Effects of Long-term Metformin and Lifestyle Interventions on Cardiovascular Events in the Diabetes Prevention Program and Its Outcome Study.

BACKGROUND: Lifestyle intervention and metformin have been shown to prevent diabetes; however, their efficacy in preventing cardiovascular disease associated with the development of diabetes is unclear. We examined whether these interventions reduced the incidence of major cardiovascular events over a 21-year median follow-up of participants in the DPP trial (Diabetes Prevention Program) and DPPOS (Diabetes Prevention Program Outcomes Study). METHODS: During DPP, 3234 participants with impaired glucose tolerance were randomly assigned to metformin 850 mg twice daily, intensive lifestyle or placebo, and followed for 3 years. During the next 18-year average follow-up in DPPOS, all participants were offered a less intensive group lifestyle intervention, and unmasked metformin was continued in the metformin group. The primary outcome was the first occurrence of nonfatal myocardial infarction, stroke, or cardiovascular death adjudicated by standard criteria. An extended cardiovascular outcome included the primary outcome or hospitalization for heart failure or unstable angina, coronary or peripheral revascularization, coronary heart disease diagnosed by angiography, or silent myocardial infarction by ECG. ECGs and cardiovascular risk factors were measured annually. RESULTS: Neither metformin nor lifestyle intervention reduced the primary outcome: metformin versus placebo hazard ratio 1.03 (95% CI, 0.78-1.37; P = 0.81) and lifestyle versus placebo hazard ratio 1.14 (95% CI, 0.87-1.50; P = 0.34). Risk factor adjustment did not change these results. No effect of either intervention was seen on the extended cardiovascular outcome. CONCLUSIONS: Neither metformin nor lifestyle reduced major cardiovascular events in DPPOS over 21 years despite long-term prevention of diabetes. Provision of group lifestyle intervention to all, extensive out-of-study use of statin and antihypertensive agents, and reduction in the use of study metformin together with out-of-study metformin use over time may have diluted the effects of the interventions. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifiers: DPP (NCT00004992) and DPPOS (NCT00038727).

HDL (High-Density Lipoprotein) Subclasses, Lipid Content, and Function Trajectories Across the Menopause Transition: SWAN-HDL Study.

OBJECTIVE: The cardioprotective capacity of HDL (high-density lipoprotein) cholesterol postmenopause has been challenged. HDL subclasses, lipid contents, and function might be better predictors of cardiovascular risk than HDL cholesterol. Changes in these measures have not been characterized over the menopause transition (MT) with respect to timing relative to the final menstrual period. Approach and Results: Four hundred seventy-one women with HDL particle (HDL-P) subclasses (nuclear magnetic resonance spectroscopy total, large, medium, and small HDL-P and HDL size), HDL lipid content (HDL phospholipids and triglycerides), and HDL function (cholesterol efflux capacity [HDL-CEC]) measured for a maximum of 5 time points across the MT were included. HDL cholesterol and total HDL-P increased across the MT. Within the 1 to 2 years bracketing the final menstrual period, large HDL-P and HDL size declined while small HDL-P and HDL-triglyceride increased. Although overall HDL-CEC increased across the MT, HDL-CEC per HDL-P declined. Higher concentrations of total, large, and medium HDL-P and greater HDL size were associated with greater HDL-CEC while of small HDL-P were associated with lower HDL-CEC. Associations of large HDL-P and HDL size with HDL-CEC varied significantly across the MT such that higher large HDL-P concentrations and greater HDL size were associated with lower HDL-CEC within the 1 to 2 years around the final menstrual period. CONCLUSIONS: Although HDL cholesterol increased over the MT, HDL subclasses and lipid content showed adverse changes. While overall HDL-CEC increased, HDL-CEC per HDL-P declined, consistent with reduced function per particle. Large HDL-P may become less efficient in promoting HDL-CEC during the MT.

Association of Coding Variants in Hydroxysteroid 17-beta Dehydrogenase 14 (HSD17B14) with Reduced Progression to End Stage Kidney Disease in Type 1 Diabetes.

