Plasma Biomarkers of Brain Injury and Their Association With Brain MRI and Cognition in Type 1 Diabetes.

OBJECTIVE: To evaluate associations between plasma biomarkers of brain injury and MRI and cognitive measures in participants with type 1 diabetes (T1D) from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study. RESEARCH DESIGN AND METHODS: Plasma amyloid-ß-40, amyloid-ß-42, neurofilament light chain (NfL), phosphorylated Tau-181 (pTau-181), and glial fibrillary acidic protein (GFAP) were measured in 373 adults who participated in the DCCT/EDIC study. MRI assessments included total brain and white matter hyperintensity volumes, white matter mean fractional anisotropy, and indices of Alzheimer disease (AD)-like atrophy and predicted brain age. Cognitive measures included memory and psychomotor and mental efficiency tests and assessments of cognitive impairment. RESULTS: Participants were 60 (range 44-74) years old with 38 (30-51) years' T1D duration. Higher NfL was associated with an increase in predicted brain age (0.51 years per 20% increase in NfL; P < 0.001) and a 19.5% increase in the odds of impaired cognition (P < 0.01). Higher NfL and pTau-181 were associated with lower psychomotor and mental efficiency (P < 0.001) but not poorer memory. Amyloid-ß measures were not associated with study measures. A 1% increase in mean HbA1c was associated with a 14.6% higher NfL and 12.8% higher pTau-181 (P < 0.0001). CONCLUSIONS: In this aging T1D cohort, biomarkers of brain injury did not demonstrate an AD-like profile. NfL emerged as a biomarker of interest in T1D because of its association with higher HbA1c, accelerated brain aging on MRI, and cognitive dysfunction. Our study suggests that early neurodegeneration in adults with T1D is likely due to non-AD/nonamyloid mechanisms.

Intensive Glycemic Management Is Associated With Reduced Retinal Structure Abnormalities on Ocular Coherence Tomography in the DCCT/EDIC Study.

OBJECTIVE: To investigate quantitative and qualitative changes in retinal structure using optical coherence tomography (OCT) and their associations with systemic or other risk factors in individuals with type 1 diabetes (T1D). RESEARCH DESIGN AND METHODS: In the Epidemiology of Diabetes Interventions and Complications (EDIC) study, OCT images were obtained during study years 25-28 (2019-2022) in 937 participants; 54% and 46% were from the original intensive (INT) and conventional (CONV) glycemic management treatment groups, respectively. RESULTS: Average age for participants was 61 years old, diabetes duration 39 years, and HbA1c 7.6%. Participants originally in the CONV group were more likely to have disorganization of retinal inner layers (DRIL) (CONV 27.3% vs. INT 18.7%; P = 0.0003), intraretinal fluid (CONV 24.4% vs. INT 19.2%; P = 0.0222), and intraretinal cysts (CONV 20.8% vs. INT 16.6%; P = 0.0471). In multivariable models, sex, age, smoking, mean updated systolic blood pressure, and history of "clinically significant" macular edema (CSME) and of anti-VEGF treatment were independently associated with changes in central subfield thickness, while HbA1c, BMI, and history of CSME and of ocular surgery were associated with DRIL. Visual acuity (VA) decline was associated with significant thinning of all retinal subfields except for the central and inner nasal subfields. CONCLUSIONS: Early intensive glycemic management in T1D is associated with a decreased risk of DRIL. This important morphological abnormality was associated with a history of macular edema, a history of ocular surgery, and worse VA. This study reveals benefits of intensive glycemic management on the retina beyond features detected by fundus photographs and ophthalmoscopy.

Major adverse events in youth-onset type 1 and type 2 diabetes: The SEARCH and TODAY studies.

AIMS: To determine contemporary incidence rates and risk factors for major adverse events in youth-onset T1D and T2D. METHODS: Participant interviews were conducted once during in-person visits from 2018 to 2019 in SEARCH (T1D: N = 564; T2D: N = 149) and semi-annually from 2014 to 2020 in TODAY (T2D: N = 495). Outcomes were adjudicated using harmonized, predetermined, standardized criteria. RESULTS: Incidence rates (events per 10,000 person-years) among T1D participants were: 10.9 ophthalmologic; 0 kidney; 11.1 nerve, 3.1 cardiac; 3.1 peripheral vascular; 1.6 cerebrovascular; and 15.6 gastrointestinal events. Among T2D participants, rates were: 40.0 ophthalmologic; 6.2 kidney; 21.2 nerve; 21.2 cardiac; 10.0 peripheral vascular; 5.0 cerebrovascular and 42.8 gastrointestinal events. Despite similar mean diabetes duration, complications were higher in youth with T2D than T1D: 2.5-fold higher for microvascular, 4.0-fold higher for macrovascular, and 2.7-fold higher for gastrointestinal disease. Univariate logistic regression analyses in T1D associated age at diagnosis, female sex, HbA1c and mean arterial pressure (MAP) with microvascular events. In youth-onset T2D, composite microvascular events associated positively with MAP and negatively with BMI, however composite macrovascular events associated solely with MAP. CONCLUSIONS: In youth-onset diabetes, end-organ events were infrequent but did occur before 15 years diabetes duration. Rates were higher and had different risk factors in T2D versus T1D.

