The Diabetes Prevention Program: baseline characteristics of the randomized cohort. The Diabetes Prevention Program Research Group

Evidence of a bi-directional relationship between heart failure and diabetes: a strategy for the detection of glucose abnormalities and diabetes prevention in patients with heart failure

Prevalence of heart failure (HF) and diabetes are markedly increasing globally. In a population of HF patients, approximately 40% have diabetes which is associated with a more severe HF, poorer cardiovascular outcomes and higher hospitalization rates for HF than HF patients without diabetes. Similar trends were shown in HF patients with prediabetes. In addition, the association between HF and renal function decline was demonstrated in patients with or without diabetes. However, the exact prevalence of dysglycemia in HF patients requires further investigation aiming to clarify the most accurate test to detect dysglycemia in this population. The relationship between HF and diabetes is complex and probably bidirectional. In one way, patients with diabetes have a more than two-fold risk of developing incident HF with reduced or preserved ejection fraction than those without diabetes. In the other way, patients with HF, when compared with those without HF, show an increased risk for the onset of diabetes due to several mechanisms including insulin resistance (IR), which makes HF emerging as a precursor for diabetes development. This article provides epidemiological evidence of undetected dysglycemia (prediabetes or diabetes) in HF patients and reviews the pathophysiological mechanisms which favor the development of IR and the risks associated with these disorders in HF patients. This review also offers a discussion of various strategies for the prevention of diabetes in HF patients, based first on fasting plasma glucose and HbA1c measurement and if normal on an oral glucose tolerance test as diagnostic tools for prediabetes and unknown diabetes that should be performed more extensively in those patients. It discusses the implementation of diabetes prevention measures and well-structured management programs for HF patients who are generally overweight or obese, as well as current pharmacotherapeutic options for prediabetes, including sodium-glucose cotransporter 2 inhibitors which are among the pillars of HF treatment and which recently showed a benefit in the reduction of incident diabetes in HF patients. Thus, there is an urgent need of routine screening for dysglycemia in all HF patients, which should contribute to reduce the incidence of diabetes and to treat earlier diabetes when already present.

Longitudinal associations between microRNAs and weight in the diabetes prevention program

Objective

Circulating microRNAs show cross-sectional associations with overweight and obesity. Few studies provided data to differentiate between a snapshot perspective on these associations versus how microRNAs characterize prodromal risk from disease pathology and complications. This study assessed longitudinal relationships between circulating microRNAs and weight at multiple time-points in the Diabetes Prevention Program trial.

Research design and methods

A subset of participants (n=150) from the Diabetes Prevention Program were included. MicroRNAs were measured from banked plasma using a Fireplex Assay. We used generalized linear mixed models to evaluate relationships between microRNAs and changes in weight at baseline, year-1, and year-2. Logistic regression was used to evaluate whether microRNAs at baseline were associated with weight change after 2 years.

Results

In fully adjusted models that included relevant covariates, seven miRs (i.e., miR-126, miR-15a, miR-192, miR-23a, and miR-27a) were statistically associated with weight over 2 years. MiR-197 and miR-320a remained significant after adjustment for multiple comparisons. Baseline levels of let-7f, miR-17, and miR-320c were significantly associated with 3% weight loss after 2 years in fully adjusted models.

Discussion

This study provided evidence for longitudinal relationships between circulating microRNAs and weight. Because microRNAs characterize the combined effects of genetic determinants and responses to behavioral determinants, they may provide insights about the etiology of overweight and obesity in the context or risk for common, complex diseases. Additional studies are needed to validate the potential genes and biological pathways that might be targeted by these microRNA biomarkers and have mechanistic implications for weight loss and disease prevention.

How effective are church-based weight-loss interventions among Black adults? A systematic review

OBJECTIVE

Churches are frequently used to reach Black adults to effect weight loss. However, there has been no recent review, to our knowledge, inclusive of solely Black adults in church settings. We sought to comprehensively examine the methodological approaches and weight-loss outcomes of church-based weight-loss lifestyle interventions conducted among Black adults to provide insights on literature gaps and offer suggestions for future research.

METHODS

Google Scholar, PubMed, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) were searched for trials conducted in churches that reported weight outcomes at any time point. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guided manuscript development.

RESULTS

A total of 15 studies (N = 2285) from 2007 to 2023 met inclusion criteria, and 33% were high-quality randomized trials. The majority were pilot studies (60%) conducted in the Southern United States. Most reported significant postintervention weight loss. The follow-up time points varied from 2 to 12 months. Methodological approaches included the following: cultural adaptations (93%); theory-guided (93%); delivered by community health workers (80%); and delivered in person in a group format (100%). Only one study offered individual-level attention beyond texts/emails. Most participants were well-educated female individuals.

CONCLUSIONS

Weight-loss interventions among Black church settings effect statistically significant weight loss, albeit in a small way. Limitations include pilot studies and small samples. More rigorously designed studies are warranted.

Increased Genetic Risk for β-Cell Failure Is Associated With β-Cell Function Decline in People With Prediabetes

Partitioned polygenic scores (pPS) have been developed to capture pathophysiologic processes underlying type 2 diabetes (T2D). We investigated the association of T2D pPS with diabetes-related traits and T2D incidence in the Diabetes Prevention Program. We generated five T2D pPS (β-cell, proinsulin, liver/lipid, obesity, lipodystrophy) in 2,647 participants randomized to intensive lifestyle, metformin, or placebo arms. Associations were tested with general linear models and Cox regression with adjustment for age, sex, and principal components. Sensitivity analyses included adjustment for BMI. Higher β-cell pPS was associated with lower insulinogenic index and corrected insulin response at 1-year follow-up with adjustment for baseline measures (effect per pPS SD -0.04, P = 9.6 × 10-7, and -8.45 μU/mg, P = 5.6 × 10-6, respectively) and with increased diabetes incidence with adjustment for BMI at nominal significance (hazard ratio 1.10 per SD, P = 0.035). The liver/lipid pPS was associated with reduced 1-year baseline-adjusted triglyceride levels (effect per SD -4.37, P = 0.001). There was no significant interaction between T2D pPS and randomized groups. The remaining pPS were associated with baseline measures only. We conclude that despite interventions for diabetes prevention, participants with a high genetic burden of the β-cell cluster pPS had worsening in measures of β-cell function.

ARTICLE HIGHLIGHTS

The association of insulin responses and insulin sensitivity with cognition in adults with pre-diabetes: The Diabetes Prevention Program Outcomes Study

OBJECTIVE

Dysglycemia is a significant risk factor for cognitive impairment. However, which pathophysiologic determinant(s) of dysglycemia, impaired insulin sensitivity (ISens) or the islet β-cell's response (IResp), contribute to poorer cognitive function, independent of dysglycemia is not established. Among 1052 adults with pre-diabetes from the Diabetes Prevention Program Outcomes Study (DPPOS), we investigated the relationship between IResp, ISens and cognitive function.

RESEARCH DESIGN AND METHODS

IResp was estimated by the insulinogenic index (IGI; pmol/mmol) and ISens as 1/fasting insulin from repeated annual oral glucose tolerance tests. The mean IResp and mean ISens were calculated over approximately 12 years of follow-up. Verbal learning (Spanish-English Verbal Learning Test [SEVLT]) and executive function (Digital Symbol Substitution Test [DSST]) were assessed at the end of the follow-up period. Linear regression models were run for each cognitive outcome and were adjusted for dysglycemia and other factors.

RESULTS

Higher IResp was associated with poorer performance on the DSST (-0.69 points per 100 unit increase in IGI, 95 % CI: -1.37, -0.01). ISens was not associated with DSST, nor were IResp or ISens associated with performance on the SEVLT.

CONCLUSIONS

These results suggest that a greater β-cell response in people at high risk for type 2 diabetes is associated with poorer executive function, independent of dysglycemia and ISens.

Enhancing Lifestyles in the Metabolic syndrome (ELM) multisite behavioral efficacy trial. Design and baseline cohort

BACKGROUND

Prevalence of metabolic syndrome (MetS) increased from one-quarter to one-third of the U.S. adult population over 8 years and is spreading to young adults and Asian and Hispanic Americans. Diagnosed when >3 out of 5 cardiometabolic risk factors are present, there is widespread agreement that its fundamental roots are in a lifestyle characterized by poor dietary quality and physical inactivity. Past lifestyle trials for MetS produce benefits that have limited sustainability, suggesting the need for new treatment approaches.

METHODS

This is the design and baseline cohort of the Enhancing Lifestyles in the Metabolic Syndrome (ELM) multi-site trial. The trial tests the hypothesis that a habit-based lifestyle treatment offered over 6 months, followed by 18 monthly maintenance contacts, can produce 4 new diet, physical activity, and mindfulness habits and, if so, sustained MetS remission. The design is an individually randomized, partially clustered group treatment trial of 618 participants with the MetS recruited from 5 sites in the U.S. and randomized to a small group lifestyle treatment or an enhanced standard of care education comparator. The primary outcome is MetS remission at 24 months. Secondary outcomes compare arms at 6, 15, and 24 months on MetS components, lifestyle targets, weight, body mass index, hemoglobin A1c, LDL cholesterol, medications, quality of life, psychosocial factors, and cost-effectiveness.

RESULTS

The cohort of 618 participants was recruited by screening 14,817 over 2.5 years (screening to enrollment ratio 24:1). Recruitment exceeded the target of 600 despite 2 COVID-19 pauses. The mean age was 55.5 years, 24.3% were male, 25.5% were a racial minority, 9.7% identified as Hispanic, and 83.0% were classified as obese (body mass index >30). The most common MetS components were abdominal obesity (97.7%) and elevated blood pressure or antihypertensive medication (86.2%).

CONCLUSIONS

The geographic, sociodemographic, and clinical diversity of the cohort, combined with rigorous behavioral efficacy trial methods, will provide a conclusive answer to the question of whether this habit-based lifestyle program can produce sustained 24-month remission of the MetS and thereby help to curb a significant and growing public health problem.

Prevalence and predictors of female sexual dysfunction among sexually active women in the diabetes prevention program outcomes study

OBJECTIVE

To determine the burden and identify correlates of female sexual dysfunction (FSD) among women with prediabetes (PreD) and type 2 diabetes (T2D) enrolled in the Diabetes Prevention Program (DPP) Outcomes Study (DPPOS).

METHODS

The DPPOS visit included the Female Sexual Function Index (FSFI) to determine sexual function. Of 1464 participants, 1320 (90%) completed the (FSFI) and 426 were sexually active. A backward selection multivariable logistic regression model estimated the odds of FSD for sociodemographic, clinical, and diabetes-related covariates.

