Nonsurgical weight loss interventions: A systematic review of systematic reviews and meta-analyses

Effects of Vertical Sleeve Gastrectomy on Weight Loss, Eating Behaviors, and Weight Concern Eight Months Postsurgery

OBJECTIVES

Following vertical sleeve gastrectomy (VSG), the role of eating behaviors in weight regain remains unclear. This study aimed to examine the effects of VSG on excess weight loss (EWL) and five eating-related variables (food addiction, disinhibition, susceptibility to hunger, dietary restraint, and weight concern) while exploring their associations before and eight months post-surgery.

MATERIALS AND METHODS

A sample of 76 participants who underwent VSG was recruited from a healthcare center in Quebec, Canada. Measurements included body mass index (BMI), the Eating Disorder Examination (weight concern), the Yale Food Addiction Scale (food addiction), and the Three-Factor Eating Questionnaire (disinhibition, susceptibility to hunger, and dietary restraint). T-tests were conducted between pre-surgery (T0) and eight-month post-surgery (T8), and correlations were examined between T0 and T8, within T0, and within T8.

RESULTS

The mean EWL was 63.43% ± 13.14 at T8. Comparisons between T0 and T8 showed a significant decrease in food addiction, disinhibition, and susceptibility to hunger (p = 0.001-0.005). No significant differences were observed for dietary restraint and weight concerns. BMI at T0 was negatively correlated with EWL at T8 (r = -0.45). Within T0, a negative correlation was observed between food addiction and dietary restraint (r = -0.42), which changed from negative to positive within T8 (r = 0.35).

CONCLUSIONS

This study confirmed that VSG is effective for weight loss and associated with a reduction in maladaptive eating behaviors. Postsurgery, individuals with greater food addiction exhibited more dietary restraint, suggesting a need for restraint among those experiencing a strong drive toward food. However, weight concerns remained high even after significant weight loss, indicating that weight loss alone may not be sufficient for change. A postsurgery medical follow-up focusing on overall well-being and lifestyle adaptation would be a crucial complement.

Surgery is associated with better long-term outcomes than pharmacological treatment for obesity: a systematic review and meta-analysis

Obesity is a highly prevalent disease with numerous complications. Both intensive medical treatment with the use of pharmacological drugs and bariatric surgery are current options. The objective of this meta-analysis was to compare, in the long-term, intensive medical treatment and surgery based on twelve parameters related to weight loss, cardiovascular and endocrine changes. A review of the literature was conducted in accordance with the PRISMA guidelines (PROSPERO: CRD42021265637). The literature screening was done from inception to October 2023 through PubMed, EMBASE and Web of Science databases. We included randomized clinical trials that had separate groups for medical treatment and bariatric surgery as an intervention for obesity. The risk of bias was assessed through RoB2. A meta-analysis was performed with measures of heterogeneity and publication bias. Subgroup analysis for each surgery type was performed. Data is presented as forest-plots. Reviewers independently identified 6719 articles and 6 papers with a total 427 patients were included. All studies were randomized controlled trials, three had a follow up of 5 years and two had a follow up of 10 years. Both groups demonstrated statistical significance for most parameters studied. Surgery was superior for weight loss (- 22.05 kg [- 28.86; - 15.23), total cholesterol (- 0.88 [- 1.59; - 0.17]), triglycerides (- 0.70 [- 0.82; - 0.59]), HDL (0.12 [0.02; 0.23]), systolic pressure (- 4.49 [- 7.65; - 1.33]), diastolic pressure (- 2.28 [- 4.25; - 0.31]), Hb glycated (- 0.97 [- 1.31; - 0.62]), HOMA IR (- 2.94; [- 3.52; - 2.35]) and cardiovascular risk (- 0.08; [- 0.10; - 0.05]). Patient in the surgical treatment group had better long term outcomes when compared to the non-surgical group for most clinical parameters.

Experiences of emotional eating in an Acceptance and Commitment Therapy based weight management intervention (SWiM): A qualitative study

BACKGROUND

Emotional eating is a barrier to weight management. Interventions based on Acceptance and Commitment Therapy (ACT) promote the acceptance of uncomfortable feelings, which can reduce the urge to use food as a coping mechanism. We aimed to explore how participants of an ACT-based weight management intervention (WMI) experience emotional eating and relevant intervention content.