Neuropathic Pain With and Without Diabetic Peripheral Neuropathy in Type 1 Diabetes.

OBJECTIVE: Diabetic peripheral neuropathy (DPN) is common; however, the features and burden of neuropathic pain (NP) in type 1 diabetes (T1D) are poorly understood. We evaluated the incidence of first occurrence, annual prevalence, remission, and risk factors for NP during long-term follow-up of participants with T1D. RESEARCH DESIGN AND METHODS: The Michigan Neuropathy Screening Instrument (MNSI) was administered annually (1994-2020) for 1,324 participants in the Epidemiology of Diabetes Interventions and Complications (EDIC) study. NP with clinical signs of DPN (NP DPN+) was defined according to self-reported NP plus an examination score >2, while NP without clinical signs of DPN (NP DPN-) was defined according to self-reported NP and an examination score ≤2. RESULTS: At EDIC year 1, median age for participants was 36 years (interquartile range 30, 41), diabetes duration 13 years (10, 18), and HbA1c 7.9% (7.2, 8.9). At year 26 (median diabetes duration 39 years), cumulative incidence of NP was 57%, regardless of concomitant clinical signs of DPN (36% NP DPN+ vs. 46% NP DPN-). NP prevalence was 20% at 26 years (11% NP DPN+ and 9% NP DPN-), suggesting frequent remission. Annualized remission rates were similar regardless of pain medication use. In addition to HbA1c, female sex was associated with NP DPN-. CONCLUSIONS: NP incidence in T1D was high and frequently occurred in the absence of clinical signs of neuropathy, as assessed with the MNSI. Pain remission was not explained by pain medication use. Effective clinical strategies for identification and management are needed.

Diabetes Modulates Iodothyronine Deiodinase 2 Expression in the Mouse Retina: A Role for Thyroid Hormone in the Pathogenesis of Diabetic Retinopathy.

Purpose: Clinical investigations associate hypothyroidism with an increased risk for microvascular complications, yet the mechanism by which thyroid hormone regulates the development of diabetic retinopathy is not clearly understood. We investigated the role of iodothyronine deiodinase 2 (DIO2) in the pathogenesis of diabetic retinopathy. Methods: Retinas from streptozotocin-induced diabetic and nondiabetic mice were evaluated by RNA sequencing, RT-PCR, and immunostaining. Media and cell lysates from mouse retinal microvascular endothelial cells and retinal astrocytes exposed to physiologic (5 mM) and high glucose (25 mM) containing media were assessed by liquid chromatography-tandem mass spectrometry to measure tetraiodothyronine (T4) and tri-iodothyronine (T3) concentrations and by Western blot analysis to determine the relationship of T4/T3 to oxidative stress and inflammatory mediators. Cell death was determined by Trypan Blue exclusion assay. Results: At 12 weeks of diabetes duration, retinas from diabetic mice compared with nondiabetic mice demonstrated a significant decrease in Dio2 transcripts and Dio2 gene and protein (P < 0.05) expression. When cultured in the presence of high glucose, both mouse retinal astrocytes and microvascular endothelial cells demonstrated a significant reduction of DIO2 protein compared with cells cultured in physiologic glucose. High glucose inhibited generation of T3, leading to a significantly increased T4/T3 (P < 0.0079). Supplementation of cells with T3, but not T4, prevented the high glucose-induced rise in endothelial nitric oxide synthase, intercellular cell adhesion molecule 1, and endothelial cell death (P < 0.0079). Conclusions: Decreased intraretinal T3 owing to diabetes-induced loss of DIO2 may lead to dysfunction and death of cells in the retina, thereby contributing to the pathogenesis of early diabetic retinopathy.

Utility of the NIH Toolbox Cognition Battery in middle to older aged adults with longstanding type 1 diabetes: The DCCT/EDIC study.