BACKGROUND: Rare variants in gene coding regions likely have a greater impact on disease-related phenotypes than common variants through disruption of their encoded protein. We searched for rare variants associated with onset of ESKD in individuals with type 1 diabetes at advanced kidney disease stage. METHODS: Gene-based exome array analyses of 15,449 genes in five large incidence cohorts of individuals with type 1 diabetes and proteinuria were analyzed for survival time to ESKD, testing the top gene in a sixth cohort (n=2372/1115 events all cohorts) and replicating in two retrospective case-control studies (n=1072 cases, 752 controls). Deep resequencing of the top associated gene in five cohorts confirmed the findings. We performed immunohistochemistry and gene expression experiments in human control and diseased cells, and in mouse ischemia reperfusion and aristolochic acid nephropathy models. RESULTS: Protein coding variants in the hydroxysteroid 17-ß dehydrogenase 14 gene (HSD17B14), predicted to affect protein structure, had a net protective effect against development of ESKD at exome-wide significance (n=4196; P value=3.3 × 10-7). The HSD17B14 gene and encoded enzyme were robustly expressed in healthy human kidney, maximally in proximal tubular cells. Paradoxically, gene and protein expression were attenuated in human diabetic proximal tubules and in mouse kidney injury models. Expressed HSD17B14 gene and protein levels remained low without recovery after 21 days in a murine ischemic reperfusion injury model. Decreased gene expression was found in other CKD-associated renal pathologies. CONCLUSIONS: HSD17B14 gene is mechanistically involved in diabetic kidney disease. The encoded sex steroid enzyme is a druggable target, potentially opening a new avenue for therapeutic development.

Associations of HDL metrics with coronary artery calcium score and density among women traversing menopause.

The cardioprotective association of high-density lipoprotein cholesterol (HDL-C) may vary by menopause stage or estradiol level. We tested whether associations of comprehensive HDL metrics (HDL subclasses, phospholipid and triglyceride content, and HDL cholesterol efflux capacity [HDL-CEC]) with coronary artery calcium (CAC) score and density vary by menopause stage or estradiol level in women transitioning through menopause. Participants (N = 294; mean age [SD]: 51.3 [2.9]) had data on HDL metrics and CAC measures at one or two time points during the menopause transition. Generalized estimating equations were used for analyses. Effect modifications by menopause stage or estradiol level were tested in multivariable models. In adjusted models, menopause stage modified the associations of specific HDL metrics with CAC measures. Higher small HDL particles (HDL-P) concentrations (p-interaction = 0.008) and smaller HDL size (p-interaction = 0.02) were associated with greater odds of CAC presence in late perimenopause than in pre/early perimenopause stage. Women in the highest estradiol tertile, but not the lower tertiles, showed a protective association of small HDL-P with CAC presence (p-interaction = 0.007). Lower large HDL-P concentrations (p-interaction = 0.03) and smaller HDL size (p-interaction = 0.03) were associated with lower CAC density in late perimenopause than in postmenopause stage. Associations of HDL phospholipid and triglyceride content and HDL-CEC with CAC measures did not vary by menopause stage or estradiol level. We concluded that HDL subclasses may impact the likelihood of CAC presence and the stability of coronary plaque differently over the menopause transition. Endogenous estradiol levels may contribute to this observation.

Cardiovascular health in early adulthood predicts the development of coronary heart disease in individuals with type 1 diabetes: 25 year follow-up from the Pittsburgh Epidemiology of Diabetes Complications study.

AIMS/HYPOTHESIS: Type 1 diabetes increases CHD risk. We examined the use of the American Heart Association's cardiovascular health metrics (blood pressure, total cholesterol, glucose/HbA1c, BMI, physical activity, diet, smoking) to predict incidence of CHD among individuals with type 1 diabetes, with the hypothesis that a better American Heart Association health metric profile would be associated with lower incident CHD. METHODS: Prevalence of the seven cardiovascular health metrics was determined using first and second visits from adult participants (mean age 28.6 years) in the Epidemiology of Diabetes Complications prospective cohort study of childhood-onset type 1 diabetes. An ideal metric score (0-7) was defined as the sum of all metrics within the ideal range, and a total metric score (0-14) was calculated based on poor, intermediate and ideal categories for each metric. Incident CHD development (medical record-confirmed CHD death, myocardial infarction, revascularisation, ischaemic electrocardiogram changes or Epidemiology of Diabetes Complications physician-determined angina) over 25 years of follow-up was examined by metric scores. RESULTS: Among 435 participants, BMI, blood pressure, total cholesterol and smoking demonstrated the highest prevalence within the ideal range, while diet and HbA1c demonstrated the lowest. During 25 years of follow-up, 177 participants developed CHD. In Cox models, each additional metric within the ideal range was associated with a 19% lower risk (p = 0.01), and each unit increase in total metric score was associated with a 17% lower risk (p < 0.01) of CHD, adjusting for diabetes duration, estimated glomerular filtration rate, albumin excretion rate, triacylglycerols, depression and white blood cell count. CONCLUSIONS/INTERPRETATION: Among individuals with type 1 diabetes, higher cardiovascular health metric scores were associated with lower risk of incident CHD. The American Heart Association-defined cardiovascular health metrics provide straightforward goals for health promotion that may reduce CHD risk in the type 1 diabetes population. Graphical abstract.

