Diabetes Prevention Trial Research Articles

Preventing diabetes in primary care: a feasibility cluster randomized trial.

To determine the feasibility of implementing a large-scale primary care-based diabetes prevention trial. A feasibility cluster randomized controlled trial was conducted in British Columbia, Canada, amongst adults with prediabetes using the Facilitated Lifestyle Intervention Prescription (FLIP) vs. usual care. FLIP included lifestyle advice, a pedometer, and telephone support from a lifestyle facilitator for 6months. Indicators of feasibility included recruitment rates of family practices, participants and facilitators, as well as feasibility and retention rates in the FLIP program and study protocols. Six family practices participated; 59 patients were enrolled between October 2012 and March 2013. The trial protocol was acceptable to practices and participants and had a 95% participant retention rate over the 6 months (56/59). Adherence to the intervention was high (97%), with 34 of 35 patients continuing to receive telephone calls from the facilitator for 6 months. The mean cost of the intervention was C$144 per person. Compared with control, intervention participants significantly reduced weight by 3.2 kg (95% CI, 1.7 to 4.6); body mass index by 1.2 (95% CI, 0.7 to 1.7) and waist circumference by 3 cm (95% CI, 0.3 to 5.7). It is feasible to implement FLIP and to conduct a trial to assess effectiveness. A larger trial with longer follow up to assess progression to diabetes is warranted.

Rationale and design of the Vitamin D and Type 2 Diabetes (D2d) study: a diabetes prevention trial.

OBJECTIVEObservational studies suggest that vitamin D may lower the risk of type 2 diabetes. However, data from long-term trials are lacking. The Vitamin D and Type 2 Diabetes (D2d) study is a randomized clinical trial designed to examine whether a causal relationship exists between vitamin D supplementation and the development of diabetes in people at high risk for type 2 diabetes.RESEARCH DESIGN AND METHODSD2d was designed with support from a U34 planning grant from the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK). The final protocol was approved by the D2d Research Group, the data and safety monitoring board, and NIDDK. Key eligibility criteria are age ≥30 years, BMI of 24 (22.5 for Asian Americans) to 42 kg/m2, increased risk for diabetes (defined as meeting two of three glycemic criteria for prediabetes established by the American Diabetes Association [fasting glucose 100–125 mg/dL (5.5–6.9 mmol/L), 2-h postload glucose after 75-g glucose load 140–199 mg/dL (7.7–11.0 mmol/L), hemoglobin A1c 5.7–6.4% (39–46 mmol/mol)]), and no hyperparathyroidism, nephrolithiasis, or hypercalcemia. D2d participants are randomized to once-daily vitamin D3 (cholecalciferol 4,000 IU) or placebo and followed for an average of 3 years. The primary end point is time to incident diabetes as assessed by laboratory criteria during the study or by adjudication if diagnosed outside of D2d. Recruitment was initiated at the end of 2013.CONCLUSIONSD2d will test whether vitamin D supplementation is safe and effective at lowering the risk of progression to diabetes in people at high risk for type 2 diabetes.

Hypertriglyceridaemic waist phenotype as a simple predictive marker of incident diabetes in Asian-Indian men with prediabetes.

