Effects of age, sex, and treatment on weight-loss dynamics in overweight people

Socio-Demographic and Preoperative Clinical Factors Associated With 5-Year Weight Trajectories After Roux-en-Y Gastric Bypass and Sleeve Gastrectomy

Objective

To determine whether socio-demographic and preoperative clinical factors contribute to the percent total body weight loss (%TBWL) after bariatric surgery (BS).

Background

BS is the most effective long-term treatment for medically complicated obesity. More information is needed about the factors that contribute to postoperative %TBWL in large and ethnically diverse cohorts.

Methods

This retrospective study conducted in the Kaiser Permanente Northern California region included 7698 patients who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) between January 2009 and March 2015. Trajectory analyses were conducted from 5-year follow-up data to assign patients to "low," "average," or "high" postoperative %TBWL groups. We then evaluated whether age, sex, race/ethnicity, neighborhood deprivation index and preoperative body mass index (BMI)/weight loss, diabetes, hypertension, and sleep apnea contributed to postoperative %TBWL using logistic regression models.

Results

Of 7698 patients (83.2% women), 48.6% underwent a RYGB and 51.4% underwent a SG. Postoperative %TBWL trajectories over 5 years were obtained in 6229 (81%) of 7698 eligible patients. About 27.8% and 29.3% of patients followed the "low" postoperative %TBWL trajectory, for RYGB and SG, respectively. Men, older patients, and Asian, Black, and Hispanic/Latino patients were more likely to be classified in the low postoperative %TBWL group. Patients showing lower postoperative %TBWL had a lower preoperative BMI (but lost less weight before surgery) and were more likely to have preoperative comorbidities.

Conclusions

This study confirms and extends prior findings of the effects of several demographic and preoperative clinical factors on postoperative weight loss. Findings could improve the support of patients to achieve desired surgical outcomes.

Plasma Concentration of 36 (Poly)phenols and Prospective Body Weight Change in Participants from the EPIC Cohort

INTRODUCTION

Dietary intake of (poly)phenols has been linked to reduced adiposity and body weight (BW) in several epidemiological studies. However, epidemiological evidence on (poly)phenol biomarkers, particularly plasma concentrations, is scarce. We aimed to investigate the associations between plasma (poly)phenols and prospective BW change in participants from the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort.

METHODS

This study included 761 participants with data on BW at baseline and after 5 years of follow-up. Plasma concentrations of 36 (poly)phenols were measured at baseline using liquid chromatography-tandem mass spectrometry. Associations were assessed through general linear mixed models and multinomial logistic regression models, using change in BW as a continuous or as a categorical variable (BW loss, maintenance, gain), respectively. Plasma (poly)phenols were assessed as log2-transformed continuous variables. The false discovery rate (FDR) was used to control for multiple comparisons.

RESULTS

Doubling plasma (poly)phenol concentrations showed a borderline trend towards a positive association with BW loss. Plasma vanillic acid showed the strongest association (-0.53 kg/5 years; 95% confidence interval [CI]: -0.99, -0.07). Similar results were observed for plasma naringenin comparing BW loss versus BW maintenance (odds ratio: 1.1; 95% CI: 1.0, 1.2). These results did not remain significant after FDR correction.

CONCLUSION

Higher concentrations of plasma (poly)phenols suggested a tendency towards 5-year BW maintenance or loss. While certain associations seemed promising, they did not withstand FDR correction, indicating the need for caution in interpreting these results. Further studies using (poly)phenol biomarkers are needed to confirm these suggestive protective trends.

Additional Effects of Reduced Emotional Eating on Associations of Weight Loss via Changes in Social Cognitive Theory Variables

BACKGROUND

Improvements in the theory-based psychosocial variables of eating self-regulation, mood, and self-efficacy for controlled eating significantly predicted weight loss in community-based obesity treatments. However, in women, additional effects from reductions in emotional eating, and age and race/ethnicity are unclear.

METHODS

Women (N = 130) participating in a community-based cognitive-behavioral obesity treatment were assessed on changes in theory-based psychosocial variables and weight.

RESULTS

Treatment-associated improvements in self-regulation, mood, and self-efficacy over 3 months significantly predicted 6-month weight loss (R² = 0.26), with self-regulation change being the strongest individual predictor. Entry of change in emotional eating into the prediction model significantly added to the variance in weight change explained. Age and race/ethnicity did not further improve the predictive strength.

CONCLUSIONS

In addition to targeting self-regulation skill development and, to a lesser extent addressing mood and self-efficacy improvements, behavioral obesity treatments should focus on emotional eating to maximize their large-scale effects on excess weight.

