeted and tailored approaches to facilitating weight loss in black American adults.

Differences in weight loss and health outcomes among African Americans and whites in multicentre trials

The efficacy of behavioural lifestyle interventions (BLI) for weight loss and prevention and treatment of diabetes and hypertension is well established but may vary among racial/ethnic subgroups. This report reviews literature from 1990 to 2012 to determine if outcomes were similar among African Americans (AA) and whites participating in multicentre BLIs funded by the National Institutes of Health. We identified seven relevant trials that reported subgroup analyses for AA. On average, AA lost less weight at 6 months (AA: -1.6 to -7.5 kg; whites: -3.8 to -8.2 kg), but also had less or similar weight regain compared with whites. There were no reported differences between races in diabetes incidence. Three analyses reported no differences in blood pressure; however, a fourth reported that AA women were the only group that did not experience a significant change in blood pressure. Despite increased attention to cultural relevance, race-specific differences in weight loss persist in trials spanning 20 years; however, risk factor modification was similar across race/ethnic groups. Additional research is needed to understand the mechanisms of risk factor modification, and potential for weight change to promote even greater risk factor modification for AA than has been observed to date.

What works for obesity prevention and treatment in black Americans? Research directions

Obesity prevalence in black/African American children and adults of both sexes is high overall and compared with US whites. What we know, and do not know, about how to enhance the effectiveness of obesity prevention and treatment interventions in African Americans is the focus of the 10 articles in this special issue of Obesity Reviews. The evidence base is limited in quantity and quality and insufficient to provide clear guidance. With respect to children, there is relatively consistent, but not definitive support for prioritizing the systematic implementation and evaluation of child-focused interventions in pre-school and school settings and outside of school time. For adults or all ages, developing and refining e-health approaches and faith-based or other culturally and contextually relevant approaches, including translation of the Diabetes Prevention Program intervention to community settings is indicated. Major evidence gaps were identified with respect to interventions with black men and boys, ways to increase participation and retention of black adults in lifestyle behaviour change programmes, and studies of the impact of environmental and policy changes on eating and physical activity in black communities. Bold steps related to research funding priorities, research infrastructure and methodological guidelines are recommended to improve the quantity and quality of research in this domain.

Short-term weight loss patterns, baseline predictors, and longer-term follow-up within a randomized controlled trial

OBJECTIVE

To examine weight loss patterns and predictors among participants in a primary care-based translation study of the Diabetes Prevention Program lifestyle intervention.

DESIGN AND METHODS

Cluster analysis identified short-term (12-week) weight loss patterns among 72 intervention participants. Analysis of variance assessed cluster differences in weight loss maintenance at 15-month follow-up. Discriminant analysis identified baseline characteristics that best differentiated between clusters.

RESULTS

Participants had baseline mean (SD) age of 55.0 (10.8) years and BMI of 31.9 (5.2) kg/m(2) . Cluster analysis identified three short-term weight loss patterns: modest (n = 15; 21%), moderate-and-steady (n = 43; 60%), and substantial-and-early (n = 14; 19%). Only participants with the latter two patterns achieved clinically significant (≥5%) short-term weight loss and maintained it at 15 months. On discriminant analysis, the modest cluster was most differentiated from other clusters by high friend encouragement for dietary change, high obesity-related problems, and low physical well-being. The moderate-and-steady cluster was differentiated by lower physical activity, family encouragement, and depression symptoms.

CONCLUSION

Results provided insight into the heterogeneity of response to an effective lifestyle intervention by identifying short-term weight loss patterns and their baseline predictors and relationship to 15-month success. If replicated, results may help tailor strategies for participant subgroups in weight loss programs.

Improving discrimination in the grading of rat mammary tumors using two-dimensional mapping of histopathological observations

This work aims at characterizing rat mammary tumors induced by 7,12-dimethylbenz(a)anthracene (DMBA) and the respective malignancy potential, commonly graded with histopathology features grouped by intensity levels. Tumors were described over fourteen multiple ranged microscopic parameters and a comprehensive characterization of the histological patterns and their relation with tumor grade was carried out by principal component analysis (PCA). The number of histological patterns present on a tumor tends to correlate with malignant features. High grade tumors are characterized by the presence of several structural patterns, with cribriform prevalence and necrosis. The cribriform pattern correlates with grading, i.e., tumors having a higher predominance of the cribriform pattern are likely to be more malignant. The findings may represent a benchmark for similar characterization studies in other models.