To determine prospectively the association of baseline hypertriglyceridaemic waist phenotype with incident diabetes in Asian-Indian men with impaired glucose tolerance. In a randomized 2-year diabetes prevention trial in 517 men with impaired glucose tolerance, 123 (23.8%) developed diabetes. Baseline anthropometric, metabolic and clinical variables were estimated. Associations of hypertriglyceridaemic waist phenotype (waist circumference ≥90cm and a serum triglyceride level of ≥ 1.7 mmol/l) with insulin resistance and incident diabetes were assessed using multiple linear regression and Cox's proportional hazard models, respectively. Men with an isolated enlarged waistline and hypertriglyceridaemic waist phenotype had significantly higher BMI and percentage of total body fat compared with the group with normal waistline and triglyceride levels and the group with isolated hypertriglyceridaemia. The men with hypertriglyceridaemic waist phenotype had higher insulin resistance (mean ± sd homeostasis model assessment of insulin resistance value: 3.6 ± 1.5) compared with those in the isolated enlarged waistline, the isolated hypertriglyceridaemia or the normal waistline and triglyceride level groups (3.1 ± 1.4, 2.7 ± 1.0 and 2.5 ± 1.1, respectively, all P <0.05 compared with hypertriglyceridaemic waist phenotype). Multiple linear regression analyses showed that hypertriglyceridaemic waist phenotype was significantly associated with insulin resistance after adjusting for age, BMI, family history, percentage of total body fat, smoking, alcohol intake, 2-h plasma glucose and HDL cholesterol level. Hypertriglyceridaemic waist phenotype was independently associated with incident diabetes after adjusting for the above confounders and gamma-glutamyl transferase (hazard ratio 1.49, 95% CI 1.01-2.21; P =0.047). The association of hypertriglyceridaemic waist phenotype with incident diabetes was abolished when insulin resistance was introduced into the model (hazard ratio 1.39, 95% CI 0.092-2.10; P=0.12). Hypertriglyceridaemic waist phenotype is a simple clinical proxy measurement for insulin resistance and is strongly associated with incident diabetes in Asian-Indian men with impaired glucose tolerance.

Long-term changes in dietary and food intake behaviour in the Diabetes Prevention Program Outcomes Study.

To compare change in dietary intake, with an emphasis on food groups and food intake behaviour, over time across treatment arms in a diabetes prevention trial and to assess the differences in dietary intake among demographic groups within treatment arms. Data are from the Diabetes Prevention Program and Diabetes Prevention Program Outcomes Study. Participants were randomized to a lifestyle intervention (n = 1079), metformin (n = 1073) or placebo (n = 1082) for an average of 3years, after which the initial results regarding the benefits of the lifestyle intervention were released and all participants were offered a modified lifestyle intervention. Dietary intake was assessed using a food frequency questionnaire at baseline and at 1, 5, 6 and 9years after randomization. Compared with the metformin and placebo arms, participants in the lifestyle arm maintained a lower total fat and saturated fat and a higher fibre intake up to 9years after randomization and lower intakes of red meat and sweets were maintained for up to 5years. Younger participants had higher intakes of poultry and lower intakes of fruits compared with their older counterparts, particularly in the lifestyle arm. Black participants tended to have lower dairy and higher poultry intakes compared with white and Hispanic participants. In the lifestyle arm, men tended to have higher grain, fruit and fish intakes than women. Changes in nutrient intake among participants in the lifestyle intervention were maintained for up to 9years. Younger participants reported more unhealthy diets over time and thus may benefit from additional support to achieve and maintain dietary goals.

Design and methods of “diaBEAT-it!”: A hybrid preference/randomized control trial design using the RE-AIM framework

BackgroundDiabetes prevention is a public health priority that is dependent upon the reach, effectiveness, and cost of intervention strategies. However, understanding each of these outcomes within the context of randomized controlled trials is problematic. PurposeTo describe the methods and design of a hybrid preference/randomized control trial using the RE-AIM framework. MethodsThe trial, which was developed using the RE-AIM framework, will contrast the effects of 3 interventions: (1) a standard care, small group, diabetes prevention education class (SG), (2) the small group intervention plus 12months of interactive voice response telephone follow-up (SG–IVR), and (3) a DVD version of the small group intervention with the same IVR follow-up (DVD–IVR). Each intervention includes personal action planning with a focus on key elements of the lifestyle intervention from the Diabetes Prevention Program (DPP). Adult patients at risk for diabetes will be randomly assigned to either choice or RCT. Those assigned to choice (n=240) will have the opportunity to choose between SG–IVR and DVD–IVR. Those assigned to RCT group (n=360) will be randomly assigned to SG, SG–IVR, or DVD–IRV. Assessment of primary (weight loss, reach, & cost) and secondary (physical activity, & dietary intake) outcomes will occur at baseline, 6, 12, and 18months. ConclusionThis will be the first diabetes prevention trial that will allow the research team to determine the relationships between reach, effectiveness, and cost of different interventions.