Body Composition Changes after a Weight Loss Intervention: A 3-Year Follow-Up Study

Studies comparing different types of exercise-based interventions have not shown a consistent effect of training on long-term weight maintenance. The aim of this study was to compare the effects of exercise modalities combined with diet intervention on body composition immediately after intervention and at 3 years’ follow-up in overweight and obese adults. Two-hundred thirty-nine people (107 men) participated in a 6-month diet and exercise-based intervention, split into four randomly assigned groups: strength group (S), endurance group (E), combined strength and endurance group (SE), and control group (C). The body composition measurements took place on the first week before the start of training and after 22 weeks of training. In addition, a third measurement took place 3 years after the intervention period. A significant interaction effect (group × time) (p = 0.017) was observed for the fat mass percentage. It significantly decreased by 5.48 ± 0.65%, 5.30 ± 0.65%, 7.04 ± 0.72%, and 4.86 ± 0.65% at post-intervention for S, E, SE, and C, respectively. Three years after the intervention, the fat mass percentage returned to values similar to the baseline, except for the combined strength and endurance group, where it remained lower than the value at pre-intervention (p < 0.05). However, no significant interaction was discovered for the rest of the studied outcomes, neither at post-intervention nor 3 years later. The combined strength and endurance group was the only group that achieved lower levels of fat mass (%) at both post-intervention and 3 years after intervention, in comparison with the other groups.

Development and validation of prognostic models to estimate body weight loss in overweight and obese people

Introduction

Background: predicting weight loss outcomes from information collected from subjects before they start a weight management program is an objective strongly pursued by scientists who study energy balance. Objective: to develop and validate two prognostic models for the estimation of final body weight after a six-month intervention period. Material and methods: the present work was developed following the TRIPOD standard to report prognostic multivariable prediction models. A multivariable linear regression analysis was applied to 70 % of participants to identify the most relevant variables and develop the best prognostic model for body weight estimation. Then, 30 % of the remaining sample was used to validate the model. The study involved a 6-month intervention based on 25-30 % caloric restriction and exercise. A total of 239 volunteers who had participated in the PRONAF study, aged 18 to 50 years, with overweight or obesity (body mass index: 25-34.9 kg/m2), were enrolled. Body composition was estimated by dual-energy X-ray absorptiometry (DXA) and by hand-to-foot bioelectrical impedance (BIA) analysis. Results: prognostic models were developed and validated with a high correlation (0.954 and 0.951 for DXA and BIA, respectively), with the paired t-tests showing no significant differences between estimated and measured body weights. The mean difference, standard error, and 95 % confidence interval of the DXA model were 0.067 ± 0.547 (-1.036-1.170), and those of the BIA model were -0.105 ± 0.511 (-1.134-0.924). Conclusions: the models developed in this work make it possible to calculate the final BW of any participant engaged in an intervention like the one employed in this study based only on baseline body composition variables.

Polygenic risk score for predicting weight loss after bariatric surgery

BACKGROUND

The extent of weight loss among patients undergoing bariatric surgery is highly variable. Herein, we tested the contribution of genetic background to such interindividual variability after biliopancreatic diversion with duodenal switch.

METHODS

Percentage of excess body weight loss (%EBWL) was monitored in 865 patients over a period of 48 months after bariatric surgery, and two polygenic risk scores were constructed with 186 and 11 (PRS186 and PRS11) single nucleotide polymorphisms previously associated with body mass index (BMI).

RESULTS

The accuracy of the %EBWL logistic prediction model - including initial BMI, age, sex, and surgery modality, and assessed as the area under the receiver operating characteristics (ROC) curve adjusted for optimism (AUCadj = 0.867) - significantly increased after the inclusion of PRS186 (ΔAUCadj = 0.021; 95% CI of the difference [95% CIdiff] = 0.005-0.038) but not PRS11 (ΔAUCadj= 0.008; 95% CIdiff= -0.003-0.019). The overall fit of the longitudinal linear mixed model for %EBWL showed a significant increase after addition of PRS186 (-2 log-likelihood = 12.3; P = 0.002) and PRS11 (-2 log-likelihood = 9.9; P = 0.007). A significant interaction with postsurgery time was found for PRS186 (β = -0.003; P = 0.008) and PRS11 (β = -0.008; P = 0.03). The inclusion of PRS186 and PRS11 in the model improved the cost-effectiveness of bariatric surgery by reducing the percentage of false negatives from 20.4% to 10.9% and 10.2%, respectively.

CONCLUSION

These results revealed that genetic background has a significant impact on weight loss after biliopancreatic diversion with duodenal switch. Likewise, the improvement in weight loss prediction after addition of polygenic risk scores is cost-effective, suggesting that genetic testing could potentially be used in the presurgical assessment of patients with severe obesity.

FUNDING

Heart and Stroke Foundation of Canada (G-17-0016627) and Canada Research Chair in Genomics Applied to Nutrition and Metabolic Health (no. 950-231-580).