METHODS

We conducted semi-structured telephone interviews with participants of a digital ACT-based guided self-help WMI. Fifteen participants were purposefully selected to represent a range of demographic characteristics and emotional eating scores. We used reflexive thematic analysis to explore experiences of emotional eating.

RESULTS

We generated five themes. Participants improved emotional eating by disconnecting emotions from behaviours though increased self-awareness (theme 1) and by implementing alternative coping strategies, including preparation, substitution, and acceptance (theme 2). Most participants maintained improvements in emotional eating over time but wished for more opportunities to re-engage with intervention content, including more immediate support in triggering situations (theme 3). Participants who struggled to engage with emotional eating related intervention content often displayed an external locus of control over emotional eating triggers (theme 4). The perceived usefulness of the intervention depended on participants' prior experiences of emotional eating, and was thought insufficient for participants with complex emotional experiences (theme 5).

DISCUSSION

This ACT-based WMI helped participants with emotional eating by improving self-awareness and teaching alternative coping strategies. Intervention developers may consider adding ongoing forms of intervention that provide both real-time and long-term support. Additionally, a better understanding of how to support people with an external locus of control and people with complex experiences of emotional eating is needed. Future research may explore ways of personalising WMIs based on participants' emotional needs.

Comparative Effectiveness of Cognitive Behavioral Therapy and Behavioral Therapy in Obesity: A Systematic Review and Network Meta-Analysis

We aimed to evaluate the effects of obesity treatment with behavioral therapy (BT) and cognitive behavioral therapy (CBT) interventions compared with multiple comparators and find effective techniques or combinations of techniques in BT and CBT interventions for weight loss. We systematically searched electronic databases and selected randomized controlled trials using CBT or BT intervention for obesity treatment in overweight adults or adults with obesity without psychological symptoms. Both pairwise meta-analysis and network meta-analysis were performed to comprehensively evaluate the comparative effects between interventions. We classified the techniques used in BT and CBT interventions and compared the treatment effects between techniques. Compared with no treatment as a common comparator, CBT was most effective for weight loss, followed by BT, usual care (UC), and minimal care (MC). CBT was a more effective intervention than BT, but the effect of CBT compared to BT was not remarkable in network estimates. The most used BT techniques were feedback and monitoring, and the most used CBT technique was cognitive restructuring. Our results indicated that CBT and BT are effective interventions for weight loss, and that successful weight loss requires more aggressive interventions such as BT or CBT than MC and UC.

The moderating and mediating role of eating behaviour traits in acceptance and commitment therapy-based weight management interventions: protocol for an individual participant data meta-analysis

INTRODUCTION

Precision medicine approaches to obesity aim to maximise treatment effectiveness by matching weight management interventions (WMIs) to characteristics of individuals, such as eating behaviour traits (EBTs). Acceptance and commitment therapy (ACT)-based WMIs may address EBTs such as emotional and uncontrolled eating more effectively than standard interventions, and might be most effective in people with high levels of these traits. However, few studies have examined this directly. We will examine (a) whether ACT-based interventions are more effective for people with certain levels of EBTs (ie, moderation) and (b) whether ACT-based interventions operate through changes in EBTs (ie, mediation).

METHODS AND ANALYSIS

This individual participant data (IPD) meta-analysis will follow the Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Individual Participant Data guidance. We will include studies on ACT-based WMIs that assessed EBTs in people with a body mass index ≥25 kg/m2. We identified studies by screening studies included in a previous review of third wave cognitive behavioural interventions, and updating the search to 20 June 2022. We will request IPD from eligible published and unpublished studies. We will harmonise and re-analyse data using a two-stage random effects meta-analysis pooling within-trial interactions to investigate moderating effects and using a one-stage simultaneous equation model to examine mediating effects. We will assess the risk of bias in included studies using the Cochrane Risk of Bias tool 2 and the Risk of Bias in Non-randomised Studies of Interventions tool.

ETHICS AND DISSEMINATION

Ethical approval has been obtained from the Cambridge Psychology Research Ethics Committee (Application No: PRE.2023.121). Data sharing will follow data transfer agreements and coauthorship will be offered to investigators contributing data. Findings will be disseminated through peer-reviewed journals and conferences and will contribute to the lead author's PhD thesis.

PROSPERO REGISTRATION NUMBER

CRD42022359691.

Weight reduction after bariatric surgery - Do results correlate with postoperative visit frequency?