SLIMMER: a randomised controlled trial of diabetes prevention in Dutch primary health care: design and methods for process, effect, and economic evaluation

BackgroundImplementation of interventions in real-life settings requires a comprehensive evaluation approach. The aim of this article is to describe the evaluation design of the SLIMMER diabetes prevention intervention in a Dutch real-life setting.Methods/DesignThe SLIMMER study is a randomised, controlled intervention study including subjects aged 40 through 70 years with impaired fasting glucose or high risk of diabetes. The 10-month SLIMMER intervention involves a dietary and physical activity intervention, including case management and a maintenance programme. The control group receives usual health care and written information about a healthy lifestyle. A logic model of change is composed to link intervention activities with intervention outcomes in a logical order. Primary outcome is fasting insulin. Measurements are performed at baseline and after 12 and 18 months and cover quality of life, cardio-metabolic risk factors (e.g. glucose tolerance, serum lipids, body fatness, and blood pressure), eating and physical activity behaviour, and behavioural determinants. A process evaluation gives insight in how the intervention was delivered and received by participants and health care professionals. The economic evaluation consists of a cost-effectiveness analysis and a cost-utility analysis. Costs are assessed from both a societal and health care perspective.DiscussionThis study is expected to provide insight in the effectiveness, including its cost-effectiveness, and delivery of the SLIMMER diabetes prevention intervention conducted in Dutch primary health care. Results of this study provide valuable information for primary health care professionals, researchers, and policy makers.Trial registrationThe SLIMMER study is registered with ClinicalTrials.gov (NCT02094911) since March 19, 2014.

Cardiovascular risk stratification and management in pre-diabetes.

Prediabetes, covering individuals with impaired fasting glycemia, impaired glucose tolerance, or high-risk HbA1c levels, is associated with a ∼20 % increased risk of developing cardiovascular disease (CVD) compared with normoglycemic individuals. It is well-known that lifestyle or pharmacologic interventions can prevent diabetes in prediabetic people; however, the evidence is less clear regarding prevention of CVD. Most diabetes prevention trials have failed to show beneficial effects on CVD morbidity and mortality despite significant improvements of CVD risk factors in individuals with prediabetes. Another challenge is how to estimate CVD risk in prediabetic people. In general, prediction models for CVD do not take glucose levels or prediabetes status into account, thereby underestimating CVD risk in these high-risk individuals. More evidence within risk stratification and management of CVD risk in prediabetes is needed in order to recommend useful and effective strategies for early prevention of CVD.

Design and Analysis of Diabetes Prevention Trials for Glucose-Lowering Drugs

For diseases assessed by disease symptoms it is difficult to distinguish whether interventions slow, stabilize, or reverse the disease, or only reduce symptoms. For example, when testing glucose-lowering drugs for delaying or preventing type 2 diabetes, reduced rates of diabetes diagnoses based on glycemic values do not directly answer this question, because glucose lowering reduces this surrogate without necessarily benefiting prediabetic individuals. A washout could evaluate whether effects persist after eliminating any direct glucose lowering. Several trials analyzed cumulative diabetes diagnoses, from a treatment period including a washout in not-yet-diagnosed subjects. This approach is severely biased, as demonstrated by simulations, because different misclassification errors occur unequally on drug and placebo as a result of the glucose-lowering effect during active treatment and the variability of glycemic values. An alternative is to analyze continuous end-of-washout values for all patients. This requires an imputation of glycemic values after diabetes diagnosis, which can no longer be observed without distortion by physician intervention. Valid imputation is possible, because the known diagnostic criteria lead to a missing at random situation. Trials with a washout in all subjects or delayed start designs are more efficient than current trial designs, and also minimize reliance on data imputation.

The Multigroup Ethnic Identity Measure—Revised: Measurement invariance across racial and ethnic groups.