What is the most effective exercise protocol to improve cardiovascular fitness in overweight and obese subjects?

BACKGROUND

Increased peak oxygen consumption (VO_2peak) can reduce cardiovascular risks associated with obesity. Our aim was to analyze the effect of a weight loss program on cardiovascular fitness in overweight (W) and obese (O) subjects.

METHODS

One hundred and sixty-seven subjects (77 males and 90 females), aged 18-50 years, performed a modified Bruce protocol before (pre) and after (post) a weight loss program of 24 weeks. This program combined physical training (strength, S; endurance, E; combined strength + endurance, SE; or physical activity recommendation, PA) 3 times per week, with a 25%-30% caloric restriction diet.

RESULTS

VO_2peak improved in overweight and obese males (pre and post values in L/min, respectively; W = 3.2 ± 0.6 vs. 3.7 ± 0.5, p < 0.001; O = 3.6 ± 0.6 vs. 3.8 ± 0.6, p = 0.013) as well as in overweight females (2.0 ± 0.3 vs. 2.3 ± 0.4, p < 0.001). VO_2peak in the first ventilatory threshold (VT₁) increased for all 4 interventions in males (p < 0.05), except for S in the obese group (1.6 ± 0.2 vs. 1.7 ± 0.3, p = 0.141). In females, it increased in E (0.9 ± 0.2 vs. 1.4 ± 0.3, p < 0.001), SE (0.9 ± 0.2 vs. 1.2 ± 0.4, p = 0.003), and PA (0.9 ± 0.1 vs. 1.2 ± 0.2, p = 0.006) in overweight groups. Time-to-exhaustion improved in all subjects except for females in PA group (15.7 ± 0.3 min vs. 15.9 ± 0.3 min, p = 0.495).

CONCLUSION

Our results suggest that all methods, including the recommendation of physical activity, can improve cardiovascular fitness in overweight subjects and obese males.

A Multidisciplinary Approach to Treating Obesity in a Community Health Centre

OBJECTIVES

The aim of the study is to assess the weight loss programme with regards to the long-term effectiveness of weight reduction and weight maintenance, using completion rate and BMI, blood sugar, cholesterol and blood pressure levels as outcomes. The aim of the study also includes identifying the factors associated with adherence to the programme.

METHODS

The programme was developed by a multidisciplinary team. It included 6 months of introduction and another 18 months of maintenance. The data for 397 participants was collected after 24 months.

RESULTS

346 participants have completed the introduction and 123 have completed the programme. In the introduction, the average weight loss was 12% of the initial weight. The participants, who completed the full programme, lost 9.4% of their initial weight. The participants also significantly (p<0.05) reduced their blood sugar and cholesterol levels, as well as their blood pressure. The factors associated with adherence to the programme are: age over 50, lower educational levels, lower initial weight and higher weight loss in the introduction.

CONCLUSIONS

The multi-disciplinary approach to obesity treatment was effective for a selected group of people. The proportion of dropouts was relatively high, but still low compared to similar programmes. Group treatment and mutual support are of a great importance in bringing about and maintaining the changes.

The Impact of Gender and Protein Intake on the Success of Weight Maintenance and Associated Cardiovascular Risk Benefits, Independent of the Mode of Food Provision: The DiOGenes Randomized Trial

OBJECTIVE

Maintenance of weight loss and associated cardiovascular benefits after following energy-restricted diets is still a challenging field, and thorough investigation is needed. The present research aimed to determine the role of protein and gender in relation to two different intervention models related to food supply, in a weight maintenance trial.

SUBJECTS AND METHODS

The DiOGenes trial was a long-term, multicenter, randomized, dietary intervention study, conducted in eight European countries (Clinical Trials.gov, NCT00390637), focusing on assessing the effectiveness of weight maintenance over 6 months. This secondary analysis intended to evaluate the different benefits for weight maintenance and cardiometabolic markers of two dietary advice delivery models: "shop + instruction intervention" vs "instruction-alone intervention," which were further categorized for gender and macronutrient intake.

RESULTS

The weight maintenance intervention based on different macronutrient intake showed, independently of the advice delivery model, in both sexes that higher protein consumption was more effective for weight stability, showing better results in obese women (low protein: 1.65 kg in males and 0.73 Kg in females vs high protein: 1.45 kg in males and -0.93 Kg in females) . Measurements concerning cardiovascular risk markers from subjects on both structured models produced similar trends in the subsequent follow-up period, with a lower rebound in women for most of the markers analyzed.

CONCLUSION

The reported dietary benefits for weight sustainability should be ascribed to the macronutrient distribution (higher protein diets) rather than to the structured mode of delivery. Higher weight regain in males was noted, as well as a metabolic divergence attributable to the sex, with a better biochemical outcome in women.