Background

Consistent follow up after a bariatric surgery is considered vital to adequate and sustained weight reduction. This study examined the strength to which compliance with postsurgical appointments predicted an increase in total body weight loss percent (TBWL%) and change in body mass index (BMI) in a cohort of Illinois based surgical center patients.

Methods

Participants (n = 78) were patients with obesity who underwent bariatric surgery between 2019 and 2021. Patient preoperative weight and BMI, and postoperative weight and BMI at 3-month intervals for one year, and the number of visits were collected from chart review to calculate TBWL%, and change in BMI. Relationship between these factors and postoperative visit compliance were evaluated using linear regression to assess if it was a significant predictor of success.

Results

Follow up visit compliance had a weak positive association with increased TBWL% (Model R2 = 0.134, B = 0.011, p = 0.004) and a minimally stronger association with increased change in BMI (Model R2 = 0.229, B = 0.015, p = 0.0001).

Conclusions

Adherence with follow up visits was weakly related to improved weight reduction outcomes after bariatric surgery. Future investigations should consider how follow up visits can better influence a patient's success in sustaining achieved weight reduction.

The 'Behavioral Balance Model': A new perspective on the aetiology and therapy of obesity

Obesity is a debilitating disease of global proportions that necessitates refined, concept-driven therapeutic approaches. Policy makers, the public and even health care professionals, but also individuals with obesity harbour many misconceptions regarding this disease, which leads to prejudice, negative attitudes, stigmatization, discrimination, self-blame, and failure to provide and finance adequate medical care. Decades of intensive, successful scientific research on obesity have only had a very limited effect on this predicament. We propose a science-based, easy-to-understand conceptual model that synthesizes the complex pathogenesis of obesity including biological, psychological, social, economic and environmental aspects with the aim to explain and communicate better the nature of obesity and currently available therapeutic modalities. According to our integrative 'Behavioral Balance Model', 'top-down cognitive control' strategies are implemented (often with limited success) to counterbalance the increased 'bottom-up drive' to gain weight, which is triggered by biological, psycho-social and environmental mechanisms in people with obesity. Besides offering a deeper understanding of obesity, the model also highlights why there is a strong need for multimodal therapeutic approaches that may not only increase top-down control but also reduce a pathologically increased bottom-up drive.

An exploration of customers' perceptions, preferences, experiences, and feasibility of offering standardized portions in restaurants

Excess caloric intake increases the risk of weight gain, and diet-related chronic diseases. Restaurants play an integral role in the portions of food people consume. Standardization of portion sizes in restaurants can help customers recognize appropriate portions. Through customer interviews, we aimed to assess and understand the feasibility, perceptions, and acceptability of standardized portions in restaurants. Kaiser Permanente partnered with three restaurants in Southern California to create alternative menu options of meals that would not exceed 700 calories. Kaiser Permanente members who lived within a 5-mile radius of the restaurants were informed through email about the study. Customers (N=33), who dined at one of the restaurants participated in a one-on-one semi-structured interview. Interviews were recorded, typed, transcribed verbatim, and analyzed using thematic analysis. Four themes emerged from the analysis: 1) Customers perceive standard portions as a better choice and the benefits outweigh regular portions; 2) Individual and restaurant-related factors may influence portion preferences; 3) Restaurant portions are perceived to be in excess of what customers need; and 4) Portion standardization is an evolving area for restaurants. Our findings suggest positive perceptions and acceptance of standardized portions among restaurant customers. Customer awareness and restaurant standardization procedures can improve customers' dining experience.

The BREAK study protocol: Effects of intermittent energy restriction on adaptive thermogenesis during weight loss and its maintenance

BACKGROUND

Adaptive thermogenesis, defined as the decrease in the energy expenditure components beyond what can be predicted by changes in body mass stores, has been studied as a possible barrier to weight loss and weight maintenance. Intermittent energy restriction (IER), using energy balance refeeds, has been pointed out as a viable strategy to reduce adaptive thermogenesis and improve weight loss efficiency (greater weight loss per unit of energy deficit), as an alternative to a continuous energy restriction (CER). Following a randomized clinical trial design, the BREAK Study aims to compare the effects of IER versus CER on body composition and in adaptive thermogenesis, and understand whether participants will successfully maintain their weight loss after 12 months.