The Multigroup Ethnic Identity Measure-Revised (MEIM-R), a brief instrument assessing affiliation with one's ethnic group, is a promising advance in the ethnic identity literature. However, equivalency of its measurement properties across specific racial and ethnic groups should be confirmed before using it in diverse samples. We examined (a) the psychometric properties of the MEIM-R, including factor structure, measurement invariance, and internal consistency reliability, and (b) levels of and differences in ethnic identity across multiple racial and ethnic groups and subgroups. Asian (n = 630), Black/African American (n = 58), Hispanic (n = 240), multiethnic (n = 160), and White (n = 375) women completed the MEIM-R as part of the "Gestational diabetes' Effect on Moms" diabetes prevention trial in the Kaiser Permanente Northern California health care setting (N = 1,463; M age = 32.5 years, SD = 4.9). Multiple-groups confirmatory factor analyses provided provisional evidence of measurement invariance, i.e., an equal, correlated 2-factor structure, equal factor loadings, and equal item intercepts across racial and ethnic groups. Latent factor means for the 2 MEIM-R subscales, exploration and commitment, differed across groups; effect sizes ranging from small to large generally supported the notion of ethnic identity as more salient among people of color. Pending replication, good psychometric properties in this large and diverse sample of women support the future use of the MEIM-R. Preliminary evidence of measurement invariance suggests that the MEIM-R could be used to measure and compare ethnic identity across multiple racial and ethnic groups.

Large-Scale Prospective T Cell Function Assays in Shipped, Unfrozen Blood Samples: Experiences from the Multicenter TRIGR Trial

Broad consensus assigns T lymphocytes fundamental roles in inflammatory, infectious, and autoimmune diseases. However, clinical investigations have lacked fully characterized and validated procedures, equivalent to those of widely practiced biochemical tests with established clinical roles, for measuring core T cell functions. The Trial to Reduce Insulin-dependent diabetes mellitus in the Genetically at Risk (TRIGR) type 1 diabetes prevention trial used consecutive measurements of T cell proliferative responses in prospectively collected fresh heparinized blood samples shipped by courier within North America. In this article, we report on the quality control implications of this simple and pragmatic shipping practice and the interpretation of positive- and negative-control analytes in our assay. We used polyclonal and postvaccination responses in 4,919 samples to analyze the development of T cell immunocompetence. We have found that the vast majority of the samples were viable up to 3 days from the blood draw, yet meaningful responses were found in a proportion of those with longer travel times. Furthermore, the shipping time of uncooled samples significantly decreased both the viabilities of the samples and the unstimulated cell counts in the viable samples. Also, subject age was significantly associated with the number of unstimulated cells and T cell proliferation to positive activators. Finally, we observed a pattern of statistically significant increases in T cell responses to tetanus toxin around the timing of infant vaccinations. This assay platform and shipping protocol satisfy the criteria for robust and reproducible long-term measurements of human T cell function, comparable to those of established blood biochemical tests. We present a stable technology for prospective disease-relevant T cell analysis in immunological diseases, vaccination medicine, and measurement of herd immunity.

Recruitment and retention of participants for an international type 1 diabetes prevention trial: a coordinators' perspective.

The Trial to Reduce Insulin Dependent Diabetes Mellitus in the Genetically at Risk (TRIGR) is the first multicenter international type 1 diabetes (T1D) prevention trial to be undertaken. A unique feature of TRIGR has been recruitment of eligible pregnant women and enrollment of newborns for long-term follow-up assessments. Our purpose is to summarize the recruitment and retention strategies used to conduct TRIGR from the perspective of the study coordinators. TRIGR was designed to test whether weaning to formula containing hydrolyzed versus intact cow's milk protein would be efficacious in decreasing risk for development of T1D-associated autoantibodies and T1D among infants identified to be at increased risk for T1D based on their human leukocyte antigen (HLA) profile and family history. Multiple strategies tailored to local issues were required to enroll and follow the target number of infants. This study was conducted in the United States, Canada, Australia, and 12 countries in Europe. Of the 5606 mothers registered worldwide, 5000 of their infants were randomized. Of these, 2159 were HLA eligible and enrolled in the 8-month intervention and 10-year follow-up phases of this study. The TRIGR study met the accrual goal after 4.7 years of recruitment, 2.7 years longer than projected initially. Challenges included difficulty in finding fathers with T1D, a higher than expected rate of premature delivery among T1D mothers, and implementation of new privacy regulations mid-trial. The majority of participants were recruited from primary care antenatal clinics located near the study centers and from a general hospital or pediatric center that was affiliated with a TRIGR Study center. Internet and magazine advertisements were found to be useful for recruitment of families. Alternative follow-up strategies are offered to families who wish to reduce or discontinue participation. Our experience is limited to a single international multicenter trial. TRIGR coordinators played key roles in the recruitment and intervention periods and continue to be instrumental in retaining families and children during the 10-year follow-up period for each child.