RESULTS

One hundred and eighty-five (43%) had a score of ≤26.55 and met the criteria for FSD. After adjustment for DPP treatment and age, urinary incontinence (UI) (odds ratio [OR] = 1.91, 95% confidence interval [CI] = 1.15-3.17) and hysterectomy (OR = 1.89, 95% CI = 1.01-3.53) were associated with increased odds of FSD. Increased body mass index was protective for FSD (OR = 0.93 per kg/m2, 95% CI = 0.89-0.96). Michigan Neuropathy Screening Instrument-based peripheral neuropathy (mean±SD scores 1.1±1.3 vs. 0.9±1.1, p < 0.0001) and Electrocardiogram (ECG)-based autonomic dysfunction measures (mean ± SD heart rate levels 64.3 ± 6.8 vs. 65.6 ± 10.2, p = 0.008) were associated with FSD. There were no differences in diabetes rates between women who did (66.5%) and did not (66%) have (p = 0.7).

CONCLUSIONS

FSD is prevalent in women with PreD and T2D. Our findings suggest that FSD is associated with neuropathic complications commonly observed in PreD and T2D.

Rosiglitazone improves insulin resistance but does not improve exercise capacity in individuals with impaired glucose tolerance: A randomized clinical study

Dysmetabolic states, such as type 2 diabetes (T2D), characterized by insulin resistance (IR), are associated with fatty liver, increased cardiovascular disease (CVD) risk, and decreased functional exercise capacity (FEC). Rosiglitazone (RO) improves exercise capacity and IR in T2D. However, the effects of RO on FEC and other markers of CVD risk in prediabetes are unknown. We hypothesized that insulin sensitization with RO would improve exercise capacity and markers of CVD risk in participants with impaired glucose tolerance (IGT). Exercise performance (peak oxygen consumption and oxygen uptake kinetics), IR (homeostasis model assessment of IR and quantitative insulin sensitivity check index), and surrogate cardiovascular endpoints (coronary artery calcium (CAC) volume and density and C-reactive protein (CRP)) were measured in participants with IGT after 12 and 18 months of RO or placebo (PL). RO did not significantly improve exercise capacity. Glycemic measures and IR were significantly lower in people on RO compared to PL at 18 months. CAC volume progression was not different between PL and RO groups. RO did not improve exercise capacity during an 18-month intervention despite improved IR and glycemia in people with IGT. Future studies should explore why effects on FEC with RO occur in T2D but not IGT. Understanding these questions may help in targeting therapeutic approaches in T2D and IGT.

Statistical Methods to Evaluate Surrogate Markers

BACKGROUND

There is tremendous interest in evaluating surrogate markers given their potential to decrease study time, costs, and patient burden.

OBJECTIVES

The purpose of this statistical workshop article is to describe and illustrate how to evaluate a surrogate marker of interest using the proportion of treatment effect (PTE) explained as a measure of the quality of the surrogate marker for: (1) a setting with a general fully observed primary outcome (eg, biopsy score); and (2) a setting with a time-to-event primary outcome which may be censored due to study termination or early drop out (eg, time to diabetes).

METHODS

The methods are motivated by 2 randomized trials, one among children with nonalcoholic fatty liver disease where the primary outcome was a change in biopsy score (general outcome) and another study among adults at high risk for Type 2 diabetes where the primary outcome was time to diabetes (time-to-event outcome). The methods are illustrated using the Rsurrogate package with a detailed R code provided.

RESULTS

In the biopsy score outcome setting, the estimated PTE of the examined surrogate marker was 0.182 (95% confidence interval [CI]: 0.121, 0.240), that is, the surrogate explained only 18.2% of the treatment effect on the biopsy score. In the diabetes setting, the estimated PTE of the surrogate marker was 0.596 (95% CI: 0.404, 0.760), that is, the surrogate explained 59.6% of the treatment effect on diabetes incidence.

CONCLUSIONS

This statistical workshop provides tools that will support future researchers in the evaluation of surrogate markers.

Prevalence and predictors of erectile dysfunction among men in the diabetes prevention program outcomes study

OBJECTIVE

To determine burden and identify correlates of erectile dysfunction (ED) among men with prediabetes (PreD) and type 2 diabetes (T2D) enrolled in the Diabetes Prevention Program (DPP) Outcomes Study (DPPOS).

RESEARCH DESIGN AND METHODS

The 2017 DPPOS visit included administration of the International Index of Erectile Function. Of 648 male participants, 88 % (n = 568) completed the survey. Associations between sociodemographic, behavioral, clinical, and glycemic measures at time of ED assessment, and ED were examined using multivariable logistic regression models in men with PreD and T2D separately.

RESULTS

Overall, 218 (38 %) men met ED criteria. Prevalence was similar in men with PreD (41 %) and T2D (37 %) (p = 0.4). In all men, age (p < 0.001) increased odds of ED. Among men with PreD, those assigned to intensive lifestyle intervention (ILS), but not metformin, had decreased odds of ED compared with the placebo group (OR = 0.35, 95 % CI = 0.13, 0.94). Non-Hispanic White race was associated with increased odds of ED compared with other races (OR = 4.3; 95 % CI = 1.92, 9.65). Among men with T2D, ED risk did not differ by DPP treatment assignment; however, individuals with metabolic syndrome defined by National Cholesterol Education Program criteria, had increased odds of ED (OR = 1.85, 95 % CI = 1.14, 3.01), as did individuals with depression (OR = 2.05; 95 % CI = 1.10, 3.79).

CONCLUSIONS

ED is prevalent in men with PreD and T2D. Our finding of reduced odds of ED in men randomized to ILS and with PreD suggests a potential opportunity for risk mitigation in the prediabetes interval. In men who have progressed to T2D, metabolic factors appear to be associated with ED.

MicroRNA biomarkers target genes and pathways associated with type 2 diabetes

AIMS/HYPOTHESIS

Our prior analysis of the Diabetes Prevention Program study identified a subset of five miRNAs that predict incident type 2 diabetes. The purpose of this study was to identify mRNAs and biological pathways targeted by these five miRNAs to elucidate potential mechanisms of risk and responses to the tested interventions.

METHODS

Using experimentally validated data from miRTarBase version 8.0 and R (2021), we identified mRNAs with strong evidence to be regulated by individual or combinations of the five predictor miRNAs. Overrepresentation of the mRNA targets was assessed in pathways from the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway annotation database.

RESULTS

The five miRNAs targeted 167 pathways and 122 mRNAs. Nine of the pathways have known associations with type 2 diabetes: Insulin signaling, Insulin resistance, Diabetic cardiomyopathy, Type 2 diabetes, AGE-RAGE signaling in diabetic complications, HIF-1 signaling, TGF-beta signaling, PI3K/Akt signaling, and Adipocytokine signaling pathways. Vascular endothelial growth factor A (VEGFA) has prior genetic associations with risk for type 2 diabetes and was the most commonly targeted mRNA for this set of miRNAs.

CONCLUSIONS/INTERPRETATION

These findings show that miRNA predictors of incident type 2 diabetes target mRNAs and pathways known to underlie risk for type 2 diabetes. Future studies should evaluate miRNAs as potential therapeutic targets for preventing and treating type 2 diabetes.

Identification of Genetic Variation Influencing Metformin Response in a Multiancestry Genome-Wide Association Study in the Diabetes Prevention Program (DPP)

Genome-wide significant loci for metformin response in type 2 diabetes reported elsewhere have not been replicated in the Diabetes Prevention Program (DPP). To assess pharmacogenetic interactions in prediabetes, we conducted a genome-wide association study (GWAS) in the DPP. Cox proportional hazards models tested associations with diabetes incidence in the metformin (MET; n = 876) and placebo (PBO; n = 887) arms. Multiple linear regression assessed association with 1-year change in metformin-related quantitative traits, adjusted for baseline trait, age, sex, and 10 ancestry principal components. We tested for gene-by-treatment interaction. No significant associations emerged for diabetes incidence. We identified four genome-wide significant variants after correcting for correlated traits (P < 9 × 10-9). In the MET arm, rs144322333 near ENOSF1 (minor allele frequency [MAF]AFR = 0.07; MAFEUR = 0.002) was associated with an increase in percentage of glycated hemoglobin (per minor allele, β = 0.39 [95% CI 0.28, 0.50]; P = 2.8 × 10-12). rs145591055 near OMSR (MAF = 0.10 in American Indians) was associated with weight loss (kilograms) (per G allele, β = -7.55 [95% CI -9.88, -5.22]; P = 3.2 × 10-10) in the MET arm. Neither variant was significant in PBO; gene-by-treatment interaction was significant for both variants [P(G×T) < 1.0 × 10-4]. Replication in individuals with diabetes did not yield significant findings. A GWAS for metformin response in prediabetes revealed novel ethnic-specific associations that require further investigation but may have implications for tailored therapy.

Genome-wide association analysis identifies ancestry-specific genetic variation associated with acute response to metformin and glipizide in SUGAR-MGH

AIMS/HYPOTHESIS

Characterisation of genetic variation that influences the response to glucose-lowering medications is instrumental to precision medicine for treatment of type 2 diabetes. The Study to Understand the Genetics of the Acute Response to Metformin and Glipizide in Humans (SUGAR-MGH) examined the acute response to metformin and glipizide in order to identify new pharmacogenetic associations for the response to common glucose-lowering medications in individuals at risk of type 2 diabetes.

METHODS

One thousand participants at risk for type 2 diabetes from diverse ancestries underwent sequential glipizide and metformin challenges. A genome-wide association study was performed using the Illumina Multi-Ethnic Genotyping Array. Imputation was performed with the TOPMed reference panel. Multiple linear regression using an additive model tested for association between genetic variants and primary endpoints of drug response. In a more focused analysis, we evaluated the influence of 804 unique type 2 diabetes- and glycaemic trait-associated variants on SUGAR-MGH outcomes and performed colocalisation analyses to identify shared genetic signals.

RESULTS

Five genome-wide significant variants were associated with metformin or glipizide response. The strongest association was between an African ancestry-specific variant (minor allele frequency [MAFAfr]=0.0283) at rs149403252 and lower fasting glucose at Visit 2 following metformin (p=1.9×10-9); carriers were found to have a 0.94 mmol/l larger decrease in fasting glucose. rs111770298, another African ancestry-specific variant (MAFAfr=0.0536), was associated with a reduced response to metformin (p=2.4×10-8), where carriers had a 0.29 mmol/l increase in fasting glucose compared with non-carriers, who experienced a 0.15 mmol/l decrease. This finding was validated in the Diabetes Prevention Program, where rs111770298 was associated with a worse glycaemic response to metformin: heterozygous carriers had an increase in HbA1c of 0.08% and non-carriers had an HbA1c increase of 0.01% after 1 year of treatment (p=3.3×10-3). We also identified associations between type 2 diabetes-associated variants and glycaemic response, including the type 2 diabetes-protective C allele of rs703972 near ZMIZ1 and increased levels of active glucagon-like peptide 1 (GLP-1) (p=1.6×10-5), supporting the role of alterations in incretin levels in type 2 diabetes pathophysiology.

