Effects of the Norfolk diabetes prevention lifestyle intervention (NDPS) on glycaemic control in screen-detected type 2 diabetes: a randomised controlled trial.

BACKGROUND: The purpose of this trial was to test if the Norfolk Diabetes Prevention Study (NDPS) lifestyle intervention, recently shown to reduce the incidence of type 2 diabetes in high-risk groups, also improved glycaemic control in people with newly diagnosed screen-detected type 2 diabetes. METHODS: We screened 12,778 participants at high risk of type 2 diabetes using a fasting plasma glucose and glycosylated haemoglobin (HbA1c). People with screen-detected type 2 diabetes were randomised in a parallel, three-arm, controlled trial with up to 46 months of follow-up, with a control arm (CON), a group-based lifestyle intervention of 6 core and up to 15 maintenance sessions (INT), or the same intervention with additional support from volunteers with type 2 diabetes trained to co-deliver the lifestyle intervention (INT-DPM). The pre-specified primary end point was mean HbA1c compared between groups at 12 months. RESULTS: We randomised 432 participants (CON 149; INT 142; INT-DPM 141) with a mean (SD) age of 63.5 (10.0) years, body mass index (BMI) of 32.4 (6.4) kg/m2, and HbA1c of 52.5 (10.2) mmol/mol. The primary outcome of mean HbA1c at 12 months (CON 48.5 (9.1) mmol/mol, INT 46.5 (8.1) mmol/mol, and INT-DPM 45.6 (6.0) mmol/mol) was significantly lower in the INT-DPM arm compared to CON (adjusted difference -2.57 mmol/mol; 95% CI -4.5, -0.6; p = 0.007) but not significantly different between the INT-DPM and INT arms (-0.55 mmol/mol; 95% CI -2.46, 1.35; p = 0.57), or INT vs CON arms (-2.14 mmol/mol; 95% CI -4.33, 0.05; p = 0.07). Subgroup analyses showed the intervention had greater effect in participants < 65 years old (difference in mean HbA1c compared to CON -4.76 mmol/mol; 95% CI -7.75, -1.78 mmol/mol) than in older participants (-0.46 mmol/mol; 95% CI -2.67, 1.75; interaction p = 0.02). This effect was most significant in the INT-DPM arm (-6.01 mmol/mol; 95% CI -9.56, -2.46 age < 65 years old and -0.22 mmol/mol; 95% CI -2.7, 2.25; aged > 65 years old; p = 0.007). The use of oral hypoglycaemic medication was associated with a significantly lower mean HbA1c but only within the INT-DPM arm compared to CON (-7.0 mmol/mol; 95% CI -11.5, -2.5; p = 0.003). CONCLUSION: The NDPS lifestyle intervention significantly improved glycaemic control after 12 months in people with screen-detected type 2 diabetes when supported by trained peer mentors with type 2 diabetes, particularly those receiving oral hypoglycaemics and those under 65 years old. The effect size was modest, however, and not sustained at 24 months. TRIAL REGISTRATION: ISRCTN34805606 . Retrospectively registered 14.4.16.

Intervention fidelity assessment: A sub-study of the Norfolk Diabetes Prevention Study (NDPS).

BACKGROUND: Previous research has shown that lifestyle modification can delay or prevent the onset of type 2 diabetes in high-risk individuals. The Norfolk Diabetes Prevention Study (NDPS) was a parallel, three-arm, randomized controlled trial with up to 46 months follow-up that tested a group-delivered, theory-based lifestyle intervention to reduce the incidence of type 2 diabetes in high-risk groups. The current study aimed to evaluate if the NDPS intervention was delivered to an acceptable standard and if any part(s) of the delivery required improvement. METHODS: A sub-sample of 30, 25 for inter-rater reliability and audio-recordings of the NDPS intervention education sessions were assessed independently by two reviewers (CT, TW) using a 12-item checklist. Each item was scored on a 0-5 scale, with a score of 3 being defined as 'adequate delivery'. Inter-rater reliability was assessed. Analysis of covariance (ANCOVA) was used to assess changes in intervention fidelity as the facilitators gained experience. RESULTS: Inter-rater agreement was acceptable (86%). A mean score of 3.47 (SD = .38) was achieved across all items of the fidelity checklist and across all intervention facilitators (n = 6). There was an apparent trend for intervention fidelity scores to decrease with experience; however, this trend was non-significant (p > .05) across all domains in this small sample. CONCLUSION: The NDPS was delivered to an acceptable standard by all Diabetes Prevention Facilitators. Further research is needed to better understand how the intervention's delivery characteristics can be optimized and how they might vary over time.