Heterogeneous long-term trajectories of glycaemic control in type 1 diabetes.

AIMS: We aimed to identify long-term HbA1c trajectories and examine associated characteristics in an observational, childhood-onset (<17 years) type 1 diabetes cohort. METHODS: Data are from the Epidemiology of Diabetes Complications study, comprising 405 participants with ≥2 of seven possible HbA1c measurements over follow-up (1988-2013) and available DNA (baseline mean diabetes duration 21 years, 53% men). HbA1c trajectories were estimated using latent class growth models. Baseline and change in participant characteristics were compared across trajectories. RESULTS: Five HbA1c trajectories were identified: low (51%), intermediate stable (22%), improved (19%), high stable (6%), and worsened (2%; not included in analyses). Age, diabetes duration, diabetes onset age, and sex did not differ across trajectories. Characteristics did not differ significantly between intermediate stable and low trajectories at baseline, though albumin excretion rate (AER, p = 0.0002) and estimated glomerular filtration rate (eGFR, p = 0.001) worsened slightly more in intermediate stable over time. Improved and high stable trajectories had higher baseline LDL-c (p = 0.002 and 0.003, respectively). Improved trajectory increased median self-monitoring of blood glucose from <1 to 3.5 times/day (p < 0.0001) and had larger LDL-c improvement (p = 0.004) but greater worsening of AER (p < 0.0001) and eGFR (p < 0.0001) than low. The A allele of rs12970134 (near MC4R) was associated with improved (p = 0.0003) or high stable (p = 0.001) HbA1c trajectory, both patterns with high baseline HbA1c. CONCLUSIONS: Long-term HbA1c trajectories were primarily associated with modifiable factors in this type 1 diabetes cohort. The intermediate stable pattern had a risk factor profile that suggests some protection against adverse metabolic effects of chronic hyperglycaemia, warranting further study.

Muscle insulin resistance in type 1 diabetes with coronary artery disease.

AIMS/HYPOTHESIS: The risk for coronary artery disease (CAD) is substantially increased in type 1 diabetes and it has been postulated that insulin resistance may contribute to this risk. The current study measured insulin resistance in type 1 diabetes with vs without CAD and with a focus upon skeletal muscle, to test the hypothesis that insulin resistance is more severe in participants who have type 1 diabetes and CAD. Additionally, in type 1 diabetes, we examined the hypothesis that insulin resistance is more severe in soleus (an oxidative type muscle) vs tibialis anterior (a more glycolytic type of muscle). METHODS: Insulin resistance was measured in participants with type 1 diabetes with (n = 9, CAD+) and without CAD (n = 10, CAD-) using euglycaemic insulin infusions combined with positron emission tomography (PET) imaging of [18F]fluorodeoxyglucose (FDG) uptake into soleus and tibialis anterior skeletal muscles. Coronary artery calcium (CAC) score was quantified by electron beam tomography. RESULTS: CAD+ participants with type 1 diabetes had a >100-fold higher CAC score than did CAD- participants with type 1 diabetes but groups did not differ in HbA1c or insulin dose. During clamp studies, CAD+ and CAD- groups had similar glucose disposal but were insulin resistant compared with historical non-diabetic participants (n = 13). FDG uptake by soleus muscle was similarly reduced, overall, in individuals with type 1 diabetes with or without CAD compared with non-diabetic individuals. However, FDG uptake by tibialis anterior muscle was not reduced in CAD- participants with type 1 diabetes while in CAD+ participants with type 1 diabetes it was 75% greater (p < 0.01). Across all participants with type 1 diabetes, FDG uptake by tibialis anterior muscle correlated positively with CAC severity. CONCLUSIONS/INTERPRETATION: Our study confirms that systemic and skeletal muscle-specific insulin resistance is seen in type 1 diabetes but found that it does not appear to be more severe in the presence of CAD. There were, however, sharp differences between soleus and tibialis anterior muscles in type 1 diabetes: while insulin resistance was clearly manifest in soleus muscle, and was of equal severity in CAD+ and CAD- participants, tibialis anterior did not suggest insulin resistance in participants with type 1 diabetes, as FDG uptake by tibialis anterior correlated positively with CAC severity and was significantly increased in participants with type 1 diabetes and clinical CAD. Graphical abstract.

A Targeted Multiomics Approach to Identify Biomarkers Associated with Rapid eGFR Decline in Type 1 Diabetes.