METHODS

Seventy-four women with obesity and inactive (20-45 y) will be randomized to 16 weeks of CER or IER (8x2 weeks of energy restriction interspersed with 7x1 week in energy balance). Both groups will start with 2 weeks in energy balance before energy restriction, followed by 16 weeks in energy restriction, then 8 weeks in energy balance and finally a 12-month weight maintenance phase. Primary outcomes are changes in fat-mass and adaptive thermogenesis after weight loss and weight maintenance. Secondary outcomes include weight loss, fat-free mass preservation, alterations in energy expenditure components, and changes in hormones (thyroid function, insulin, leptin, and cortisol).

DISCUSSION

We anticipate that The BREAK Study will allow us to better understand adaptive thermogenesis during weight loss and weight maintenance, in women with obesity. These findings will enable evidence-based decisions for obesity treatment.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05184361.

Pharmacoeconomic evaluation of anti-obesity drugs for chronic weight management: a systematic review of literature

Introduction

Pharmacological therapy is recommended as a second-line alternative to reverse obesity. Currently, five anti-obesity drugs (AODs) have been approved by the U.S. Food and Drug Administration (FDA) for chronic weight management. The aim of this paper is to investigate the pharmacoeconomic evaluation of AODs through a systematic review with a special focus on methodological considerations.

Methods

We searched the general and specific databases to identify the primary pharmacoeconomic evaluation of AODs.

Results

A total of 18 full-text articles and three conference abstracts were included in this review. Most of the economic assessments were still about Orlistat. And the observations we could make were consistent with the previous systematic review. A few studies were on the combined therapies (i.e. PHEN/TPM ER and NB ER) compared to different comparators, which could hardly lead to a generalized summary of the cost-effectiveness. Most recently, pharmacoeconomic evidence on the newest GLP 1 RA approved for the indication of obesity or obesity with at least one comorbidity emerged gradually. Modelling-based cost-utility analysis is the major type of assessment method. In the modelling studies, a manageable number of the key health states and the state transitions were structured to capture the disease progression. In particular, the principal structure of the decision model adopted in the three studies on the newly approved drug was nearly the same, which enables more in-depth comparisons and generalizations of the findings.

Conclusion

This study provided an up-to-date overview of the strengths and areas for improvement in the methodological design of the pharmacoeconomic evaluation of the licensed drugs for chronic weight management. Future modelling evaluations would benefit from a better understanding of the long-term weight loss effects of the current therapeutic options and the weight rebound process after the discontinuation of treatment.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022302648, identifier CRD42022302648.

Eating disorders in weight-related therapy (EDIT): Protocol for a systematic review with individual participant data meta-analysis of eating disorder risk in behavioural weight management

The Eating Disorders In weight-related Therapy (EDIT) Collaboration brings together data from randomised controlled trials of behavioural weight management interventions to identify individual participant risk factors and intervention strategies that contribute to eating disorder risk. We present a protocol for a systematic review and individual participant data (IPD) meta-analysis which aims to identify participants at risk of developing eating disorders, or related symptoms, during or after weight management interventions conducted in adolescents or adults with overweight or obesity. We systematically searched four databases up to March 2022 and clinical trials registries to May 2022 to identify randomised controlled trials of weight management interventions conducted in adolescents or adults with overweight or obesity that measured eating disorder risk at pre- and post-intervention or follow-up. Authors from eligible trials have been invited to share their deidentified IPD. Two IPD meta-analyses will be conducted. The first IPD meta-analysis aims to examine participant level factors associated with a change in eating disorder scores during and following a weight management intervention. To do this we will examine baseline variables that predict change in eating disorder risk within intervention arms. The second IPD meta-analysis aims to assess whether there are participant level factors that predict whether participation in an intervention is more or less likely than no intervention to lead to a change in eating disorder risk. To do this, we will examine if there are differences in predictors of eating disorder risk between intervention and no-treatment control arms. The primary outcome will be a standardised mean difference in global eating disorder score from baseline to immediately post-intervention and at 6- and 12- months follow-up. Identifying participant level risk factors predicting eating disorder risk will inform screening and monitoring protocols to allow early identification and intervention for those at risk.

What effect have commissioners' policies for body mass index had on hip replacement surgery?: an interrupted time series analysis from the National Joint Registry for England

BACKGROUND

Despite their widespread use, the impact of commissioners' policies for body mass index (BMI) for access to elective surgery is not clear. Policy use varies by locality, and there are concerns that these policies may worsen health inequalities. The aim of this study was to assess the impact of policies for BMI on access to hip replacement surgery in England.