CONCLUSIONS/INTERPRETATION

We present a well-phenotyped, densely genotyped, multi-ancestry resource to study gene-drug interactions, uncover novel variation associated with response to common glucose-lowering medications and provide insight into mechanisms of action of type 2 diabetes-related variation.

DATA AVAILABILITY

The complete summary statistics from this study are available at the Common Metabolic Diseases Knowledge Portal ( https://hugeamp.org ) and the GWAS Catalog ( www.ebi.ac.uk/gwas/ , accession IDs: GCST90269867 to GCST90269899).

The long-term effects of Kerala Diabetes Prevention Program on diabetes incidence and cardiometabolic risk: a study protocol

INTRODUCTION

India currently has more than 74.2 million people with Type 2 Diabetes Mellitus (T2DM). This is predicted to increase to 124.9 million by 2045. In combination with controlling blood glucose levels among those with T2DM, preventing the onset of diabetes among those at high risk of developing it is essential. Although many diabetes prevention interventions have been implemented in resource-limited settings in recent years, there is limited evidence about their long-term effectiveness, cost-effectiveness, and sustainability. Moreover, evidence on the impact of a diabetes prevention program on cardiovascular risk over time is limited.

OBJECTIVES

The overall aim of this study is to evaluate the long-term cardiometabolic effects of the Kerala Diabetes Prevention Program (K-DPP). Specific aims are 1) to measure the long-term effectiveness of K-DPP on diabetes incidence and cardiometabolic risk after nine years from participant recruitment; 2) to assess retinal microvasculature, microalbuminuria, and ECG abnormalities and their association with cardiometabolic risk factors over nine years of the intervention; 3) to evaluate the long-term cost-effectiveness and return on investment of the K-DPP; and 4) to assess the sustainability of community engagement, peer-support, and other related community activities after nine years.

METHODS

The nine-year follow-up study aims to reach all 1007 study participants (500 intervention and 507 control) from 60 randomized polling areas recruited to the original trial. Data are being collected in two phases. In phase 1 (Survey), we are admintsering a structured questionnaire, undertake physical measurements, and collect blood and urine samples for biochemical analysis. In phase II, we are inviting participants to undergo retinal imaging, body composition measurements, and ECG. All data collection is being conducted by trained Nurses. The primary outcome is the incidence of T2DM. Secondary outcomes include behavioral, psychosocial, clinical, biochemical, and retinal vasculature measures. Data analysis strategies include a comparison of outcome indicators with baseline, and follow-up measurements conducted at 12 and 24 months. Analysis of the long-term cost-effectiveness of the intervention is planned.

DISCUSSION

Findings from this follow-up study will contribute to improved policy and practice regarding the long-term effects of lifestyle interventions for diabetes prevention in India and other resource-limited settings.

TRIAL REGISTRATION

Australia and New Zealand Clinical Trials Registry-(updated from the original trial)ACTRN12611000262909; India: CTRI/2021/10/037191.

A Systematic Review of Behavioral Interventions on Children at Risk for Diabetes

INTRODUCTION

In adults, behavioral-based interventions support prevention of Type 2 diabetes; less is known in children. The aim of this systematic review was to examine the impact of behavioral-based interventions on cardiometabolic outcomes among children at risk for diabetes.

METHODS

PubMed, CINAHL Plus with Full Text, PsycINFO, and Web of Science were searched between September 2011 and September 2021. RCTs in children aged 6-12 years at risk for Type 2 diabetes that implemented a behavioral-based intervention and included ≥1 cardiometabolic outcome were eligible. If reported, dietary quality data were extracted. Risk of bias was assessed using the revised Cochrane risk-of-bias tool.

RESULTS

Of the 2,386 records identified, 4 met the inclusion criteria. Study length ranged from 10 weeks to 24 months, with sample sizes ranging from 53 to 113 participants. Among the 4 studies, there were 5 behavioral-based arms. All studies included weight status outcomes, with 3 finding significant between-group differences. Four studies assessed fasting glucose, and 3 assessed HbA1c; none found significant changes between groups. Of the 4 studies reporting blood pressure outcomes, 1 found a significant between-group difference for systolic blood pressure. Three studies assessed cholesterol and found no changes. No studies reported measures of dietary quality. All studies had some concerns about risk of bias.

DISCUSSION

Behavioral-based interventions improved weight status and supported the maintenance of cardiometabolic parameters. Stronger consideration of the most important risk factors in children along with intermediate outcomes (e.g., diet quality) may help to elucidate the relationship between behavioral-based interventions and cardiometabolic outcomes.

MicroRNAs Associated with Incident Diabetes in the Diabetes Prevention Program

OBJECTIVE

MicroRNAs (miRs) are short (i.e., 18-26 nucleotide) regulatory elements of messenger RNA translation to amino acids. The purpose of this study was to assess whether miRs are predictive of incident T2D in the Diabetes Prevention Program (DPP) trial.

RESEARCH DESIGN AND METHODS

This was a secondary analysis (n = 1,000) of a subset of the DPP cohort that leveraged banked biospecimens to measure miRs. We used random survival forest and Lasso to identify the optimal miR predictors and cox proportional hazards to model time to T2D overall and within intervention arms.

RESULTS

We identified five miRs (miR-144, miR-186, miR-203a, miR-205, miR-206) that constituted the optimal predictors of incident T2D after adjustment for covariates (hazards ratio 2.81 (95% confidence interval (CI) 2.05, 3.87); p < 0.001). Predictive risk scores following cross-validation showed the HR for the highest quartile risk group compared to the lowest quartile risk group was 5.91 (95% CI (2.02, 17.3); p < 0.001). There was significant interaction between the intensive lifestyle (HR 3.60, 95% CI (2.50, 5.18); p < 0.001) and the metformin (HR 2.72; 95% CI (1.47, 5.00); p = 0.001) groups compared to placebo. Of the five miRs identified, one targets a gene with prior known associations with risk for T2D.

DISCUSSION

We identified five miRs that are optimal predictors of incident T2D in the DPP cohort. Future directions include validation of this finding in an independent sample in order to determine whether this risk score may have potential clinical utility for risk stratification of individuals with prediabetes, and functional analysis of the potential genes and pathways targeted by the miRs that were included in the risk score.

Correlations between the Changing Levels of Tissue Plasminogen Activator and Adiposity Following Exercise-Induced Weight Loss

Cardiovascular disease is a major threat to global public health. Tissue plasminogen activator (TPA) is a serine protease that dissolves blood clots, which can also lead to excessive bleeding. Fibrinogen (FIBR), a glycoprotein, is converted by thrombin to fibrin and then to a fibrin-based blood clot. Both TPA and FIBR levels in the blood are associated with an increased risk of coronary heart disease, and the levels of the two factors are also positively correlated with total adipose tissue amounts. Visceral and subcutaneous adipose tissues (VAT and SAT) can contribute differently to whole-body metabolism. In this study, we sought to assess: (1) the strength of the correlation between the changing levels of the two factors and the changing amounts of VAT/SAT during exercise-induced weight loss, (2) whether there is any difference between the two types of adipose tissues in terms of the correlation, and (3) which factor, TPA or FIBR, is more sensitive to changes in adiposity? For this study, we analyzed the data from the diabetes prevention program (DPP), in which the participants were divided into three groups, with one group undergoing a lifestyle change that involved maintaining a minimum of 7% weight loss with physical activity. We found that the basal amounts of VAT and SAT were correlated with TPA and FIBR levels. However, following weight loss, adiposity changes were strongly correlated with the changing levels of TPA, but not FIBR, for both men and women. Therefore, TPA, but not FIBR, is sensitive to changes in adiposity. Furthermore, regarding TPA, weight loss sensitized its correlation with SAT, but not VAT. This study shows how adipose tissues distinctively affect TPA and FIBR levels, two factors associated with cardiovascular disease and ischemic stroke.

Baseline characteristics of participants in the Pre-Diabetes Interventions and Continued Tracking to Ease-out Diabetes (Pre-DICTED) Program

OBJECTIVE

The Pre-Diabetes Interventions and Continued Tracking to Ease-out Diabetes (Pre-DICTED) Program is a diabetes prevention trial comparing the diabetes conversion rate at 3 years between the intervention group, which receives the incentivized lifestyle intervention program with stepwise addition of metformin, and the control group, which receives the standard of care. We describe the baseline characteristics and compare Pre-DICTED participants with other diabetes prevention trials cohort.

RESEARCH DESIGN AND METHODS

Participants were aged between 21 and 64 years, overweight (body mass index (BMI) ≥23.0 kg/m2), and had pre-diabetes (impaired fasting glucose (IFG) and/or impaired glucose tolerance (IGT)).

RESULTS

A total of 751 participants (53.1% women) were randomized. At baseline, mean (SD) age was 52.5 (8.5) years and mean BMI (SD) was 29.0 (4.6) kg/m2. Twenty-three per cent had both IFG and IGT, 63.9% had isolated IGT, and 13.3% had isolated IFG. Ethnic Asian Indian participants were more likely to report a family history of diabetes and had a higher waist circumference, compared with Chinese and Malay participants. Women were less likely than men to meet the physical activity recommendations (≥150 min of moderate-intensity physical activity per week), and dietary intake varied with both sex and ethnicity. Compared with other Asian diabetes prevention studies, the Pre-DICTED cohort had a higher mean age and BMI.

CONCLUSION

The Pre-DICTED cohort represents subjects at high risk of diabetes conversion. The study will evaluate the effectiveness of a community-based incentivized lifestyle intervention program in an urban Asian context.

The 2018 World Cancer Research Fund (WCRF)/American Institute for Cancer Research (AICR) score and diabetes risk in the Diabetes Prevention Program Outcomes Study (DPPOS)

BACKGROUND

The 2018 World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR) 3rd expert report highlights up-to-date Cancer Prevention Recommendations that may reduce burdens of many chronic diseases, including diabetes. This study examined if following a lifestyle that aligns with the recommendations - assessed via the 2018 WCRF/AICR Score - was associated with lower risk of type 2 diabetes in high-risk adults participating in the Diabetes Prevention Program Outcomes Study (DPPOS).

METHODS

The Diabetes Prevention Program (DPP) randomized adults at high risk for diabetes to receive a lifestyle intervention (ILS), metformin (MET) or a placebo (PLB) (mean: 3.2 years), with additional follow-up in DPPOS for 11 years (mean: 15 years total). 2018 WCRF/AICR Scores included seven components: body weight, physical activity, plant-based foods, fast foods, red and processed meat, sugar-sweetened beverages, and alcohol; the optional breastfeeding component was excluded. Scores ranged 0-7 points (with greater scores indicating greater alignment with the recommendations) and were estimated at years 0, 1, 5, 6, 9, and 15 (N=3,147). Fasting glucose and HbA1c were measured every six months and oral glucose tolerance tests were performed annually. Adjusted Cox proportional hazard ratios (HRs) and 95% confidence intervals (CIs) were used to examine the association of both Score changes from years 0-1 and time-dependent Score changes on diabetes risk through DPP and year 15.