BACKGROUND: Individuals with type 1 diabetes (T1D) demonstrate varied trajectories of estimated glomerular filtration rate (eGFR) decline. The molecular pathways underlying rapid eGFR decline in T1D are poorly understood, and individual-level risk of rapid eGFR decline is difficult to predict. METHODS: We designed a case-control study with multiple exposure measurements nested within 4 well-characterized T1D cohorts (FinnDiane, Steno, EDC, and CACTI) to identify biomarkers associated with rapid eGFR decline. Here, we report the rationale for and design of these studies as well as results of models testing associations of clinical characteristics with rapid eGFR decline in the study population, upon which "omics" studies will be built. Cases (n = 535) and controls (n = 895) were defined as having an annual eGFR decline of ≥3 and <1 mL/min/1.73 m2, respectively. Associations of demographic and clinical variables with rapid eGFR decline were tested using logistic regression, and prediction was evaluated using area under the curve (AUC) statistics. Targeted metabolomics, lipidomics, and proteomics are being performed using high-resolution mass-spectrometry techniques. RESULTS: At baseline, the mean age was 43 years, diabetes duration was 27 years, eGFR was 94 mL/min/1.73 m2, and 62% of participants were normoalbuminuric. Over 7.6-year median follow-up, the mean annual change in eGFR in cases and controls was -5.7 and 0.6 mL/min/1.73 m2, respectively. Younger age, longer diabetes duration, and higher baseline HbA1c, urine albumin-creatinine ratio, and eGFR were significantly associated with rapid eGFR decline. The cross-validated AUC for the predictive model incorporating these variables plus sex and mean arterial blood pressure was 0.74 (95% CI: 0.68-0.79; p < 0.001). CONCLUSION: Known risk factors provide moderate discrimination of rapid eGFR decline. Identification of blood and urine biomarkers associated with rapid eGFR decline in T1D using targeted omics strategies may provide insight into disease mechanisms and improve upon clinical predictive models using traditional risk factors.

Costs and outcomes of "intermediate" vs "minimal" care for youth-onset type 1 diabetes in six countries.

OBJECTIVE: Data are needed to demonstrate that providing an "intermediate" level of type 1 diabetes (T1D) care is cost-effective compared to "minimal" care in less-resourced countries. We studied these care scenarios in six countries. METHODS: We modeled the complications/costs/mortality/healthy life years (HLYs) associated with "intermediate" care including two blood glucose tests/day (mean HbA1c 9.0% [75 mmol/mol]) in three lower-gross domestic product (GDP) countries (Mali, Tanzania, Pakistan), or three tests/day (mean HbA1c 8.5% [69 mmol/mol]) in three higher-GDP countries (Bolivia, Sri Lanka, Azerbaijan); and compared findings to "minimal" care (mean HbA1c 12.5% [113 mmol/mol]). A discrete time Markov illness-death model with age and calendar-year-dependent transition probabilities was developed, with inputs of 30 years of complications and Standardized Mortality Rate data from the youth cohort in the Pittsburgh Epidemiology of Diabetes Complications Study, background mortality, and costs determined from international and local prices. RESULTS: Cumulative 30 years incidences of complications were much lower for "intermediate care" than "minimal care", for example, for renal failure incidence was 68.1% (HbA1c 12.5%) compared to 3.9% (9%) and 2.4% (8.5%). For Mali, Tanzania, Pakistan, Bolivia, Sri Lanka, and Azerbaijan, 30 years survival was 50.1%/52.7%/76.7%/72.5%/82.8%/89.2% for "intermediate" and 8.5%/10.1%/39.4%/25.8%/45.5%/62.1% for "minimal" care, respectively. The cost of a HLY gained as a % GDP/capita was 141.1%/110.0%/52.3%/41.8%/17.0%/15.6%, respectively. CONCLUSIONS: Marked reductions in complications rates and mortality are achievable with "intermediate" T1D care achieving mean clinic HbA1c of 8.5% to 9% (69-75 mmol/mol). This is also "very cost-effective" in four of six countries according to the WHO "Fair Choices" approach which costs HLYs gained against GDP/capita.

The role of coronary artery calcification testing in incident coronary artery disease risk prediction in type 1 diabetes.