Trained Volunteers With Type 2 Diabetes Experience Significant Health Benefits When Providing Peer Support.

Trained lay volunteers may have value in supporting lifestyle change programs in the prevention of type 2 diabetes, but the potential health benefits (or harms) experienced by these lay volunteers have not been well described. This is important, as this is an appealing model in terms of workforce planning. The aim of the prespecified quantitative study reported here, was to examine the possible health benefits or harms experienced by these trained lay volunteers with type 2 diabetes. In a large type 2 diabetes prevention program, we recruited and trained 104 lay volunteers with type 2 diabetes themselves, to act as diabetes prevention mentors and codeliver the lifestyle intervention. Mentors made motivational telephone calls to 461 participants randomized to one of the trial arms to encourage lifestyle changes. Weight, diet, physical activity, well-being, quality of life, diabetes-specific self-efficacy, and glycaemic control were measured at baseline, 12 and 24 months. Average mentor age was 62.0 years, 57 (54.8%) were male, 92 (88.5%) were overweight or obese (BMI>30 kg/m2). At 12 months, mentor dietary behaviors (fat and fiber intake) improved significantly, sedentary time spent fell significantly, and diabetes specific self-efficacy scores significantly increased. These significant improvements, with no evidence of harms, suggest lay volunteers with type 2 diabetes codelivering a lifestyle intervention, may themselves experience health benefits from volunteering.

Quantity and specificity of action-plans as predictors of weight loss: analysis of data from the Norfolk Diabetes Prevention Study (NDPS).

OBJECTIVE: Investigate associations between quantity, content and specificity of action-plans and weight loss in a diabetes prevention study. DESIGN: Prospective cohort study nested within a randomised controlled trial. Participants completed action-planning worksheets during intervention sessions. MAIN OUTCOME MEASURES: Action-plans were coded in terms of: number of plans set, their content, and specificity. Multivariate regression analyses assessed associations with weight loss at four-months. RESULTS: 890 planning-worksheets from 106 participants were analysed. Participants wrote a mean of 2.12 (SD = 1.20) action-plans per worksheet, using a mean of 2.20 (SD = 0.68) specificity components per action-plan. Quantity of action-plans per worksheet decreased over time (r = -0.137, p < 0.001) and increased quantity was associated with reduced specificity [r = -.215, p < 0.001]. Walking (34.9% of action-plans) and reducing high fat/sugar snacks (26.1%) were the most commonly planned lifestyle actions. In multivariate modelling, increased quantity of action-plans was associated with greater weight loss (R2 = 0.135, Unstandardised Beta = 0.144, p = 0.002). Specificity was not significantly associated with weight-loss (p = 0.096). CONCLUSION: Producing more action-plans was associated with greater weight loss. Further research should directly compare more versus less specific action-plans and explore ways to sustain engagement in action-planning. Our findings imply that participants should freely set numerous action-plans, rather than being encouraged to focus on specificity.Supplemental data for this article is available online at https://doi.org/10.1080/08870446.2022.2055026 .

Feasibility and acceptability of a multi-domain intervention to increase Mediterranean diet adherence and physical activity in older UK adults at risk of dementia: protocol for the MedEx-UK randomised controlled trial.