RESULTS

Scores improved within all groups over 15 years (p<0.001); ILS Scores improved more than MET or PLB Scores after 1 year (p<0.001). For every 1-unit improvement from years 0-1, there was a 31% and 15% lower diabetes risk in ILS (95% CI: 0.56-0.84) and PLB (95% CI: 0.72-0.97) through DPP, and no significant association in MET. Associations were greatest among American Indian participants, followed by non-Hispanic White and Hispanic participants. Score changes from years 0-1 and time-dependent Score changes in ILS and PLB remained associated with lower risk through year 15.

CONCLUSIONS

Score improvements were associated with long-term, lower diabetes risk among high-risk adults randomized to ILS and PLB, but not MET. Future research should explore impact of the Score on cancer risk.

TRIAL REGISTRATION

Diabetes Prevention Program: NCT00004992 ; Diabetes Prevention Program Outcomes Study: NCT00038727.

The Role of Racial and Ethnic Factors in MicroRNA Expression and Risk for Type 2 Diabetes

Prior studies focused on circulating microRNAs and the risk for complex diseases have shown inconsistent findings. The majority of studies focused on European and East Asian racial or ethnic groups, however, ancestry was not typically reported. We evaluated the risk for type 2 diabetes as an exemplar to show that race and ethnic group may contribute to inconsistent validation of previous findings of associations with microRNAs.

Adiposity, related biomarkers, and type 2 diabetes after gestational diabetes: The Diabetes Prevention Program

OBJECTIVE

This study investigated associations of adiposity and adiposity-related biomarkers with incident type 2 diabetes (T2D) among parous women.

METHODS

Among women in the Diabetes Prevention Program (DPP) who reported a previous live birth, circulating biomarkers (leptin, adiponectin, sex hormone-binding globulin, and alanine aminotransferase; n = 1,711) were measured at enrollment (average: 12 years post partum). Visceral (VAT) and subcutaneous adipose tissue areas at the L2-L3 region and the L3-L4 region were quantified by computed tomography (n = 477). Overall and stratified (by history of gestational diabetes mellitus [GDM]) adjusted Cox proportional hazards models were fit.

RESULTS

Alanine aminotransferase, L2-L3 VAT, and L3-L4 VAT were positively associated (hazard ratio [HR] for 1-SD increases: 1.073, p = 0.024; 1.251, p = 0.009; 1.272, p = 0.004, respectively), and adiponectin concentration was inversely associated with T2D (HR 0.762, p < 0.001). Whereas leptin concentration was not associated with T2D overall, in GDM-stratified models, a 1-SD higher leptin was positively associated with risk of T2D in women without GDM (HR: 1.126, p = 0.016) and inversely in women with a history of GDM (HR: 0.776, p = 0.013, interaction p = 0.002).

CONCLUSIONS

Among parous women, alanine aminotransferase and VAT are positively associated with incident T2D, whereas adiponectin is inversely associated. Leptin is associated with higher risk of T2D in women with a history of GDM but a lower risk in women without a history of GDM.

Temporal trends of concentrations of per- and polyfluoroalkyl substances among adults with overweight and obesity in the United States: Results from the Diabetes Prevention Program and NHANES

BACKGROUND

Understanding the temporal trends and change of concentrations of per- and polyfluoroalkyl substances (PFAS) is important to evaluate the health impact of PFAS at both the individual- and population-level, however, limited information is available for pre-diabetic adults in the U.S.

OBJECTIVES

Determine trends and rate of change of plasma PFAS concentrations in overweight or obese U.S. adults and evaluate variation by sex, race/ethnicity, and age.

METHODS

We described temporal trends of plasma PFAS concentrations using samples collected in 1996-1998, 1999-2001, and 2011-2012 from 957 pre-diabetic adults enrolled in the Diabetes Prevention Program (DPP) trial and Outcomes Study (DPPOS) and compared to serum concentrations from the National Health and Nutrition Examination Survey (NHANES 1999-2000, 2003-2016, adults with BMI ≥ 24 kg/m²). We examined associations between participants' characteristics and PFAS concentrations and estimated the rate of change using repeated measures in DPP/DPPOS assuming a first-order elimination model.

RESULTS

Longitudinal measures of PFAS concentrations in DPP/DPPOS individuals were comparable to NHANES cross-sectional populational means. Plasma concentrations of perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid, perfluorohexanesulfonic acid (PFHxS), N-ethyl-perfluorooctane sulfonamido acetic acid (EtFOSAA), and N-methylperfluorooctane sulfonamido acetic acid (MeFOSAA) started to decline after the year 2000 and concentrations of perfluorononanoic acid (PFNA) increased after 2000 and, for NHANES, decreased after 2012. We consistently observed higher PFOS, PFHxS and PFNA among male, compared to female, and higher PFOS and PFNA among Black, compared to white, participants. The estimated time for concentrations to decrease by half ranged from 3.39 years for EtFOSAA to 17.56 years for PFHxS.

DISCUSSION

We observed a downward temporal trend in plasma PFOS concentrations that was consistent with the timing for U.S. manufacturers' phaseout. Male and Black participants consistently showed higher PFOS and PFNA than female and white participants, likely due to differences in exposure patterns, metabolism or elimination kinetics.

Perceived Discrimination, Retention, and Diabetes Risk Among American Indians and Alaska Natives in a Diabetes Lifestyle Intervention

Objectives: To examine the association of perceived discrimination with participant retention and diabetes risk among American Indians and Alaska Natives. Methods: Data were drawn from the Special Diabetes Program for Indians-Diabetes Prevention Demonstration Project (N = 2553). Results: Perceived discrimination was significantly and negatively associated with short-term and long-term retention and diabetes risk without adjusting. After controlling for socioeconomic characteristics and clinical outcomes, perceived discrimination was not associated with retention but was significantly associated with less improvement in body mass index (BMI) and high-density lipoprotein (HDL) cholesterol. Every unit increase in the perceived discrimination score was associated with 0.14 kg/m2 less BMI reduction (95% CI: [0.02, 0.26], p = 0.0183) and 1.06 mg/dl lower HDL at baseline (95% CI: [0.36, 1.76], p = 0.0028). Discussion: Among racialized groups, improving retention and health in lifestyle interventions may require investigating perceived discrimination and the broader context of structural racism and colonialism.

Protocol for a randomized controlled trial of pre-pregnancy lifestyle intervention to reduce recurrence of gestational diabetes: Gestational Diabetes Prevention/Prevención de la Diabetes Gestacional

BACKGROUND

Gestational diabetes mellitus (GDM) is associated with several maternal complications in pregnancy, including preeclampsia, preterm labor, need for induction of labor, and cesarean delivery as well as increased long-term risks of type 2 diabetes, metabolic syndrome, and cardiovascular disease. Intrauterine exposure to GDM raises the risk for complications in offspring as well, including stillbirth, macrosomia, and birth trauma, and long-term risk of metabolic disease. One of the strongest risk factors for GDM is the occurrence of GDM in a prior pregnancy. Preliminary data from epidemiologic and bariatric surgery studies suggest that reducing body weight before pregnancy can prevent the development of GDM, but no adequately powered trial has tested the effects of a maternal lifestyle intervention before pregnancy to reduce body weight and prevent GDM recurrence.

METHODS

The principal aim of the Gestational Diabetes Prevention/Prevención de la Diabetes Gestacional is to determine whether a lifestyle intervention to reduce body weight before pregnancy can reduce GDM recurrence. This two-site trial targets recruitment of 252 women with overweight and obesity who have previous histories of GDM and who plan to have another pregnancy in the next 1-3 years. Women are randomized within site to a comprehensive pre-pregnancy lifestyle intervention to promote weight loss with ongoing treatment until conception or an educational control group. Participants are assessed preconceptionally (at study entry, after 4 months, and at brief quarterly visits until conception), during pregnancy (at 26 weeks' gestation), and at 6 weeks postpartum. The primary outcome is GDM recurrence, and secondary outcomes include fasting glucose, biomarkers of cardiometabolic disease, prenatal and perinatal complications, and changes over time in weight, diet, physical activity, and psychosocial measures.

DISCUSSION

The Gestational Diabetes Prevention /Prevención de la Diabetes Gestacional is the first randomized controlled trial to evaluate the effects of a lifestyle intervention delivered before pregnancy to prevent GDM recurrence. If found effective, the proposed lifestyle intervention could lay the groundwork for shifting current treatment practices towards the interconception period and provide evidence-based preconception counseling to optimize reproductive outcomes and prevent GDM and associated health risks.

TRIAL REGISTRATION

ClinicalTrials.gov NCT02763150 . Registered on May 5, 2016.

Per- and polyfluoroalkyl substances and kidney function: Follow-up results from the Diabetes Prevention Program trial

Per- and polyfluoroalkyl substances (PFAS) are ubiquitously detected in populations worldwide and may hinder kidney function. The objective of the study was to determine longitudinal associations of plasma PFAS concentrations with estimated glomerular filtration rate (eGFR) and evaluate whether a lifestyle intervention modify the associations. We studied 875 participants initially randomized to the lifestyle or placebo arms in the Diabetes Prevention Program (DPP, 1996-2002) trial and Outcomes Study (DPPOS, 2002-2014). We ran generalized linear mixed models accounting a priori covariates to evaluate the associations between baseline PFAS concentrations and repeated measures of eGFR, separately, for six PFAS (PFOS, PFOA, PFHxS, EtFOSAA, MeFOSAA, PFNA); then used quantile-based g-computation to evaluate the effects of the six PFAS chemicals as a mixture. The cohort was 64.9% female; 73.4% 40-64 years-old; 29.4% with hypertension; 50.5% randomized to lifestyle intervention and 49.5% to placebo and had similar plasma PFAS concentrations as the general U.S. population in 1999-2000. Most participants had normal kidney function (eGFR > 90 mL/min/1.73 m²) over the approximately 14 years of follow-up. We found that plasma PFAS concentrations during DPP were inversely associated with eGFR during DPPOS follow-up. Each quartile increase in baseline plasma concentration of the 6 PFAS as a mixture was associated with 2.26 mL/min/1.73 m² lower eGFR (95% CI: -4.12, -0.39) at DPPOS Year 5, approximately 9 years since DPP randomization and PFAS measurements. The lifestyle intervention did not modify associations, but inverse associations were stronger among participants with hypertension at baseline. Among prediabetic adults, we found inverse associations between baseline plasma PFAS concentrations and measures of eGFR throughout 14 years of follow-up. The lifestyle intervention of diet, exercise and behavioral changes did not modify the associations, but persons with hypertension may have heightened susceptibility.