AIMS/HYPOTHESIS: We sought to assess the role of coronary artery calcification (CAC) and its progression in predicting incident coronary artery disease (CAD) in individuals with type 1 diabetes using data from the Pittsburgh Epidemiology of Diabetes Complications (EDC) Study. METHODS: The present study examined 292 participants who had at least one CAC measure and were free from CAD at baseline; 181 (62%) had repeat CAC assessments 4-8 years later and did not develop CAD between the two CAC measures. The HRs of incident CAD events were estimated using Cox models in categorised or in appropriately transformed CAC scores. C statistics and net reclassification improvement (NRI) were used to assess the added predictive value of CAC for incident CAD. RESULTS: At baseline, the mean age of participants was 39.4 years and the mean diabetes duration was 29.5 years. There were 76 participants who experienced a first incident CAD event over an average follow-up of 10.7 years. At baseline, compared with those without CAC (Agatston score = 0), the adjusted HR (95% CI) in groups of 1-99, 100-399 and ≥400 was 3.1 (1.6, 6.1), 4.4 (2.0, 9.5) and 4.8 (1.9, 12.0), respectively. CAC density was inversely associated with incident CAD in those with CAC volume ≥100 (HR 0.3 [95% CI 0.1, 0.9]) after adjusting for volume score. Among participants with repeated CAC measures, annual CAC progression was positively associated with incident CAD after controlling for baseline CAC. The HR (95% CI) for above vs below the median annual CAC volume progression was 3.2 (1.2, 8.5). When compared with a model that only included established risk factors, the addition of CAC improved the predictive ability for incident CAD events in the whole group. CONCLUSIONS/INTERPRETATION: CAC is strongly associated with incident CAD events in individuals with type 1 diabetes; its inclusion in CAD risk models may lead to improvement in prediction over established risk factors.

Non-traditional biomarkers and incident diabetes in the Diabetes Prevention Program: comparative effects of lifestyle and metformin interventions.

AIMS/HYPOTHESIS: We compared the associations of circulating biomarkers of inflammation, endothelial and adipocyte dysfunction and coagulation with incident diabetes in the placebo, lifestyle and metformin intervention arms of the Diabetes Prevention Program, a randomised clinical trial, to determine whether reported associations in general populations are reproduced in individuals with impaired glucose tolerance, and whether these associations are independent of traditional diabetes risk factors. We further investigated whether biomarker-incident diabetes associations are influenced by interventions that alter pathophysiology, biomarker concentrations and rates of incident diabetes. METHODS: The Diabetes Prevention Program randomised 3234 individuals with impaired glucose tolerance into placebo, metformin (850 mg twice daily) and intensive lifestyle groups and showed that metformin and lifestyle reduced incident diabetes by 31% and 58%, respectively compared with placebo over an average follow-up period of 3.2 years. For this study, we measured adiponectin, leptin, tissue plasminogen activator (as a surrogate for plasminogen activator inhibitor 1), high-sensitivity C-reactive protein, IL-6, monocyte chemotactic protein 1, fibrinogen, E-selectin and intercellular adhesion molecule 1 at baseline and at 1 year by specific immunoassays. Traditional diabetes risk factors were defined as family history, HDL-cholesterol, triacylglycerol, BMI, fasting and 2 h glucose, HbA1c, systolic blood pressure, inverse of fasting insulin and insulinogenic index. Cox proportional hazard models were used to assess the effects of each biomarker on the development of diabetes assessed semi-annually and the effects of covariates on these. RESULTS: E-selectin, (HR 1.19 [95% CI 1.06, 1.34]), adiponectin (0.84 [0.71, 0.99]) and tissue plasminogen activator (1.13 [1.03, 1.24]) were associated with incident diabetes in the placebo group, independent of diabetes risk factors. Only the association between adiponectin and diabetes was maintained in the lifestyle (0.69 [0.52, 0.92]) and metformin groups (0.79 [0.66, 0.94]). E-selectin was not related to diabetes development in either lifestyle or metformin groups. A novel association appeared for change in IL-6 in the metformin group (1.09 [1.021, 1.173]) and for baseline leptin in the lifestyle groups (1.31 [1.06, 1.63]). CONCLUSIONS/INTERPRETATION: These findings clarify associations between an extensive group of biomarkers and incident diabetes in a multi-ethnic cohort with impaired glucose tolerance, the effects of diabetes risk factors on these, and demonstrate differential modification of associations by interventions. They strengthen evidence linking adiponectin to diabetes development, and argue against a central role for endothelial dysfunction. The findings have implications for the pathophysiology of diabetes development and its prevention.

Does diabetes prevention translate into reduced long-term vascular complications of diabetes?