INTRODUCTION: Dementia prevalence continues to increase, and effective interventions are needed to prevent, delay or slow its progression. Higher adherence to the Mediterranean diet (MedDiet) and increased physical activity (PA) have been proposed as strategies to facilitate healthy brain ageing and reduce dementia risk. However, to date, there have been no dementia prevention trials in the UK focussed on combined dietary and PA interventions. This study aims to: (1) assess feasibility and acceptability of a theory-underpinned digital and group-based intervention for dementia risk reduction in an 'at risk' UK cohort; (2) evaluate behaviour change responses to the intervention; and, (3) provide information on cognitive, neurological, vascular and physiological outcomes to inform the design of a follow-on, full-scale efficacy trial. METHODS: One hundred and eight participants aged 55 to 74 years with a QRISK2 score of ≥10% will be recruited to take part in this 24-week multi-site study. Participants will be randomised into three parallel arms: (1) Control; (2) MedDiet; and, (3) MedDiet+PA. The study will evaluate a personalised website, group session and food delivery intervention to increase MedDiet adherence and PA in older adults at risk of dementia. Diet and PA will be monitored prior to, during and following the intervention. Feasibility, acceptability and hypothesised mediators will be assessed in addition to measures of cognitive function, brain structure/perfusion (MRI), vascular function and metabolic markers (blood, urine and faecal) prior to, and following, the intervention. DISCUSSION: This trial will provide insights into the feasibility, acceptability and mechanism of effect of a multi-domain intervention focussed on the MedDiet alone and PA for dementia risk reduction in an 'at risk' UK cohort. ETHICS AND DISSEMINATION: The study has received NHS REC and HRA approval (18/NI/0191). Findings will be disseminated via conference presentations, public lectures, and peer-reviewed publications. TRIAL REGISTRATION DETAILS: ClinicalTrials.gov NCT03673722.

Lifestyle Intervention With or Without Lay Volunteers to Prevent Type 2 Diabetes in People With Impaired Fasting Glucose and/or Nondiabetic Hyperglycemia: A Randomized Clinical Trial.

Importance: Nearly half of the older adult population has diabetes or a high-risk intermediate glycemic category, but we still lack trial evidence for effective type 2 diabetes prevention interventions in most of the current high-risk glycemic categories. Objective: To determine whether a group-based lifestyle intervention (with or without trained volunteers with type 2 diabetes) reduced the risk of progression to type 2 diabetes in populations with a high-risk glycemic category. Design, Setting, and Participants: The Norfolk Diabetes Prevention Study was a parallel, 3-arm, group-based, randomized clinical trial conducted with up to 46 months of follow-up from August 2011 to January 2019 at 135 primary care practices and 8 intervention sites in the East of England. We identified 141 973 people at increased risk of type 2 diabetes, screened 12 778 (9.0%), and randomized those with a high-risk glycemic category, which was either an elevated fasting plasma glucose level alone (≥110 and <126 mg/dL [to convert to millimoles per liter, multiply by 0.0555]) or an elevated glycated hemoglobin level (≥6.0% to <6.5%; nondiabetic hyperglycemia) with an elevated fasting plasma glucose level (≥100 to <110 mg/dL). Interventions: A control arm receiving usual care (CON), a theory-based lifestyle intervention arm of 6 core and up to 15 maintenance sessions (INT), or the same intervention with support from diabetes prevention mentors, trained volunteers with type 2 diabetes (INT-DPM). Main Outcomes and Measures: Type 2 diabetes incidence between arms. Results: In this study, 1028 participants were randomized (INT, 424 [41.2%] [166 women (39.2%)]; INT-DPM, 426 [41.4%] [147 women (34.5%)]; CON, 178 [17.3%] [70 women (%39.3)]) between January 1, 2011, and February 24, 2017. The mean (SD) age was 65.3 (10.0) years, mean (SD) body mass index 31.2 (5) (calculated as weight in kilograms divided by height in meters squared), and mean (SD) follow-up 24.7 (13.4) months. A total of 156 participants progressed to type 2 diabetes, which comprised 39 of 171 receiving CON (22.8%), 55 of 403 receiving INT (13.7%), and 62 of 414 receiving INT-DPM (15.0%). There was no significant difference between the intervention arms in the primary outcome (odds ratio [OR], 1.14; 95% CI, 0.77-1.7; P = .51), but each intervention arm had significantly lower odds of type 2 diabetes (INT: OR, 0.54; 95% CI, 0.34-0.85; P = .01; INT-DPM: OR, 0.61; 95% CI, 0.39-0.96; P = .033; combined: OR, 0.57; 95% CI, 0.38-0.87; P = .01). The effect size was similar in all glycemic, age, and social deprivation groups, and intervention costs per participant were low at $153 (£122). Conclusions and Relevance: The Norfolk Diabetes Prevention lifestyle intervention reduced the risk of type 2 diabetes in current high-risk glycemic categories. Enhancing the intervention with DPM did not further reduce diabetes risk. These translatable results are relevant for current diabetes prevention efforts. Trial Registration: ISRCTN Registry Identifier: ISRCTN34805606.