METHODS

A natural experimental study using interrupted time series and difference-in-differences analysis. We used National Joint Registry data for 480,364 patients who had primary hip replacement surgery in England between January 2009 and December 2019. Clinical commissioning group policies introduced before June 2018 to alter access to hip replacement for patients with overweight or obesity were considered the intervention. The main outcome measures were rate of surgery and patient demographics (BMI, index of multiple deprivation, independently funded surgery) over time.

RESULTS

Commissioning localities which introduced a policy had higher surgery rates at baseline than those which did not. Rates of surgery fell after policy introduction, whereas rates rose in localities with no policy. 'Strict' policies mandating a BMI threshold for access to surgery were associated with the sharpest fall in rates (trend change of - 1.39 operations per 100,000 population aged 40 + per quarter-year, 95% confidence interval - 1.81 to - 0.97, P < 0.001). Localities with BMI policies have higher proportions of independently funded surgery and more affluent patients receiving surgery, indicating increasing health inequalities. Policies enforcing extra waiting time before surgery were associated with worsening mean pre-operative symptom scores and rising obesity.

CONCLUSIONS

Commissioners and policymakers should be aware of the counterproductive effects of BMI policies on patient outcomes and inequalities. We recommend that BMI policies involving extra waiting time or mandatory BMI thresholds are no longer used to reduce access to hip replacement surgery.

Effectiveness, persistence of use, and safety of orlistat and liraglutide in a group of patients with obesity

BACKGROUND

To determine the effectiveness, persistence of use, adverse reactions, interactions of orlistat and liraglutide taken for weight loss by a group of obese patients in Colombia.

RESEARCH DESIGN AND METHODS

A retrospective follow-up study of a cohort of patients with obesity treated with orlistat or liraglutide. Sociodemographic, clinical, and pharmacological variables were identified. The effectiveness for weight loss at 12-16 and 52 weeks, persistence of use, and safety were determined.

RESULTS

A total of 294 patients were followed up. At 12-16 weeks after starting orlistat and liraglutide, weight losses of -1.2kg (p=0.002) and -4.1kg (p<0.001) were observed, respectively, and at 52 weeks, reductions of -1.6kg (p=0.208) and -7.8kg (p<0.001) were observed. A total of 8.8% and 31.3% of patients treated with orlistat and liraglutide, respectively, persisted with treatment 1 year after initiation. A total of 17.3% had adverse drug reactions. Older adults with grade II or III obesity who performed physical activity and those treated with liraglutide were more likely to have lost at least 5% of their body weight at 12-16 weeks.

CONCLUSION

Orlistat and liraglutide users presented weight loss at 12-16 weeks. However, this effect was greater and sustained with liraglutide, especially when combined with physical activity.

Spatiotemporal profile of altered neural reactivity to food images in obesity: Reward system is altered automatically and predicts efficacy of weight loss intervention

Introduction

Obesity presents a significant public health problem. Brain plays a central role in etiology and maintenance of obesity. Prior neuroimaging studies have found that individuals with obesity exhibit altered neural responses to images of food within the brain reward system and related brain networks. However, little is known about the dynamics of these neural responses or their relationship to later weight change. In particular, it is unknown if in obesity, the altered reward response to food images emerges early and automatically, or later, in the controlled stage of processing. It also remains unclear if the pretreatment reward system reactivity to food images is predictive of subsequent weight loss intervention outcome.

Methods

In this study, we presented high-calorie and low-calorie food, and nonfood images to individuals with obesity, who were then prescribed lifestyle changes, and matched normal-weight controls, and examined neural reactivity using magnetoencephalography (MEG). We performed whole-brain analysis to explore and characterize large-scale dynamics of brain systems affected in obesity, and tested two specific hypotheses: (1) in obese individuals, the altered reward system reactivity to food images occurs early and automatically, and (2) pretreatment reward system reactivity predicts the outcome of lifestyle weight loss intervention, with reduced activity associated with successful weight loss.

Results

We identified a distributed set of brain regions and their precise temporal dynamics that showed altered response patterns in obesity. Specifically, we found reduced neural reactivity to food images in brain networks of reward and cognitive control, and elevated reactivity in regions of attentional control and visual processing. The hypoactivity in reward system emerged early, in the automatic stage of processing (< 150 ms post-stimulus). Reduced reward and attention responsivity, and elevated neural cognitive control were predictive of weight loss after six months in treatment.