The global epidemic of type 2 diabetes has prompted numerous studies and public health efforts to reduce its development. A variety of interventions, including lifestyle modifications and pharmacological agents directed at ameliorating the major risk factors for type 2 diabetes, are of proven efficacy in reducing the development of type 2 diabetes in people with impaired glucose tolerance. While prevention of the hyperglycaemia characteristic of diabetes is arguably an important, clinically relevant outcome, a more compelling outcome with greater clinical significance is the prevention or reduction of the relatively diabetes-specific microvascular and less-specific cardiovascular disease (CVD) complications associated with diabetes. These complications cause the majority of morbidity and excess mortality associated with diabetes. Any reduction in diabetes should, logically, also reduce the occurrence of its long-term complications; however, most diabetes prevention trials have not been of sufficient duration to allow such an evaluation. The limited long-term data, largely from the Da Qing Diabetes Prevention Study (DQDPS) and the Diabetes Prevention Program (DPP) and their respective follow-up studies (DQDPOS and DPPOS), suggest a reduction in microvascular complications and amelioration of CVD risk factors. Only the DQDPOS and Study to Prevent Non-Insulin-Dependent Diabetes Mellitus (STOP-NIDDM) studies have shown a reduction in CVD events and only DQDPOS has demonstrated a decrease in CVD and overall mortality. While these limited data are promising, whether diabetes prevention directly reduces complication-related morbidity and mortality remains unclear. Longer follow-up of prevention studies is needed to supplement the limited current clinical trial data, to help differentiate the effects of diabetes prevention itself from the means used to reduce diabetes development and to understand the balance among benefits, risks and costs of prevention.

Levels of type 1 diabetes care in children and adolescents for countries at varying resource levels.

Optimal care for children and adolescents with type 1 diabetes is well described in guidelines, such as those of the International Society for Pediatric and Adolescent Diabetes. High-income countries can usually provide this, but the cost of this care is generally prohibitive for lower-income countries. Indeed, in most of these countries, very little care is provided by government health systems, resulting in high mortality, and high complications rates in those who do survive. As lower-income countries work toward establishing guidelines-based care, it is helpful to describe the levels of care that are potentially affordable, cost-effective, and result in substantially improved clinical outcomes. We have developed a levels of care concept with three tiers: "minimal care," "intermediate care," and "comprehensive (guidelines-based) care." Each tier contains levels, which describe insulin and blood glucose monitoring regimens, requirements for hemoglobin A1c (HbA1c) testing, complications screening, diabetes education, and multidisciplinary care. The literature provides various examples at each tier, including from countries where the life for a child and the changing diabetes in children programs have assisted local diabetes centres to introduce intermediate care. Intra-clinic mean HbA1c levels range from 12.0% to 14.0% (108-130 mmol/mol) for the most basic level of minimal care, 8.0% to 9.5% (64-80 mmol/mol) for intermediate care, and 6.9% to 8.5% (52-69 mmol/mol) for comprehensive care. Countries with sufficient resources should provide comprehensive care, working to ensure that it is accessible by all in need, and that resulting HbA1c levels correspond with international recommendations. All other countries should provide Intermediate care, while working toward the provision of comprehensive care.

Meta-genome-wide association studies identify a locus on chromosome 1 and multiple variants in the MHC region for serum C-peptide in type 1 diabetes.

AIMS/HYPOTHESIS: The aim of this study was to identify genetic variants associated with beta cell function in type 1 diabetes, as measured by serum C-peptide levels, through meta-genome-wide association studies (meta-GWAS). METHODS: We performed a meta-GWAS to combine the results from five studies in type 1 diabetes with cross-sectionally measured stimulated, fasting or random C-peptide levels, including 3479 European participants. The p values across studies were combined, taking into account sample size and direction of effect. We also performed separate meta-GWAS for stimulated (n = 1303), fasting (n = 2019) and random (n = 1497) C-peptide levels. RESULTS: In the meta-GWAS for stimulated/fasting/random C-peptide levels, a SNP on chromosome 1, rs559047 (Chr1:238753916, T>A, minor allele frequency [MAF] 0.24-0.26), was associated with C-peptide (p = 4.13 × 10-8), meeting the genome-wide significance threshold (p < 5 × 10-8). In the same meta-GWAS, a locus in the MHC region (rs9260151) was close to the genome-wide significance threshold (Chr6:29911030, C>T, MAF 0.07-0.10, p = 8.43 × 10-8). In the stimulated C-peptide meta-GWAS, rs61211515 (Chr6:30100975, T/-, MAF 0.17-0.19) in the MHC region was associated with stimulated C-peptide (ß [SE] = - 0.39 [0.07], p = 9.72 × 10-8). rs61211515 was also associated with the rate of stimulated C-peptide decline over time in a subset of individuals (n = 258) with annual repeated measures for up to 6 years (p = 0.02). In the meta-GWAS of random C-peptide, another MHC region, SNP rs3135002 (Chr6:32668439, C>A, MAF 0.02-0.06), was associated with C-peptide (p = 3.49 × 10-8). Conditional analyses suggested that the three identified variants in the MHC region were independent of each other. rs9260151 and rs3135002 have been associated with type 1 diabetes, whereas rs559047 and rs61211515 have not been associated with a risk of developing type 1 diabetes. CONCLUSIONS/INTERPRETATION: We identified a locus on chromosome 1 and multiple variants in the MHC region, at least some of which were distinct from type 1 diabetes risk loci, that were associated with C-peptide, suggesting partly non-overlapping mechanisms for the development and progression of type 1 diabetes. These associations need to be validated in independent populations. Further investigations could provide insights into mechanisms of beta cell loss and opportunities to preserve beta cell function.