Predictive utilities of lipid traits, lipoprotein subfractions and other risk factors for incident diabetes: a machine learning approach in the Diabetes Prevention Program

INTRODUCTION

Although various lipid and non-lipid analytes measured by nuclear magnetic resonance (NMR) spectroscopy have been associated with type 2 diabetes, a structured comparison of the ability of NMR-derived biomarkers and standard lipids to predict individual diabetes risk has not been undertaken in larger studies nor among individuals at high risk of diabetes.

RESEARCH DESIGN AND METHODS

Cumulative discriminative utilities of various groups of biomarkers including NMR lipoproteins, related non-lipid biomarkers, standard lipids, and demographic and glycemic traits were compared for short-term (3.2 years) and long-term (15 years) diabetes development in the Diabetes Prevention Program, a multiethnic, placebo-controlled, randomized controlled trial of individuals with pre-diabetes in the USA (N=2590). Logistic regression, Cox proportional hazards model and six different hyperparameter-tuned machine learning algorithms were compared. The Matthews Correlation Coefficient (MCC) was used as the primary measure of discriminative utility.

RESULTS

Models with baseline NMR analytes and their changes did not improve the discriminative utility of simpler models including standard lipids or demographic and glycemic traits. Across all algorithms, models with baseline 2-hour glucose performed the best (max MCC=0.36). Sophisticated machine learning algorithms performed similarly to logistic regression in this study.

CONCLUSIONS

NMR lipoproteins and related non-lipid biomarkers were associated but did not augment discrimination of diabetes risk beyond traditional diabetes risk factors except for 2-hour glucose. Machine learning algorithms provided no meaningful improvement for discrimination compared with logistic regression, which suggests a lack of influential latent interactions among the analytes assessed in this study.

TRIAL REGISTRATION NUMBER

Diabetes Prevention Program: NCT00004992; Diabetes Prevention Program Outcomes Study: NCT00038727.

Per- and polyfluoroalkyl substance plasma concentrations and metabolomic markers of type 2 diabetes in the Diabetes Prevention Program trial

BACKGROUND

Per- and polyfluoroalkyl substances (PFAS) are widely used chemicals, some of which have been linked to type 2 diabetes. We tested whether PFAS concentrations were cross-sectionally associated with metabolites previously shown to predict incident type 2 diabetes using the Diabetes Prevention Program (DPP), a trial of individuals at high risk of type 2 diabetes.

METHODS

We evaluated 691 participants enrolled in the DPP with baseline measures of 10 PFAS (including total perfluorooctanesulfonic acid (PFOS), total perfluorooctanoic acid (PFOA), and Sb-PFOA [branched isomers of PFOA]) and 77 metabolites. We used log2-transformed PFAS concentrations as exposures and standardized metabolite concentrations as outcomes in linear regression models adjusted for age, sex, race/ethnicity, use of anti-hyperlipidemic or triglyceride-lowering medication, income, years of education, marital status, smoking, and family history of diabetes, with Benjamini-Hochberg linear step-up false discovery rate correction.

RESULTS

Sb-PFOA was associated with the largest number of tested metabolites (29 of 77). Each doubling in Sb-PFOA was associated with higher leucine (β = 0.07 [95%CI: 0.02, 0.11] SD) and lower glycine (-0.08 [95%CI: 0.03, -0.13] SD). Each doubling of either total PFOA or n-PFOA was associated with -0.13 [95%CI: 0.04, -0.22] SD lower glycine. PFOA and Sb-PFOA were positively associated with multiple triacylglycerols and diacylglycerols, and total PFOS, total PFOA, and Sb-PFOA were positively associated with phosphatidylethanolamines.

CONCLUSIONS

PFAS concentrations are associated with metabolites linked to type 2 diabetes (particularly amino acid, glycerolipid and glycerophospholipid pathways). Further prospective research is needed to test whether these metabolites mediate associations of PFAS and type 2 diabetes.

The Relationship between Body Mass Index and Incident Diabetes Mellitus in Chinese Aged Population: A Cohort Study

OBJECTIVES

Previous studies reported that overweight older adults had a lower mortality after cardiovascular diseases attack, indicating being thinner might not always be better. However, there is an ongoing debate about what is the optimal range of body mass index (BMI) for the aged population. We aimed to evaluate the value of BMI for the prediction of incident diabetes mellitus (DM) in the Chinese elderly population.

METHODS

A total number of 6,911 Chinese elderly people (4,110 men and 2,801 women, aged 71 ± 6.0 years) were included in this cohort study. BMI was measured at baseline (Jan 1, 2014, to Dec 31, 2014). All the participants were further classified into six groups: <18.5 kg/m², 18.5 to <22.5 kg/m², 22.5 to <25.0 kg/m², 25.0 to <27.5 kg/m², 27.5 to <30.0 kg/m², and ≥30.0 kg/m². Fasting blood glucose (FBG) and glycated hemoglobin A1c (HbA1c) were annually measured during follow-up (Jan 1, 2015-May 31, 2019). DM was confirmed if either FBG ≥ 7.0 mmol/L or HbA1c ≥ 6.5%. We used the Cox proportional hazard regression model to evaluate the association between BMI and the prediction of incident DM.

RESULTS

Comparing individuals with a BMI range of 18.5 to <22.5 kg/m² (reference), the hazard ratio for incident DM was 2.13 (95% CI: 1.54~2.95), 2.14 (95% CI: 1.53~3.00), 3.17 (95% CI: 2.19~4.59), 3.15 (95% CI: 1.94~5.09), and 3.14 (95% CI: 1.94~5.09) for the group with a BMI range of 22.5 to <25.0 kg/m², 25.0 to <27.5 kg/m², 27.5 to <30.0 kg/m², and ≥30.0 kg/m² after adjusting for baseline age, sex, blood pressure, lipid profiles, and eGFR (P trend < 0.001), after adjusting for the abovementioned confounders. The association tended to be closer in men and young participants, compared with their counterparts.

CONCLUSIONS

High BMI was associated with a high risk of developing DM in the Chinese aged population. Thus, it is optimal for the aged population to maintain their body weight within a reasonable range to prevent chronic diseases.

Is there cardiac autonomic neuropathy in prediabetes?

Although there is considerably more data showing an association between type 2 diabetes mellitus (T2DM) and autonomic neuropathy, accumulating evidence indicates that cardiovascular autonomic neuropathy (CAN) is common in persons with impaired glucose tolerance (IGT). Furthermore, CAN may occur early after a metabolic insult and obesity, especially among mean, and seems to play an important role in the early pathogenesis of CAN. Autonomic symptoms are common in subjects with IGT. In addition to defects in CAN, in subjects with IGT, there is impaired sudomotor function and abnormalities of endothelial peripheral vasoreactivity. At the present time, the only interventions that may be effective in preventing or reversing IGT associated autonomic neuropathy are lifestyle improvement. These include a tailored diet and exercise program. Other approaches that may be beneficial include modulation of oxidative stress and improvement of metabolic regulation in subjects with IGT. Interventions are most likely to be effective early in the course of disease and therefore it is extremely important to have early diagnosis of IGT and autonomic neuropathy.

Revising Diabetes Programming for Black Men and Their Families

Type-2 diabetes has increased 160% for African American males in the United States. This two-part study's purpose was to apply social marketing theory to understand the Type-2 diabetes education needs of men in Iowa. Study One was a preference assessment of Type-2 diabetes education strategies. Four African American men participated in a series of four focus groups and indicated that they were interested in diabetes prevention programming with their families but not in having it labeled as diabetes education. Participating men would rather increase their physical activity as opposed to tracking their food intake. As a follow-up to this study, nine other African American males took part in Study Two, which used cooking demonstrations and recipe taste-testing with the men to examine their relationship to food in the context of managing their Type-2 diabetes. The findings of both studies, which provided insight into these African American men's lifestyle as related to their Type-2 diabetes, could be useful for nursing professionals who have a critical role in navigating cultural, gender, and family norms while developing care plans, offering patient education, and promoting quality of life.

Investigation of geographic disparities of pre-diabetes and diabetes in Florida

BACKGROUND

Diabetes is a leading cause of death and disability in the United States, and its precursor, pre-diabetes, is estimated to occur in one-third of American adults. Understanding the geographic disparities in the distribution of these conditions and identifying high-prevalence areas is critical to guiding control and prevention programs. Therefore, the objective of this study was to investigate clusters of pre-diabetes and diabetes risk in Florida and identify significant predictors of the conditions.

METHODS

Data from the 2013 Behavioral Risk Factor Surveillance System were obtained from the Florida Department of Health. Spatial scan statistics were used to identify and locate significant high-prevalence local clusters. The county prevalence proportions of pre-diabetes and diabetes and the identified significant clusters were displayed in maps. Logistic regression was used to identify significant predictors of the two conditions for individuals living within and outside high-prevalence clusters.

RESULTS

The study included a total of 34,186 respondents. The overall prevalence of pre-diabetes and diabetes were 8.2 and 11.5%, respectively. Three significant (p < 0.05) local, high-prevalence spatial clusters were detected for pre-diabetes, while five were detected for diabetes. The counties within the high-prevalence clusters had prevalence ratios ranging from 1.29 to 1.85. There were differences in the predictors of the conditions based on whether respondents lived within or outside high-prevalence clusters. Predictors of both pre-diabetes and diabetes regardless of region or place of residence were obesity/overweight, hypertension, and hypercholesterolemia. Income and physical activity level were significant predictors of diabetes but not pre-diabetes. Arthritis, sex, and marital status were significant predictors of diabetes only among residents of high-prevalence clusters, while educational attainment and smoking were significant predictors of diabetes only among residents of non-cluster counties.

CONCLUSIONS

Geographic disparities of pre-diabetes and diabetes exist in Florida. Information from this study is useful for guiding resource allocation and targeting of intervention programs focusing on identified modifiable predictors of pre-diabetes and diabetes so as to reduce health disparities and improve the health of all Floridians.