'We're all in the same boat': A qualitative study on how groups work in a diabetes prevention and management programme.

OBJECTIVES: Although many health interventions are delivered in groups, it is unclear how group context can be best used to promote health-related behaviour change and what change processes are most helpful to participants. This study explored participants' experiences of attending type 2 diabetes prevention and management programme, and their perceptions of how group participation influenced changes in diet and physical activity. DESIGN: Qualitative. METHODS: Semi-structured telephone interviews were conducted with 20 participants (twelve men) from nine groups in the Norfolk Diabetes Prevention Study. Interviews were audio-recorded, transcribed verbatim, and analysed using thematic analysis in NVivo. RESULTS: Participants benefited from individual change processes, including information provision, structuring and prioritizing health goals, action planning, self-monitoring, and receiving feedback. They also benefited from group processes, including having a common purpose, sharing experiences, making social comparisons, monitoring and accountability, and providing and receiving social support in the groups. Participants' engagement with, and benefits from, the groups were enhanced when there was a supportive group context (i.e., group cohesion, homogeneous group composition, and a positive group atmosphere). Optimal facilitation to develop an appropriate group context and initiate effective change processes necessitated good facilitator interpersonal and professional skills, credibility and empathy, and effective group facilitation methods. Participants reported developing a sense of responsibility and making behaviour changes that resulted in improvements in health outcomes and weight loss. CONCLUSIONS: This study highlights the role of individual and group processes in facilitating health-promoting behaviour change, and the importance of group context and optimal facilitation in promoting engagement with the programme. Statement of contribution What is already known on this subject? Many health interventions, including programmes to help prevent or manage diabetes and facilitate weight loss, are delivered in groups. Such group-based behaviour-change interventions are often effective in facilitating psychological and behaviour change. There is considerable research and theory on individual change processes and techniques, but less is known about which change processes and techniques facilitate behaviour change in group settings. What does this study add? This study contributes to our understanding of how participating in group-based health programmes may enhance or impede individual behaviour change. It identified individual (intrapersonal) and group (interpersonal, facilitated through group interaction) change processes that were valued by group participants. The findings also show how these change processes may be affected by the group context. A diagram summarizes the identified themes helping to understand interactions between these key processes occurring in groups. The study offers an insight into participants' views on, and experiences of, attending a group-based diabetes prevention and management programme. Thus, it helps better understand how the intervention might have helped them (or not) and what processes may have influenced intervention outcomes. Key practical recommendations for designing and delivering group-based behaviour-change interventions are presented, which may be used to improve future group-based health interventions.

Recruitment, retention, and training of people with type 2 diabetes as diabetes prevention mentors (DPM) to support a healthcare professional-delivered diabetes prevention program: the Norfolk Diabetes Prevention Study (NDPS).

Objective: Intensive lifestyle interventions reduce the risk of type 2 diabetes in populations at highest risk, but staffing levels are usually unable to meet the challenge of delivering effective prevention strategies to a very large at-risk population. Training volunteers with existing type 2 diabetes to support healthcare professionals deliver lifestyle interventions is an attractive option. Methods: We identified 141 973 people at highest risk of diabetes in the East of England, screened 12 778, and randomized 1764 into a suite of type 2 diabetes prevention and screen detected type 2 diabetes management trials. A key element of the program tested the value of volunteers with type 2 diabetes, trained to act as diabetes prevention mentors (DPM) when added to an intervention arm delivered by healthcare professionals trained to support participant lifestyle change. Results: We invited 9951 people with type 2 diabetes to become DPM and 427 responded (4.3%). Of these, 356 (83.3%) were interviewed by phone, and of these 131 (36.8%) were interviewed in person. We then appointed 104 of these 131 interviewed applicants (79%) to the role (mean age 62 years, 55% (n=57) male). All DPMs volunteered for a total of 2895 months, and made 6879 telephone calls to 461 randomized participants. Seventy-six (73%) DPMs volunteered for at least 6 months and 66 (73%) for at least 1 year. Discussion: Individuals with type 2 diabetes can be recruited, trained and retained as DPM in large numbers to support a group-based diabetes prevention program delivered by healthcare professionals. This volunteer model is low cost, and accesses the large type 2 diabetes population that shares a lifestyle experience with the target population. This is an attractive model for supporting diabetes prevention efforts.