Effect of Long-Term Metformin and Lifestyle in the Diabetes Prevention Program and Its Outcome Study on Coronary Artery Calcium.

BACKGROUND: Despite the reduced incidence of coronary heart disease with intensive risk factor management, people with diabetes mellitus and prediabetes remain at increased coronary heart disease risk. Diabetes prevention interventions may be needed to reduce coronary heart disease risk. This approach was examined in the DPP (Diabetes Prevention Program) and the DPPOS (Diabetes Prevention Program Outcome Study), a long-term intervention study in 3234 subjects with prediabetes (mean±SD age, 64±10 years) that showed reduced diabetes risk with lifestyle and metformin compared with placebo over 3.2 years. METHODS: The DPPOS offered periodic group lifestyle sessions to all participants and continued metformin in the originally randomized metformin group. Subclinical atherosclerosis was assessed in 2029 participants with coronary artery calcium (CAC) measurements after an average of 14 years of follow-up. The CAC scores were analyzed continuously as CAC severity and categorically as CAC presence (CAC score >0) and reported separately in men and women. RESULTS: There were no CAC differences between lifestyle and placebo intervention groups in either sex. CAC severity and presence were significantly lower among men in the metformin versus the placebo group (age-adjusted mean CAC severity, 39.5 versus 66.9 Agatston units, P=0.04; CAC presence, 75% versus 84%, P=0.02), but no metformin effect was seen in women. In multivariate analysis, the metformin effect in men was not influenced by demographic, anthropometric, or metabolic factors; by the development of diabetes mellitus; or by use/nonuse of statin therapy. CONCLUSIONS: Metformin may protect against coronary atherosclerosis in prediabetes and early diabetes mellitus among men. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00038727.

Hemoglobin A1c Level and Cardiovascular Disease Incidence in Persons With Type 1 Diabetes: An Application of Joint Modeling of Longitudinal and Time-to-Event Data in the Pittsburgh Epidemiology of Diabetes Complications Study.

Type 1 diabetes (T1D) is associated with increased risk of cardiovascular disease (CVD), but hyperglycemia (measured by hemoglobin A1c (HbA1c) level), which characterizes T1D, has itself been an inconsistent predictor of CVD incidence. However, only baseline HbA1c or a summary measure (e.g., mean level over follow-up) is usually analyzed. Joint models allow simultaneous modeling of repeatedly measured longitudinal covariates, using random effects, and time-to-event data. We evaluated data from the Pittsburgh Epidemiology of Diabetes Complications Study, an ongoing prospective cohort study of childhood-onset T1D that has followed participants since 1986-1988 and has repeatedly found little association between baseline HbA1c or mean follow-up HbA1c and coronary artery disease incidence. Of 561 participants without CVD at baseline, 263 (46.9%) developed CVD over a period of 25 years (1986-2014). In joint models, each 1% unit increase in HbA1c trajectory was associated with a 1.26-fold increased risk of CVD (95% confidence interval: 1.07, 1.45), after adjustment for baseline levels of other CVD risk factors, and a 1.13-fold increased risk (95% confidence interval: 0.99, 1.32) after adjustment for updated mean levels of other CVD risk factors. These findings, which support the need for good glycemic control to prevent CVD in persons with T1D, underscore the importance of utilizing methods incorporating within-subject variation over time when analyzing and interpreting longitudinal cohort study data.

Prevalence of Diagnosed Diabetes in Adults by Diabetes Type - United States, 2016.