Lifestyle Changes Observed among Adults Participating in a Family- and Community-Based Intervention for Diabetes Prevention in Europe: The 1st Year Results of the Feel4Diabetes-Study

The Feel4Diabetes intervention was a school and community-based intervention aiming to promote healthy lifestyle and tackle obesity and obesity-related metabolic risk factors for the prevention of type 2 diabetes (T2D) among families at risk of developing this disease. The current study aims to present the results on lifestyle behaviors obtained from parents during the first year of the Feel4Diabetes intervention. This multicomponent intervention had a cluster randomized design and was implemented in Belgium, Bulgaria, Finland, Greece, Hungary and Spain over two years (2016-2018). Standardized protocols and procedures were used by the participating centers in all countries to collect data on parents' lifestyle behaviors (diet, physical activity, sedentary behavior). The Feel4Diabetes intervention was registered at clinicaltrials.gov (registration number: NCT02393872). In total, 2110 high-risk parents participated in the baseline and 12-month follow-up examination measurements. Participants allocated to the intervention group reduced their daily consumption of sugary drinks (p = 0.037) and sweets (p = 0.031) and their daily screen time (p = 0.032), compared with the control group. In addition, participants in the intervention group in Greece and Spain increased their consumption of breakfast (p = 0.034) and fruits (p = 0.029), while in Belgium and Finland they increased their water intake (p = 0.024). These findings indicate that the first year of the Feel4Diabetes intervention resulted in the improvement of certain lifestyle behaviors in parents from high-risk families.

Evidence generation, decision making, and consequent growth in health disparities

Evidence is valuable because it informs decisions to produce better outcomes. However, the same evidence that is complete for some individuals or groups may be incomplete for others, leading to inefficiencies in decision making and growth in disparities in outcomes. Specifically, the presence of treatment effect heterogeneity across some measure of baseline risk, and noisy information about such heterogeneity, can induce self-selection into randomized clinical trials (RCTs) by patients with distributions of baseline risk different from that of the target population. Consequently, average results from RCTs can disproportionately affect the treatment choices of patients with different baseline risks. Using economic models for these sequential processes of RCT enrollment, information generation, and the resulting treatment choice decisions, we show that the dynamic consequences of such information flow and behaviors may lead to growth in disparities in health outcomes across racial and ethnic categories. These disparities arise due to either the differential distribution of risk across those categories at the time RCT results are reported or the different rate of change of baseline risk over time across race and ethnicity, even though the distribution of risk within the RCT matched that of the target population when the RCT was conducted. We provide evidence on how these phenomena may have contributed to the growth in racial disparity in diabetes incidence.

Probiotics, prebiotics, and synbiotics supplementation in prediabetes: protocol for a systematic review and meta-analysis

BACKGROUND

The prevalence of prediabetes and diabetes is increasing rapidly, and 5% to 10% of prediabetic patients will develop diabetes every year. Diabetes causes major health problems as well as a large economic burden. Human studies have demonstrated the beneficial effects of probiotics, prebiotics, and synbiotics supplementation in prediabetes. However, there are no systematic reviews that explore the therapeutic efficacy of probiotics, prebiotics, and synbiotics supplementation in patients with prediabetes. Therefore, we aim to synthesize the existing evidence evaluating the effectiveness and safety of probiotics, prebiotics, and synbiotics supplementation in prediabetic patients.

METHODS

We will search PubMed, EMBASE, Cochrane Library, Web of Science, the Clinical Trials.gov website, China National Knowledge Infrastructure, China Science and Technology Journal Database, and Wanfang Data Knowledge Service Platform from inception to August 2020. Additionally, the search will be conducted in multiple languages. Search terms are keywords and medical subject headings related to prediabetes, probiotics, prebiotics, and synbiotics. The primary outcomes are differences in glycated hemoglobin and fasting blood glucose. The secondary outcomes are differences in fasting insulin, homeostasis model assessment of insulin resistance, quantitative insulin sensitivity check index, and adverse events. The meta-analysis will be performed using the Revman5.3.0 software provided by the Cochrane Collaboration.

RESULTS

Our study will systematically evaluate the effectiveness and safety of probiotics, prebiotics, and synbiotics supplementation in prediabetes.

CONCLUSION

The findings of this study will provide the best available evidence for probiotics, prebiotics, and synbiotics in the treatment of prediabetes, and provide a strong basis for clinical treatment.

Racial/ethnic differences in circulating natriuretic peptide levels: The Diabetes Prevention Program

Natriuretic peptides are cardiac-derived hormones that enhance insulin sensitivity and reduce fat accumulation. Low natriuretic peptide levels are associated with increased risk of type 2 diabetes mellitus (DM2); a condition with variable prevalence across racial/ethnic groups. Few studies have examined whether circulating natriuretic peptide levels and their response to preventive interventions for DM2 differ by race/ethnicity. The Diabetes Prevention Program (DPP) is a clinical trial (July 31, 1996- July 31, 2001) that randomized participants to preventive interventions for DM2. Using stored serum samples, we examined N-terminus pro-B-type natriuretic peptide (NT-proBNP) levels in 3,220 individuals (56% white; 19% African-American; 15% Hispanic; 5% American-Indian; 5% Asian). The influence of race/ethnicity on NT-proBNP concentrations at baseline and after two years of treatment with placebo, lifestyle, or metformin was examined with multivariable-adjusted regression. At baseline, NT-proBNP differed significantly by race (P < .001), with the lowest values in African-American individuals. Hispanic individuals also had lower baseline NT-proBNP levels compared with whites (P< .001), while NT-proBNP levels were similar between white, American-Indian, and Asian individuals. At two years of follow-up, NT-proBNP levels decreased in African-Americans in each of the DPP study arms, whereas they were stable or increased in the other racial/ethnic groups. In the DPP, African-American individuals had lower circulating NT-proBNP levels compared with individuals in other racial/ethnic groups at baseline and after two years of preventive interventions. Further studies should examine the cardio-metabolic implications of lower natriuretic peptide levels in African-Americans.

Trial Registration: ClinicalTrials.gov NCT00004992

Perceived barriers to physical activity during and after a behavioural weight loss programme

BACKGROUND

Most adults with overweight/obesity participating in behavioural weight loss (BWL) programmes never achieve prescribed physical activity (PA) levels. This study examined changes in PA barriers, their relationships with accelerometer-measured PA during and after a 12-month BWL programme, and associations between PA barriers and participant characteristics.

METHODS

Adults (N = 283) in a BWL programme completed the Barriers to Being Active Quiz, a 21-item self-report measure that assesses seven perceived PA barriers, and they wore an accelerometer for seven consecutive days at baseline and at 6 (midtreatment), 12 (end of treatment), 18 (6-mo follow-up), and 24 months (12-mo follow-up). Weight and height were measured, and demographic information was collected at baseline.

RESULTS

Repeated-measures analyses of variance (ANOVAs) revealed a significant quadratic effect of time on total PA barriers, P < .001, such that PA barriers decreased by midtreatment, remained below baseline levels by end of treatment, but increased to near-baseline levels by follow-up. Perceived PA barriers were negatively associated with baseline moderate-to-vigorous PA (MVPA), P < .001, and decreases in perceived PA barriers were related to greater MVPA at 6 (P = .004), 12 (P < .001), and 24 months (P = .007). Participants who were younger, P = .02, and white, P = .009, reported more baseline barriers.

CONCLUSIONS

Perceived PA barriers meaningfully decreased during BWL treatment, which in turn was associated with greater MVPA. This pattern suggests that, on average, BWL effectively addresses perceived PA barriers, which contributes to increased PA. Future research should identify interventions to maintain decreases in barriers after end of treatment.

Type 2 Diabetes and Atherosclerotic Cardiovascular Disease in South Asians: a Unique Population with a Growing Challenge

PURPOSE OF REVIEW

The purpose of this review is to summarize our current knowledge of factors that influence clinical decision making and management of type 2 diabetes mellitus (T2DM) and atherosclerotic cardiovascular disease (ASCVD) among South Asians (SA).

RECENT FINDINGS

ASCVD and T2DM in SAs have been examined in recent times. Pathophysiologic and genetic factors including the role of adiponectin, visceral adiposity, lower beta cell function, and psycho-social factors like sedentary lifestyle, poor adherence to medications, and carbohydrate dense meals play a role in early development and the high-risk presentation of both ASCVD and T2DM in SA. Recently, large population-based cohort studies have attempted to compare outcomes and interventions that can be translated to timely detection and targeted interventions in this high-risk group. SAs in the USA are more likely to be diagnosed with T2DM and ASCVD when compared to non-Hispanic whites, non-Hispanic Blacks, and Hispanic populations. The development of personalized ethnic risk assessment tools and better representation of SAs in prospective studies are essential to increasing our understanding and management of cardio-metabolic disease in SA living in the USA.

GDF-15 as a Weight Watcher for Diabetic and Non-Diabetic People Treated With Metformin

Weight gain and obesity are global health concerns contributing to morbidity with increased risks of cardiovascular disease, diabetes, liver steatohepatitis and cancer. Pharmacological therapies or bariatric surgery are often required for those who fail to adhere to diet and lifestyle modifications. Metformin, a widely used antidiabetic agent, seems to have a health benefit beyond its anti-hyperglycemic properties, with few side effects. Emerging evidence shows weight loss to be associated with metformin in both diabetic and non-diabetic individuals. Recently, the growth differentiation factor 15 (GDF-15), a member of the transforming growth factor beta superfamily, has been identified as a key mediator of metformin-induced weight loss. Metformin increases the secretion of GDF-15, which binds exclusively to glial cell-derived neurotrophic factor family receptor alpha-like (GFRAL). This gut-brain cytokine works as a prominent player in reducing food intake and body weight in health and disease, like anorexia nervosa and cancer. Herein, we critically review advances in the understanding of the weight-reducing effects of metformin via the GDF-15 pathway.

Interaction Between Type 2 Diabetes Prevention Strategies and Genetic Determinants of Coronary Artery Disease on Cardiometabolic Risk Factors

Coronary artery disease (CAD) is more frequent among individuals with dysglycemia. Preventive interventions for diabetes can improve cardiometabolic risk factors (CRFs), but it is unclear whether the benefits on CRFs are similar for individuals at different genetic risk for CAD. We built a 201-variant polygenic risk score (PRS) for CAD and tested for interaction with diabetes prevention strategies on 1-year changes in CRFs in 2,658 Diabetes Prevention Program (DPP) participants. We also examined whether separate lifestyle behaviors interact with PRS and affect changes in CRFs in each intervention group. Participants in both the lifestyle and metformin interventions had greater improvement in the majority of recognized CRFs compared with placebo (P < 0.001) irrespective of CAD genetic risk (P interaction > 0.05). We detected nominal significant interactions between PRS and dietary quality and physical activity on 1-year change in BMI, fasting glucose, triglycerides, and HDL cholesterol in individuals randomized to metformin or placebo, but none of them achieved the multiple-testing correction for significance. This study confirms that diabetes preventive interventions improve CRFs regardless of CAD genetic risk and delivers hypothesis-generating data on the varying benefit of increasing physical activity and improving diet on intermediate cardiovascular risk factors depending on individual CAD genetic risk profile.