Long-Term Effects of Diabetes Prevention: Evaluation of the M.O.B.I.L.I.S. Program for Obese Persons

In response to the growing burden of obesity, public primary prevention programs against obesity have been widely recommended. Several studies estimated the cost effects of diabetes prevention trials for different countries and found that diabetes prevention can be costeffective. Nevertheless, it is still controversial if prevention conducted in more real-world settings and among people with increased risk but not yet exhibiting Increased Glucose Tolerance can really be a cost-effective strategy to cope with the obesity epidemic. We examine this question in a simulation model based on the results of the M.O.B.I.L.I.S program, a German lifestyle intervention to reduce obesity, which is directed on the high-risk group of people who are already obese. The contribution of this paper is the use of 4-year follow-up data on the intervention group and a comparison with a control group formed by SOEP respondents as inputs in a Markov model of the long-term benefits of this intervention due to prevention of type-2 diabetes.

The Association of Genetic Markers for Type 2 Diabetes with Prediabetic Status - Cross-Sectional Data of a Diabetes Prevention Trial

ObjectiveTo investigate the association of risk alleles for type 2 diabetes with prediabetes accounting for age, anthropometry, inflammatory markers and lifestyle habits.DesignCross-sectional study of 129 men and 157 women of medium-sized companies in northern Germany in the Delay of Impaired Glucose Tolerance by a Healthy Lifestyle Trial (DELIGHT).MethodsBesides established risk factors, 41 single nucleotide polymorphisms (SNPs) that have previously been found to be associated with type 2 diabetes were analyzed. As a nonparametric test a random forest approach was used that allows processing of a large number of predictors. Variables with the highest impact were entered into a multivariate logistic regression model to estimate their association with prediabetes.ResultsIndividuals with prediabetes were characterized by a slightly, but significantly higher number of type 2 diabetes risk alleles (42.5±4.1 vs. 41.3±4.1, p = 0.013). After adjustment for age and waist circumference 6 SNPs with the highest impact in the random forest analysis were associated with risk for prediabetes in a logistic regression model. At least 5 of these SNPs were positively related to prediabetic status (odds ratio for prediabetes 1.57 per allele (Cl 1.21–2.10, p = 0.001)).ConclusionsThis explorative analysis of data of DELIGHT demonstrates that at least 6 out of 41 genetic variants characteristic of individuals with type 2 diabetes may also be associated with prediabetes. Accumulation of these risk alleles may markedly increase the risk for prediabetes. However, prospective studies are required to corroborate these findings and to demonstrate the predictive value of these genetic variants for the risk to develop prediabetes.

The use of intermediate endpoints in the design of type 1 diabetes prevention trials.

This paper presents a rationale for the selection of intermediate endpoints to be used in the design of type 1 diabetes prevention clinical trials. Relatives of individuals diagnosed with type 1 diabetes were enrolled on the TrialNet Natural History Study and screened for diabetes-related autoantibodies. Those with two or more such autoantibodies were analysed with respect to increased HbA1c, decreased C-peptide following an OGTT, or abnormal OGTT values as intermediate markers of disease progression. Over 2 years, a 10% increase in HbA1c, and a 20% or 30% decrease in C-peptide from baseline, or progression to abnormal OGTT, occurred with a frequency between 20% and 41%. The 3- to 5-year risk of type 1 diabetes following each intermediate endpoint was high, namely 47% to 84%. The lower the incidence of the endpoint being reached, the higher the risk of diabetes. A diabetes prevention trial using these intermediate endpoints would require a 30% to 50% smaller sample size than one using type 1 diabetes as the endpoint. The use of an intermediate endpoint in diabetes prevention is based on the generally held view of disease progression from initial occurrence of autoantibodies through successive immunological and metabolic changes to manifest type 1 diabetes. Thus, these markers are suitable for randomised phase 2 trials, which can more rapidly screen promising new therapies, allowing them to be subsequently confirmed in definitive phase 3 trials.