Currently 23 million U.S. adults have been diagnosed with diabetes (1). The two most common forms of diabetes are type 1 and type 2. Type 1 diabetes results from the autoimmune destruction of the pancreas's beta cells, which produce insulin. Persons with type 1 diabetes require insulin for survival; insulin may be given as a daily shot or continuously with an insulin pump (2). Type 2 diabetes is mainly caused by a combination of insulin resistance and relative insulin deficiency (3). A small proportion of diabetes cases might be types other than type 1 or type 2, such as maturity-onset diabetes of the young or latent autoimmune diabetes in adults (3). Although the majority of prevalent cases of type 1 and type 2 diabetes are in adults, national data on the prevalence of type 1 and type 2 in the U.S. adult population are sparse, in part because of the previous difficulty in classifying diabetes by type in surveys (2,4,5). In 2016, supplemental questions to help distinguish diabetes type were added to the National Health Interview Survey (NHIS) (6). This study used NHIS data from 2016 to estimate the prevalence of diagnosed diabetes among adults by primary type. Overall, based on self-reported type and current insulin use, 0.55% of U.S. adults had diagnosed type 1 diabetes, representing 1.3 million adults; 8.6% had diagnosed type 2 diabetes, representing 21.0 million adults. Of all diagnosed cases, 5.8% were type 1 diabetes, and 90.9% were type 2 diabetes; the remaining 3.3% of cases were other types of diabetes. Understanding the prevalence of diagnosed diabetes by type is important for monitoring trends, planning public health responses, assessing the burden of disease for education and management programs, and prioritizing national plans for future type-specific health services.

The relationship of blood glucose with cardiovascular disease is mediated over time by traditional risk factors in type 1 diabetes: the DCCT/EDIC study.

AIMS/HYPOTHESIS: Chronic hyperglycaemia, as measured by HbA1c levels, is a major risk factor for atherosclerosis and cardiovascular disease (CVD) in type 1 diabetes. Our aim was to describe the degree to which the effect of HbA1c on the risk of CVD is mediated by its effect on traditional risk factors over time, and how these mediation pathways change over time. METHODS: The DCCT and its observational follow-up study, the Epidemiology of Diabetes Interventions and Complications (EDIC), followed 1441 participants for a mean of 27 years, with periodic measurement of HbA1c and risk factors over time. We assessed the proportion of the HbA1c effect on risk of CVD that was mediated through its effects on systolic BP (SBP), pulse rate, triacylglycerols and LDL-cholesterol (LDLc) levels, and how the proportion mediated changed over time. RESULTS: The association of HbA1c with CVD outcomes was stable over time, while that of traditional risk factors (SBP, pulse rate, triacylglycerols and LDLc) increased. At 10 years of follow-up, the effect of HbA1c on 10 year CVD risk was minimally mediated by SBP (2.7%), increasing to 26% at 20 years. Likewise, from 10 year follow-up to 20 year follow-up, the proportion of HbA1c effect mediated through pulse rate increased from 6.3% to 29.3%, through triacylglycerols from 2.2% to 22.4%, and through LDLc from 9.2% to 30.7%. CONCLUSIONS/INTERPRETATION: As participants age, the predictive association of mean HbA1c on subsequent CVD events is increasingly mediated by its effect on standard risk factors. Thus, management of traditional non-glycaemic CVD risk factors may have increasing benefits in an ageing type 1 diabetes population with longstanding hyperglycaemia. TRIAL REGISTRATION: ClinicalTrials.gov NCT00360893 and NCT00360815.

Regional Gray Matter Volumes as Related to Psychomotor Slowing in Adults with Type 1 Diabetes.

OBJECTIVE: Psychomotor slowing is a common cognitive complication in type 1 diabetes (T1D), but its neuroanatomical correlates and risk factors are unclear. In nondiabetic adults, smaller gray matter volume (GMV) and presence of white matter hyperintensities are associated with psychomotor slowing. We hypothesize that smaller GMV in prefronto-parietal regions explains T1D-related psychomotor slowing. We also inspect the contribution of microvascular disease and hyperglycemia. METHODS: GMV, white matter hyperintensities (WMH), and glucose levels were measured concurrently with a test of psychomotor speed (Digit Symbol Substitution Test [DSST]) in 95 adults with childhood-onset T1D (mean age/duration = 49/41 years) and 135 similarly aged non-T1D adults. Linear regression models tested associations between DSST and regional GMV, controlling for T1D, sex, and education; a bootstrapping method tested whether regional GMV explained between-group differences in DSST. For the T1D cohort, voxel-based and a priori regions-of-interest methods further tested associations between GMV and DSST, adjusting for WMH, hyperglycemia, and age. RESULTS: Bilateral putamen, but no other regions examined, significantly attenuated DSST differences between the cohorts (bootstrapped unstandardized indirect effects: -3.49, -3.26; 95% confidence interval = -5.49 to -1.80, -5.29 to -1.44, left and right putamen, respectively). Among T1D, DSST was positively associated with GMV of bilateral putamen and left thalamus. Neither WMH, hyperglycemia, age, nor other factors substantially modified these relationships. CONCLUSIONS: For middle-aged adults with T1D and cerebral microvascular disease, GMV of basal ganglia may play a critical role in regulating psychomotor speed, as measured via DSST. Studies to quantify the impact of basal ganglia atrophy concurrent with WMH progression on psychomotor slowing are warranted.