Metformin for prevention or delay of type 2 diabetes mellitus and its associated complications in persons at increased risk for the development of type 2 diabetes mellitus

BACKGROUND

The projected rise in the incidence of type 2 diabetes mellitus (T2DM) could develop into a substantial health problem worldwide. Whether metformin can prevent or delay T2DM and its complications in people with increased risk of developing T2DM is unknown.

OBJECTIVES

To assess the effects of metformin for the prevention or delay of T2DM and its associated complications in persons at increased risk for the T2DM.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, MEDLINE, Scopus, ClinicalTrials.gov, the World Health Organization (WHO) International Clinical Trials Registry Platform and the reference lists of systematic reviews, articles and health technology assessment reports. We asked investigators of the included trials for information about additional trials. The date of the last search of all databases was March 2019.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) with a duration of one year or more comparing metformin with any pharmacological glucose-lowering intervention, behaviour-changing intervention, placebo or standard care in people with impaired glucose tolerance, impaired fasting glucose, moderately elevated glycosylated haemoglobin A1c (HbA1c) or combinations of these.

DATA COLLECTION AND ANALYSIS

Two review authors read all abstracts and full-text articles and records, assessed risk of bias and extracted outcome data independently. We used a random-effects model to perform meta-analysis and calculated risk ratios (RRs) for dichotomous outcomes and mean differences (MDs) for continuous outcomes, using 95% confidence intervals (CIs) for effect estimates. We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We included 20 RCTs randomising 6774 participants. One trial contributed 48% of all participants. The duration of intervention in the trials varied from one to five years. We judged none of the trials to be at low risk of bias in all 'Risk of bias' domains. Our main outcome measures were all-cause mortality, incidence of T2DM, serious adverse events (SAEs), cardiovascular mortality, non-fatal myocardial infarction or stroke, health-related quality of life and socioeconomic effects.The following comparisons mostly reported only a fraction of our main outcome set. Fifteen RCTs compared metformin with diet and exercise with or without placebo: all-cause mortality was 7/1353 versus 7/1480 (RR 1.11, 95% CI 0.41 to 3.01; P = 0.83; 2833 participants, 5 trials; very low-quality evidence); incidence of T2DM was 324/1751 versus 529/1881 participants (RR 0.50, 95% CI 0.38 to 0.65; P < 0.001; 3632 participants, 12 trials; moderate-quality evidence); the reporting of SAEs was insufficient and diverse and meta-analysis could not be performed (reported numbers were 4/118 versus 2/191; 309 participants; 4 trials; very low-quality evidence); cardiovascular mortality was 1/1073 versus 4/1082 (2416 participants; 2 trials; very low-quality evidence). One trial reported no clear difference in health-related quality of life after 3.2 years of follow-up (very low-quality evidence). Two trials estimated the direct medical costs (DMC) per participant for metformin varying from $220 to $1177 versus $61 to $184 in the comparator group (2416 participants; 2 trials; low-quality evidence). Eight RCTs compared metformin with intensive diet and exercise: all-cause mortality was 7/1278 versus 4/1272 (RR 1.61, 95% CI 0.50 to 5.23; P = 0.43; 2550 participants, 4 trials; very low-quality evidence); incidence of T2DM was 304/1455 versus 251/1505 (RR 0.80, 95% CI 0.47 to 1.37; P = 0.42; 2960 participants, 7 trials; moderate-quality evidence); the reporting of SAEs was sparse and meta-analysis could not be performed (one trial reported 1/44 in the metformin group versus 0/36 in the intensive exercise and diet group with SAEs). One trial reported that 1/1073 participants in the metformin group compared with 2/1079 participants in the comparator group died from cardiovascular causes. One trial reported that no participant died due to cardiovascular causes (very low-quality evidence). Two trials estimated the DMC per participant for metformin varying from $220 to $1177 versus $225 to $3628 in the comparator group (2400 participants; 2 trials; very low-quality evidence). Three RCTs compared metformin with acarbose: all-cause mortality was 1/44 versus 0/45 (89 participants; 1 trial; very low-quality evidence); incidence of T2DM was 12/147 versus 7/148 (RR 1.72, 95% CI 0.72 to 4.14; P = 0.22; 295 participants; 3 trials; low-quality evidence); SAEs were 1/51 versus 2/50 (101 participants; 1 trial; very low-quality evidence). Three RCTs compared metformin with thiazolidinediones: incidence of T2DM was 9/161 versus 9/159 (RR 0.99, 95% CI 0.41 to 2.40; P = 0.98; 320 participants; 3 trials; low-quality evidence). SAEs were 3/45 versus 0/41 (86 participants; 1 trial; very low-quality evidence). Three RCTs compared metformin plus intensive diet and exercise with identical intensive diet and exercise: all-cause mortality was 1/121 versus 1/120 participants (450 participants; 2 trials; very low-quality evidence); incidence of T2DM was 48/166 versus 53/166 (RR 0.55, 95% CI 0.10 to 2.92; P = 0.49; 332 participants; 2 trials; very low-quality evidence). One trial estimated the DMC of metformin plus intensive diet and exercise to be $270 per participant compared with $225 in the comparator group (94 participants; 1 trial; very-low quality evidence). One trial in 45 participants compared metformin with a sulphonylurea. The trial reported no patient-important outcomes. For all comparisons there were no data on non-fatal myocardial infarction, non-fatal stroke or microvascular complications. We identified 11 ongoing trials which potentially could provide data of interest for this review. These trials will add a total of 17,853 participants in future updates of this review.

AUTHORS' CONCLUSIONS

Metformin compared with placebo or diet and exercise reduced or delayed the risk of T2DM in people at increased risk for the development of T2DM (moderate-quality evidence). However, metformin compared to intensive diet and exercise did not reduce or delay the risk of T2DM (moderate-quality evidence). Likewise, the combination of metformin and intensive diet and exercise compared to intensive diet and exercise only neither showed an advantage or disadvantage regarding the development of T2DM (very low-quality evidence). Data on patient-important outcomes such as mortality, macrovascular and microvascular diabetic complications and health-related quality of life were sparse or missing.

Metabolite Profiles of Incident Diabetes and Heterogeneity of Treatment Effect in the Diabetes Prevention Program

Novel biomarkers of type 2 diabetes (T2D) and response to preventative treatment in individuals with similar clinical risk may highlight metabolic pathways that are important in disease development. We profiled 331 metabolites in 2,015 baseline plasma samples from the Diabetes Prevention Program (DPP). Cox models were used to determine associations between metabolites and incident T2D, as well as whether associations differed by treatment group (i.e., lifestyle [ILS], metformin [MET], or placebo [PLA]), over an average of 3.2 years of follow-up. We found 69 metabolites associated with incident T2D regardless of treatment randomization. In particular, cytosine was novel and associated with the lowest risk. In an exploratory analysis, 35 baseline metabolite associations with incident T2D differed across the treatment groups. Stratification by baseline levels of several of these metabolites, including specific phospholipids and AMP, modified the effect that ILS or MET had on diabetes development. Our findings highlight novel markers of diabetes risk and preventative treatment effect in individuals who are clinically at high risk and motivate further studies to validate these interactions.

Cluster Analysis of Unhealthy Lifestyles among Elderly Adults with Prediabetes: A Cross-Sectional Study in Rural China

INTRODUCTION

To explore the clustering and influencing factors of unhealthy lifestyles among elderly adults with prediabetes in rural China.

METHODS

A cross-sectional study was conducted in Yiyang, Hunan Province, China. Through multistage cluster random sampling and an oral glucose tolerance test, we screened 461 elderly adults aged 60 years and older with prediabetes out of 2144 elderly adults who were sampled. The prediabetic adults completed a survey examining four common lifestyle factors: diet, exercise, smoking, alcohol use and the ability to acquire diabetes-related knowledge and thereby promote one's own health-diabetes health literacy. The influencing factors were analyzed retrospectively with the Kruskal-Wallis test and ordinal logistic regression.

RESULTS

A total of 425 elderly adults completed the survey, of whom 325 were identified with unhealthy lifestyle clustering. The Kruskal-Wallis test showed significant differences between unhealthy lifestyle clusters by age, gender, marital status, occupation and hyperlipidemia (P < 0.05). Ordinal logistic regression showed that female gender (OR = 0.23, 95% CI: 0.15 0.37), personal annual income ≥ 2800 CNY (OR = 0.61, 95% CI: 0.38 0.99) and occupation as a worker (OR = 0.56, 95% CI: 0.34 0.92) were protective factors against unhealthy lifestyle clustering. An unsatisfactory marital status (OR = 1.60, 95% CI: 1.02 2.51) and low diabetes health literacy (OR = 3.17, 95% CI: 1.03 9.81) were risk factors.

CONCLUSION

In total, 76.47% of the prediabetic elderly adults in rural China showed unhealthy lifestyle clusters. Being male and having an unsatisfactory marital status, a low personal annual income, an occupation as a farmer and low diabetes health literacy were the main risk factors for unhealthy lifestyle clustering. More effective interventions should be implemented based on these risk factors to prevent diabetes in rural elderly adults.

Kahn S, Boyko EJ, Bray GA, Horton ES, Hivert MF, Goldberg R, Chen L, Mercader J, Harden M, Florez JC. A Polygenic Lipodystrophy Genetic Risk Score Characterizes Risk Independent of BMI in the Diabetes Prevention Program

CONTEXT

There is substantial heterogeneity in insulin sensitivity, and genetics may suggest possible mechanisms by which common variants influence this trait.

OBJECTIVES

We aimed to evaluate an 11-variant polygenic lipodystrophy genetic risk score (GRS) for association with anthropometric, glycemic and metabolic traits in the Diabetes Prevention Program (DPP). In secondary analyses, we tested the association of the GRS with cardiovascular risk factors in the DPP.

DESIGN

In 2713 DPP participants, we evaluated a validated GRS of 11 common variants associated with fasting insulin-based measures of insulin sensitivity discovered through genome-wide association studies that cluster with a metabolic profile of lipodystrophy, conferring high metabolic risk despite low body mass index (BMI).

RESULTS

At baseline, a higher polygenic lipodystrophy GRS was associated with lower weight, BMI, and waist circumference measurements, but with worse insulin sensitivity index (ISI) values. Despite starting at a lower weight and BMI, a higher GRS was associated with less weight and BMI reduction at one year and less improvement in ISI after adjusting for baseline values but was not associated with diabetes incidence. A higher GRS was also associated with more atherogenic low-density lipoprotein peak-particle-density at baseline but was not associated with coronary artery calcium scores in the Diabetes Prevention Program Outcomes Study.

CONCLUSIONS

In the DPP, a higher polygenic lipodystrophy GRS for insulin resistance with lower BMI was associated with diminished improvement in insulin sensitivity and potential higher cardiovascular disease risk. This GRS helps characterize insulin resistance in a cohort of individuals at high risk for diabetes, independent of adiposity.