Patterns of weight change associated with long-term weight change and cardiovascular disease risk factors in the Look AHEAD Study

This article provides an assessment of the associations that weight-loss patterns during the first year of an intensive lifestyle intervention have with 4-year maintenance and health outcomes. Two components described patterns of weight change during the first year of intervention: one reflected the typical pattern of weight loss over the 12 months, but distinguished those who lost larger amounts across the monthly intervals from those who lost less. The second component reflected the weight change trajectory, and distinguished a pattern of initial weight loss followed by regain vs. a more sustained pattern of weight loss. Two thousand four hundred and thirty eight individuals aged 45-76 years with type 2 diabetes mellitus, who enrolled in the weight-loss intervention of a randomized clinical trial, were assigned scores according to how their weight losses reflected these patterns. Relationships these scores had with weight losses and health outcomes (glycosolated hemoglobin--hemoglobin A1c (HbA1c); systolic blood pressure, high-density lipoprotein (HDL)-cholesterol, and triglycerides) over 4 years were described. When compared to those with lower scores on the two components, both individuals who had larger month-to-month weight losses in year 1 and whose weight loss was more sustained during the first year had better maintenance of weight loss over 4 years, independent of characteristics traditionally linked to weight loss success (P < 0.001). While relationships with year 4 weight loss were stronger, the pattern of larger monthly weight loss during year 1 was also independently predictive of year 4 levels of HbA1c, HDL-cholesterol, and systolic blood pressure.

Randomized controlled trial of a comprehensive home environment-focused weight-loss program for adults

OBJECTIVE

Behavioral weight-loss programs (BWL) provide limited instruction on how to change the environmental context of weight-regulating behaviors, perhaps contributing to regain. Drawing on social ecological models, this trial evaluated a comprehensive weight-loss program that targeted both an individual's behavior and his or her physical and social home environment.

METHOD

Overweight and obese adults (N = 201; 48.9 ± 10.5 years; 78.1% women) were randomized to BWL or to BWL plus home-environment changes (BWL + H). Groups met weekly for 6 months and bimonthly for 12 months. BWL + H participants were given items to facilitate healthy choices in their homes (e.g., exercise equipment, portion plates) and attended treatment with a household partner. Weight loss at 6 and 18 months was the primary outcome.

RESULTS

BWL + H changed many aspects of the home environment and produced better 6-month weight losses than BWL (p = .017). At 18 months, no weight-loss differences were observed (p = .19) and rates of regain were equivalent (p = .30). Treatment response was moderated by gender (6 months, p = .011; 18 months, p = .006). Women lost more weight in BWL + H than BWL at 6 and 18 months, whereas men in BWL lost more weight than those in BWL + H at 18 months. Partners, regardless of gender, lost more weight in BWL + H than BWL at both time points (ps < .0001).

CONCLUSION

The home food and exercise environment is malleable and targeting this microenvironment appears to improve initial weight loss, and in women, 18-month outcomes. Research is needed to understand this gender difference and to develop home-focused strategies with more powerful and sustained weight-loss effects.

Correlates of weight patterns during middle age characterized by functional principal components analysis

PURPOSE

Describing weight trajectories using functional methods may further our understanding of how weight impacts health. We characterize weight patterns and describe correlates of these patterns.

METHODS

Using a subset of the Framingham Heart Study original cohort limited-access data set (n=1,429), we conducted a functional principal components analysis (PCA) of body mass index from 40 to 55 years of age. Scores from the principal component functions defined weight patterns. Gender-specific logistic regression models provided estimates of association with sociodemographic and lifestyle factors.

RESULTS

Overall weight status, weight changes, and cycling emerged as weight patterns during middle age. Overweight/obesity at 25 years was the most consistent correlate of weight patterns (adjusted odds ratios [AORs] for men and women were 14.2 and 3.7 for overall overweight, 99.5 and 28.3 for overall obese, and 1.4 and 3.9 for cycling). Weight status at 25 years was not associated with weight gain in either gender or weight loss in men; for women the AOR was 2.7 for weight loss.

CONCLUSIONS

Functional PCA described weight patterns during middle age. The strong associations between weight status at 25 years and overall weight status and cycling during middle age underscore the importance of addressing weight earlier in life.