In antibody-positive first-degree relatives of patients with type 1 diabetes, HLA-A*24 and HLA-B*18, but not HLA-B*39, are predictors of impending diabetes with distinct HLA-DQ interactions.

Secondary type 1 diabetes prevention trials require selection of participants with impending diabetes. HLA-A and -B alleles have been reported to promote disease progression. We investigated whether typing for HLA-B*18 and -B*39 may complement screening for HLA-DQ8, -DQ2 and -A*24 and autoantibodies (Abs) against islet antigen-2 (IA-2) and zinc transporter 8 (ZnT8) for predicting rapid progression to hyperglycaemia. A registry-based group of 288 persistently autoantibody-positive (Ab(+)) offspring/siblings (aged 0-39 years) of known patients (Ab(+) against insulin, GAD, IA-2 and/or ZnT8) were typed for HLA-DQ, -A and -B and monitored from the first Ab(+) sample for development of diabetes within 5 years. Unlike HLA-B*39, HLA-B*18 was associated with accelerated disease progression, but only in HLA-DQ2 carriers (p < 0.006). In contrast, HLA-A*24 promoted progression preferentially in the presence of HLA-DQ8 (p < 0.002). In HLA-DQ2- and/or HLA-DQ8-positive relatives (n = 246), HLA-B*18 predicted impending diabetes (p = 0.015) in addition to HLA-A*24, HLA-DQ2/DQ8 and positivity for IA-2A or ZnT8A (p ≤ 0.004). HLA-B*18 interacted significantly with HLA-DQ2/DQ8 and HLA-A*24 in the presence of IA-2 and/or ZnT8 autoantibodies (p ≤ 0.009). Additional testing for HLA-B*18 and -A*24 significantly improved screening sensitivity for rapid progressors, from 38% to 53%, among relatives at high Ab-inferred risk carrying at least one genetic risk factor. Screening for HLA-B*18 increased sensitivity for progressors, from 17% to 28%, among individuals carrying ≥ 3 risk markers conferring >85% 5 year risk. These results reinforce the importance of HLA class I alleles in disease progression and quantify their added value for preparing prevention trials.

Lifestyle change in Kerala, India: needs assessment and planning for a community-based diabetes prevention trial

Lifestyle change in Kerala, India: needs assessment and planning for a community-based diabetes prevention trial

Lifestyle change in Kerala, India: needs assessment and planning for a community-based diabetes prevention trial

BackgroundType 2 Diabetes Mellitus (T2DM) has become a major public health challenge in India. Factors relevant to the development and implementation of diabetes prevention programmes in resource-constrained countries, such as India, have been under-studied. The purpose of this study is to describe the findings from research aimed at informing the development and evaluation of a Diabetes Prevention Programme in Kerala, India (K-DPP).MethodsData were collected from three main sources: (1) a systematic review of key research literature; (2) a review of relevant policy documents; and (3) focus groups conducted among individuals with a high risk of progressing to diabetes. The key findings were then triangulated and synthesised.ResultsPrevalence of risk factors for diabetes is very high and increasing in Kerala. This situation is largely attributable to rapid changes in the lifestyle of people living in this state of India. The findings from the systematic review and focus groups identified many environmental and personal determinants of these unhealthy lifestyle changes, including: less than ideal accessibility to and availability of health services; cultural values and norms; optimistic bias and other misconceptions related to risk; and low expectations regarding one’s ability to make lifestyle changes in order to influence health and disease outcomes. On the other hand, there are existing intervention trials conducted in India which suggests that risk reduction is possible. These programmes utilize multi-level strategies including mass media, as well as strategies to enhance community and individual empowerment. India’s national programme for the prevention and control of major non-communicable diseases (NCD) also provide a supportive environment for further community-based efforts to prevent diabetes.ConclusionThese findings provide strong support for undertaking more research into the conduct of community-based diabetes prevention in the rural areas of Kerala. We aim to develop, implement and evaluate a group-based peer support programme that will address cultural and family determinants of lifestyle risks, including family decision-making regarding adoption of healthy dietary and physical activity patterns. Furthermore, we believe that this approach will be feasible, acceptable and effective in these communities; with the potential for scale-up in other parts of India.