Discussion

In summary, we have identified, for the first time with high temporal resolution, the large-scale dynamics of brain reactivity to food images in obese versus normal-weight individuals, and have confirmed both our hypotheses. These findings have important implications for our understanding of neurocognition and eating behavior in obesity, and can facilitate development of novel integrated treatment strategies, including tailored cognitive-behavioral and pharmacological therapies.

A multicomponent structured health behaviour intervention to improve physical activity in long-distance HGV drivers: the SHIFT cluster RCT

Background

Long-distance heavy goods vehicle drivers are exposed to a multitude of risk factors associated with their occupation. The working environment of heavy goods vehicle drivers provides limited opportunities for a healthy lifestyle, and, consequently, heavy goods vehicle drivers exhibit higher than nationally representative rates of obesity and obesity-related comorbidities, and are underserved in terms of health promotion initiatives.

Objective

The aim of this trial was to test the effectiveness and cost-effectiveness of the multicomponent Structured Health Intervention For Truckers (SHIFT) programme, compared with usual care, at both 6 months and 16–18 months.

Design

A two-arm cluster randomised controlled trial, including a cost-effectiveness analysis and process evaluation.

Setting

Transport depots throughout the Midlands region of the UK.

Participants

Heavy goods vehicle drivers.

Intervention

The 6-month SHIFT programme included a group-based interactive 6-hour education session, health coach support and equipment provision [including a Fitbit® (Fitbit Inc., San Francisco, CA, US) and resistance bands/balls to facilitate a ‘cab workout’]. Clusters were randomised following baseline measurements to either the SHIFT arm or the control arm.

Main outcome measures

Outcome measures were assessed at baseline, with follow-up assessments occurring at both 6 months and 16–18 months. The primary outcome was device-measured physical activity, expressed as mean steps per day, at 6-month follow-up. Secondary outcomes included device-measured sitting, standing, stepping, physical activity and sleep time (on any day, workdays and non-workdays), along with adiposity, biochemical measures, diet, blood pressure, psychophysiological reactivity, cognitive function, functional fitness, mental well-being, musculoskeletal symptoms and work-related psychosocial variables. Cost-effectiveness and process evaluation data were collected.

Results

A total of 382 participants (mean ± standard deviation age: 48.4 ± 9.4 years; mean ± standard deviation body mass index: 30.4 kg/m2 ± 5.1 kg/m2; 99% male) were recruited across 25 clusters. Participants were randomised (at the cluster level) to either the SHIFT arm (12 clusters, n = 183) or the control arm (13 clusters, n = 199). At 6 months, 209 (54.7%) participants provided primary outcome data. Significant differences in mean daily steps were found between arms, with participants in the SHIFT arm accumulating 1008 more steps per day than participants in the control arm (95% confidence interval 145 to 1871 steps; p = 0.022), which was largely driven by the maintenance of physical activity levels in the SHIFT arm and a decline in physical activity levels in the control arm. Favourable differences at 6 months were also seen in the SHIFT arm, relative to the control arm, in time spent sitting, standing and stepping, and time in moderate or vigorous activity. No differences between arms were observed at 16–18 months’ follow-up. No differences were observed between arms in the other secondary outcomes at either follow-up (i.e. 6 months and 16–18 months). The process evaluation demonstrated that the intervention was well received by participants and that the intervention reportedly had a positive impact on their health behaviours. The average total cost of delivering the SHIFT programme was £369.57 per driver, and resulting quality-adjusted life-years were similar across trial arms (SHIFT arm: 1.22, 95% confidence interval 1.19 to 1.25; control arm: 1.25, 95% confidence interval 1.22 to 1.27).

Limitations

A higher (31.4%) than anticipated loss to follow-up was experienced at 6 months, with fewer (54.7%) participants providing valid primary outcome data at 6 months. The COVID-19 pandemic presents a major confounding factor, which limits our ability to draw firm conclusions regarding the sustainability of the SHIFT programme.

Conclusion

The SHIFT programme had a degree of success in positively impacting physical activity levels and reducing sitting time in heavy goods vehicle drivers at 6-months; however, these differences were not maintained at 16–18 months.

Future work

Further work involving stakeholder engagement is needed to refine the content of the programme, based on current findings, followed by the translation of the SHIFT programme into a scalable driver training resource.

Trial registration

This trial is registered as ISRCTN10483894.