Dynamic risk prediction for diabetes using biomarker change measurements

Background

Dynamic risk models, which incorporate disease-free survival and repeated measurements over time, might yield more accurate predictions of future health status compared to static models. The objective of this study was to develop and apply a dynamic prediction model to estimate the risk of developing type 2 diabetes mellitus.

Methods

Both a static prediction model and a dynamic landmark model were used to provide predictions of a 2-year horizon time for diabetes-free survival, updated at 1, 2, and 3 years post-baseline i.e., predicting diabetes-free survival to 2 years and predicting diabetes-free survival to 3 years, 4 years, and 5 years post-baseline, given the patient already survived past 1 year, 2 years, and 3 years post-baseline, respectively. Prediction accuracy was evaluated at each time point using robust non-parametric procedures. Data from 2057 participants of the Diabetes Prevention Program (DPP) study (1027 in metformin arm, 1030 in placebo arm) were analyzed.

Results

The dynamic landmark model demonstrated good prediction accuracy with area under curve (AUC) estimates ranging from 0.645 to 0.752 and Brier Score estimates ranging from 0.088 to 0.135. Relative to a static risk model, the dynamic landmark model did not significantly differ in terms of AUC but had significantly lower (i.e., better) Brier Score estimates for predictions at 1, 2, and 3 years (e.g. 0.167 versus 0.099; difference − 0.068 95% CI − 0.083 to − 0.053, at 3 years in placebo group) post-baseline.

Conclusions

Dynamic prediction models based on longitudinal, repeated risk factor measurements have the potential to improve the accuracy of future health status predictions.

Electronic supplementary material

The online version of this article (10.1186/s12874-019-0812-y) contains supplementary material, which is available to authorized users.

Long-Term Weight Loss With Metformin or Lifestyle Intervention in the Diabetes Prevention Program Outcomes Study

BACKGROUND

Identifying reliable predictors of long-term weight loss (LTWL) could lead to improved weight management.

OBJECTIVE

To identify some predictors of LTWL.

DESIGN

The DPP (Diabetes Prevention Program) was a randomized controlled trial that compared weight loss with metformin, intensive lifestyle intervention (ILS), or placebo. Its Outcomes Study (DPPOS) observed patients after the masked treatment phase ended. (ClinicalTrials.gov: NCT00004992 and NCT00038727).

SETTING

27 DPP and DPPOS clinics.

PARTICIPANTS

Of the 3234 randomly assigned participants, 1066 lost at least 5% of baseline weight in the first year and were followed for 15 years.

MEASUREMENTS

Treatment assignment, personal characteristics, and weight.

RESULTS

After 1 year, 289 (28.5%) participants in the metformin group, 640 (62.6%) in the ILS group, and 137 (13.4%) in the placebo group had lost at least 5% of their weight. After the masked treatment phase ended, the mean weight loss relative to baseline that was maintained between years 6 and 15 was 6.2% (95% CI, 5.2% to 7.2%) in the metformin group, 3.7% (CI, 3.1% to 4.4%) in the ILS group, and 2.8% (CI, 1.3% to 4.4%) in the placebo group. Independent predictors of LTWL included greater weight loss in the first year in all groups, older age and continued metformin use in the metformin group, older age and absence of either diabetes or a family history of diabetes in the ILS group, and higher fasting plasma glucose levels at baseline in the placebo group.

LIMITATION

Post hoc analysis; examination of nonrandomized subsets of randomized groups after year 1.

CONCLUSION

Among persons with weight loss of at least 5% after 1 year, those originally randomly assigned to metformin had the greatest loss during years 6 to 15. Older age and the amount of weight initially lost were the most consistent predictors of LTWL maintenance.

PRIMARY FUNDING SOURCE

National Institutes of Health.

Genetic Ancestry Markers and Difference in A1c Between African American and White in the Diabetes Prevention Program

PURPOSE

HbA1c levels are higher in blacks than non-Hispanic whites (NHWs). We investigated whether genetics could explain this difference in Diabetes Prevention Program (DPP) participants.

METHODS

We tested (i) genetic variants causing hemoglobinopathies, (ii) a genetic risk score (GRS) based on 60 variants associated with HbA1c from genome-wide association meta-analysis, and (iii) principal component (PC) factors that capture continental ancestry derived from genetic markers distributed across the genome.

RESULTS

Of 2658 eligible DPP participants, 537 (20%) self-identified as black and 1476 (56%) as NHW. Despite comparable fasting and 2-hour glucose levels, blacks had higher HbA1c (mean ± SD = 6.2 ± 0.6%) compared with NHWs (5.8 ± 0.4%; P < 0.001). In blacks, the genetic variant causing sickle cell trait was associated with higher HbA1c [β (SE) = +0.44 (0.08)%; P = 2.1 × 10-4]. The GRS was associated with HbA1c in both blacks and NHWs. Self-identified blacks were distributed along the first PC axis, as expected in mixed ancestry populations. The first PC explained 60% of the 0.4% difference in HbA1c between blacks and NHWs, whereas the sickle cell variant explained 16% and GRS explained 14%.

CONCLUSIONS

A large proportion of HbA1c difference between blacks and NHWs was associated with the first PC factor, suggesting that unidentified genetic markers influence HbA1c in blacks in addition to nongenetic factors.

Psychosocial and Behavioral Correlates of A1C and Quality of Life Among Young Adults With Diabetes

PURPOSE

The purpose of this study was to evaluate relationships between behavioral and psychosocial constructs, A1C, and diabetes-dependent quality of life (DQoL) among low-socioeconomic status, ethnically diverse young adults with diabetes.

METHODS

Using baseline data of 81 participants in the Resilient, Empowered, Active Living (REAL) randomized controlled trial, behavioral, cognitive, affective, and experiential variables were correlated with A1C and DQoL while adjusting for demographic characteristics, and these relationships were examined for potential effect modification.

RESULTS

The data indicate that depressive symptoms and satisfaction with daily activities are associated with both A1C and DQoL, while diabetes knowledge and participation in daily activities are associated with neither A1C nor DQoL. Two constructs, diabetes distress and life satisfaction, were associated with DQoL and were unrelated to A1C, while 2 constructs, self-monitoring of blood glucose and medication adherence, were associated with A1C but unrelated to DQoL. These relationships were largely unchanged by adjusting for demographic characteristics, while numerous effect modifications were found.

CONCLUSION

The data suggest that when tailoring interventions, depressive symptoms and satisfaction with daily activities may be particularly fruitful intervention targets, as they represent modifiable risk factors that are associated with both A1C and DQoL.

Effects of lifestyle changes on adults with prediabetes: A systematic review and meta-analysis

AIMS

To assess the efficacy, safety, and cost-effectiveness of lifestyle intervention, compared with treatment as usual in people with prediabetes as defined by the American Diabetes Association. For older studies, we used the 1985 World Health Organization definition.

METHODS

We systematically searched multiple electronic databases and referenced lists of pertinent review articles from January 1980 through November 2015. We performed an update search in MEDLINE on April 26, 2017. Based on a priori established eligibility criteria, we dually reviewed the literature, extracted data, and rated the risk of bias of included studies with validated checklists. To assess the efficacy of lifestyle intervention to prevent or delay further progression to type 2 diabetes, we conducted a random-effects meta-analysis. We assessed the certainty of evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) approach.

RESULT

Pooled results of 16 randomized controlled trials showed that people with prediabetes who received lifestyle intervention had a lower rate of progression to type 2 diabetes after one (4% vs. 10%, RR 0.46 [CI 0.32, 0.66]) and three years of follow-up (14% vs. 23%, RR 0.64 [95% CI 0.53, 0.77]). The majority of the studies also showed a greater weight loss in lifestyle intervention participants, with a great variation between studies. Costs per quality-adjusted life-year were lower when the benefits of lifestyle intervention were analyzed over a lifelong time horizon compared to only the period of lifestyle intervention (three years) or to modeling over a ten-year period.

CONCLUSION

Lifestyle intervention is an efficacious, safe, and cost-effective measure to reduce the risk of progression to type 2 diabetes in people diagnosed with prediabetes. More research is necessary to compare the efficacy of various modes, frequencies, and intensities of lifestyle intervention across studies.

Association of Perfluoroalkyl and Polyfluoroalkyl Substances With Adiposity

IMPORTANCE

Perfluoroalkyl and polyfluoroalkyl substances (PFASs) are ubiquitous synthetic chemicals that are suspected endocrine disruptors.

OBJECTIVES

To determine the extent to which PFASs are associated with increases in weight and body size and evaluate whether a lifestyle intervention modifies this association.

DESIGN, SETTING, AND PARTICIPANTS

This prospective cohort study included 957 individuals who participated in the Diabetes Prevention Program trial, conducted from July 1996 to May 2001, and the Diabetes Prevention Program Outcomes Study, conducted from September 2002 to January 2014. Statistical analysis was conducted from September 1, 2017, to May 25, 2018.

INTERVENTIONS AND EXPOSURES

The initial lifestyle intervention consisted of training in diet, physical activity, and behavior modification, with the major goals of achieving 7% weight loss with subsequent maintenance and a minimum of 150 minutes per week of physical activity. Participants randomized to placebo received standard information about diet and exercise. A total of 6 plasma PFASs were quantified at baseline and 2 years after randomization, means were calculated from baseline and year 2 concentrations, and means were summed to assess total PFAS burden.

MAIN OUTCOMES AND MEASURES

Weight, waist circumference, and hip girth were measured at baseline and at scheduled visits.

RESULTS

Of the 957 participants, 625 (65.3%) were women and 731 participants (76.4%) were between 40 and 64 years of age; 481 participants were randomized to the lifestyle intervention and 476 participants were randomized to the placebo arm. The PFAS concentrations were not different by treatment arm and were similar to concentrations reported for the US population in 1999-2000. The association of PFAS and weight change differed by treatment. Each doubling in total PFAS concentration was associated with an increase of 1.80 kg (95% CI, 0.43-3.17 kg; P = .01) from baseline to 9 years after randomization for the placebo group but not the lifestyle intervention group (-0.59 kg; 95% CI, -1.80 to 0.62 kg; P = .34). Similarly, each doubling in PFAS was associated with a 1.03-cm increase in hip girth in the Diabetes Prevention Program trial for the placebo group (95% CI, 0.18-1.88 cm; P = .02) but not the lifestyle intervention group (-0.09 cm; 95% CI, -0.82 to 0.63 cm; P = .80). No associations were observed for changes in mean waist circumference.

CONCLUSIONS AND RELEVANCE

Among adults at high risk for diabetes, higher plasma PFAS concentration was associated with increases in weight and hip girth over time, but a lifestyle intervention attenuated these associations. Diet and exercise may mitigate the obesogenic effects of environmental chemicals.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00004992 and NCT00038727.