Long-Term Effects of Diabetes Prevention: Evaluation of the M.O.B.I.L.I.S. Program for Obese Persons

In response to the growing burden of obesity, public primary prevention programs against obesity have been widely recommended. Several studies estimated the cost effects of diabetes prevention trials for different countries and found that diabetes prevention can be costeffective. Nevertheless, it is still controversial if prevention conducted in more real-world settings and among people with increased risk but not yet exhibiting Increased Glucose Tolerance can really be a cost-effective strategy to cope with the obesity epidemic. We examine this question in a simulation model based on the results of the M.O.B.I.L.I.S program, a German lifestyle intervention to reduce obesity, which is directed on the high-risk group of people who are already obese. The contribution of this paper is the use of 4-year follow-up data on the intervention group and a comparison with a control group formed by SOEP respondents as inputs in a Markov model of the long-term benefits of this intervention due to prevention of type-2 diabetes.

Fruit and vegetable intake and the association with glucose parameters: a cross-sectional analysis of the Let’s Prevent Diabetes Study

Dietary recommendations for the prevention of type 2 diabetes mellitus include the message to consume 400 g fruit and vegetables per day. Measurement of habitual diet is inherently difficult, yet errors due to self-report can be eliminated by the use of nutritional biomarkers. The aim of this study was to determine plasma vitamin C concentrations as a biomarker for fruit and vegetable intake in individuals identified at high risk of diabetes. Fruit and vegetables may confer benefit via their antioxidant capacity, thus we also measured urinary F₂-isoprostanes as a marker for oxidative stress. Participants recruited from a high-risk population as part of a diabetes prevention trial provided fasting blood samples and a spot urine sample for the quantification of plasma vitamin C and F₂-isoprostanes, respectively. We compared glycaemic parameters by the increments of the standard deviation of plasma vitamin C using multiple regression models. Mean plasma vitamin C of participants was 39.3 μmol/l (s.d. 21.8). In the unadjusted model, 1 s.d. plasma vitamin C was significantly and inversely associated with HbA1c, fasting and 2 h blood glucose (P ≤ 0.0001). Relationships remained significant after adjustment for demographic variables and confounding factors. No significant association was observed between plasma vitamin C and urinary F₂-isoprostanes. The data adds to the evidence that small lifestyle changes may influence glucose regulation. The role that fruit and vegetables independently have should be investigated further.

Implementation of the automated Leicester Practice Risk Score in two diabetes prevention trials provides a high yield of people with abnormal glucose tolerance

The Leicester Practice Risk Score (LPRS) is a tool for identifying those at high risk of either impaired glucose regulation (IGR), defined as impaired glucose tolerance and/or impaired fasting glucose, or type 2 diabetes from routine primary care data. The aim of this study was to determine the yield from the LPRS when applied in two diabetes prevention trials. Let's Prevent Diabetes (LPD) and Walking Away from Diabetes (WAD) studies used the LPRS to identify people at risk of IGR or type 2 diabetes from 54 general practices. The top 10% at risk within each practice were invited for screening using a 75 g OGTT. The response rate to the invitation and the prevalence of IGR and/or type 2 diabetes in each study were calculated. Of those invited 19.2% (n = 3,449) in LPD and 22.1% (n = 833) in WAD attended. Of those screened for LPD 25.5% (95% CI 24.1, 27.0) had IGR and 4.5% (95% CI 3.8, 5.2) had type 2 diabetes, giving a prevalence of any abnormal glucose tolerance of 30.1% (95% CI 28.5, 31.6). Comparable rates were seen for the WAD study: IGR 26.5% (95% CI 23.5, 29.5), type 2 diabetes 3.0% (95% CI 1.8, 4.2) and IGR/type 2 diabetes 29.5% (95% CI 26.4, 32.6). Using the LPRS identifies a high yield of people with abnormal glucose tolerance, significantly higher than those seen in a population screening programme in the same locality. The LPRS is an inexpensive and simple way of targeting screening programmes at those with the highest risk.