Funding

This project was funded by the National Institute for Health and Care Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 10, No. 12. See the NIHR Journals Library website for further project information.

The effectiveness of the Structured Health Intervention For Truckers (SHIFT): a cluster randomised controlled trial (RCT)

BACKGROUND

Long distance heavy goods vehicle (HGV) drivers exhibit higher than nationally representative rates of obesity, and obesity-related co-morbidities, and are underserved in terms of health promotion initiatives. The purpose of this study was to evaluate the effectiveness of the multicomponent 'Structured Health Intervention For Truckers' (SHIFT), compared to usual care, at 6- and 16-18-month follow-up.

METHODS

We conducted a two-arm cluster RCT in transport sites throughout the Midlands, UK. Outcome measures were assessed at baseline, at 6- and 16-18-month follow-up. Clusters were randomised (1:1) following baseline measurements to either the SHIFT arm or usual practice control arm. The 6-month SHIFT programme included a group-based interactive 6-h education and behaviour change session, health coach support and equipment provision (Fitbit® and resistance bands/balls to facilitate a 'cab workout'). The primary outcome was device-assessed physical activity (mean steps/day) at 6 months. Secondary outcomes included the following: device-assessed sitting, physical activity intensity and sleep; cardiometabolic health, diet, mental wellbeing and work-related psychosocial variables. Data were analysed using mixed-effect linear regression models using a complete-case population.

RESULTS

Three hundred eighty-two HGV drivers (mean ± SD age: 48.4 ± 9.4 years, BMI: 30.4 ± 5.1 kg/m², 99% male) were recruited across 25 clusters (sites) and randomised into either the SHIFT (12 clusters, n = 183) or control (13 clusters, n = 199) arms. At 6 months, 209 (55%) participants provided primary outcome data. Significant differences in mean daily steps were found between groups, in favour of the SHIFT arm (adjusted mean difference: 1008 steps/day, 95% CI: 145-1871, p = 0.022). Favourable differences were also seen in the SHIFT group, relative to the control group, in time spent sitting (- 24 mins/day, 95% CI: - 43 to - 6), and moderate-to-vigorous physical activity (6 mins/day, 95% CI: 0.3-11). Differences were not maintained at 16-18 months. No differences were observed between groups in the other secondary outcomes at either follow-up.

CONCLUSIONS

The SHIFT programme led to a potentially clinically meaningful difference in daily steps, between trial arms, at 6 months. Whilst the longer-term impact is unclear, the programme offers potential to be incorporated into driver training courses to promote activity in this at-risk, underserved and hard-to-reach essential occupational group.

TRIAL REGISTRATION

ISRCTN10483894 (date registered: 01/03/2017).

Mendelian randomization suggests a bidirectional, causal relationship between physical inactivity and adiposity

Physical inactivity and increased sedentary time are associated with excess weight gain in observational studies. However, some longitudinal studies indicate reverse causality where weight gain leads to physical inactivity and increased sedentary time. As observational studies suffer from reverse causality, it is challenging to assess the true causal directions. Here, we assess the bidirectional causality between physical inactivity, sedentary time, and adiposity by bidirectional Mendelian randomization analysis. We used results from genome-wide association studies for accelerometer-based physical activity and sedentary time in 91,105 individuals and for body mass index (BMI) in 806,834 individuals. We implemented Mendelian randomization using CAUSE method that accounts for pleiotropy and sample overlap using full genome-wide data. We also applied inverse variance-weighted, MR-Egger, weighted median, and weighted mode methods using genome-wide significant variants only. We found evidence of bidirectional causality between sedentary time and BMI: longer sedentary time was causal for higher BMI [beta (95% CI) from CAUSE method: 0.11 (0.02, 0.2), p = 0.02], and higher BMI was causal for longer sedentary time (0.13 (0.08, 0.17), p = 6.3 x 10^-4). Our analyses suggest that higher moderate and vigorous physical activity are causal for lower BMI (moderate: –0.18 (-0.3,–0.05), p = 0.006; vigorous: –0.16 (-0.24,–0.08), p = 3.8 × 10^-4), but indicate that the association between higher BMI and lower levels of physical activity is due to horizontal pleiotropy. The bidirectional, causal relationship between sedentary time and BMI suggests that decreasing sedentary time is beneficial for weight management, but also that targeting adiposity may lead to additional health benefits by reducing sedentary time.