Objective: Adults with type 1 diabetes (T1D) face an increased risk for cognitive decline and dementia. Diabetes-related and vascular risk factors have been linked to cognitive decline using detailed neuropsychological testing; however, it is unclear if cognitive screening batteries can detect cognitive changes associated with aging in T1D. Method: 1,049 participants with T1D (median age 59 years; range 43-74) from the Diabetes Control and Complications Trial (DCCT), and the follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study, completed the NIH Toolbox Cognition Battery (NIHTB-C) and Montreal Cognitive Assessment (MoCA). Neuropsychological assessments, depression, glycated hemoglobin levels (HbA1c), severe hypoglycemia, T1D complications, and vascular risk factors were assessed repeatedly over 32 years to determine associations with current NIHTB-C performance. Available cognitive data was clinically adjudicated to determine cognitive impairment status. Results: NIHTB-C scores had moderate associations (r = 0.36-0.53) with concurrently administered neuropsychological tests. In multivariate models, prior severe hypoglycemic episodes, depression symptoms, nephropathy, lower BMI, and higher HbA1c and LDL cholesterol were associated with poorer NIHTB-C Fluid Cognition Composite scores. The NIHTB-C adequately detected adjudicated cognitive impairment (Area Under the Curve = 0.86; optimal cut score ≤90). The MoCA performed similarly (Area Under the Curve = 0.83; optimal cut score ≤25). Conclusions: The NIHTB-C is sensitive to the cognitive effects of diabetes-related and vascular risk factors, correlated with neuropsychological testing, and accurately detects adjudicated cognitive impairment. These data support its use as a screening test in middle to older aged adults with T1D to determine if referral for detailed neuropsychological assessment is needed.

Patterns of Regional Brain Atrophy and Brain Aging in Middle- and Older-Aged Adults With Type 1 Diabetes.

Importance: Little is known about structural brain changes in type 1 diabetes (T1D) and whether there are early manifestations of a neurodegenerative condition like Alzheimer disease (AD) or evidence of premature brain aging. Objective: To evaluate neuroimaging markers of brain age and AD-like atrophy in participants with T1D in the Diabetes Control and Complications Trial (DCCT)/Epidemiology of Diabetes Interventions and Complications (EDIC) study, identify which brain regions are associated with the greatest changes in patients with T1D, and assess the association between cognition and brain aging indices. Design, Setting, and Participants: This cohort study leveraged data collected during the combined DCCT (randomized clinical trial, 1983-1993) and EDIC (observational study, 1994 to present) studies at 27 clinical centers in the US and Canada. A total of 416 eligible EDIC participants and 99 demographically similar adults without diabetes were enrolled in the magnetic resonance imaging (MRI) ancillary study, which reports cross-sectional data collected in 2018 to 2019 and relates it to factors measured longitudinally in DCCT/EDIC. Data analyses were performed between July 2020 and April 2022. Exposure: T1D diagnosis. Main Outcomes and Measures: Psychomotor and mental efficiency were evaluated using verbal fluency, digit symbol substitution test, trail making part B, and the grooved pegboard. Immediate memory scores were derived from the logical memory subtest of the Wechsler memory scale and the Wechsler digit symbol substitution test. MRI and machine learning indices were calculated to predict brain age and quantify AD-like atrophy. Results: This study included 416 EDIC participants with a median (range) age of 60 (44-74) years (87 of 416 [21%] were older than 65 years) and a median (range) diabetes duration of 37 (30-51) years. EDIC participants had consistently higher brain age values compared with controls without diabetes, indicative of approximately 6 additional years of brain aging (EDIC participants: ß, 6.16; SE, 0.71; control participants: ß, 1.04; SE, 0.04; P < .001). In contrast, AD regional atrophy was comparable between the 2 groups. Regions with atrophy in EDIC participants vs controls were observed mainly in the bilateral thalamus and putamen. Greater brain age was associated with lower psychomotor and mental efficiency among EDIC participants (ß, -0.04; SE, 0.01; P < .001), but not among controls. Conclusions and Relevance: The findings of this study suggest an increase in brain aging among individuals with T1D without any early signs of AD-related neurodegeneration. These increases were associated with reduced cognitive performance, but overall, the abnormal patterns seen in this sample were modest, even after a mean of 38 years with T1D.

Relationships Between the Cumulative Incidences of Long-term Complications in Type 1 Diabetes: The DCCT/EDIC Study.

OBJECTIVE: To describe the relationships between the cumulative incidences of long-term complications in individuals with type 1 diabetes (T1D) and assess whether observed associations are independent of age, duration of diabetes, and glycemic levels. METHODS: Proliferative diabetic retinopathy (PDR), clinically significant macular edema (CSME), reduced estimated glomerular filtration rate (eGFR), amputations, cardiovascular disease (CVD), and mortality were assessed in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study over ∼30 years. RESEARCH DESIGN AND RESULTS: The cumulative incidence of complications ranged from 3% (amputations) to 37% (CSME). There were large differences in the cumulative incidence of PDR between participants with versus without prior CSME (66% vs. 15%), reduced eGFR (59% vs. 29%), and amputation (68% vs. 32%); reduced eGFR with or without prior PDR (25% vs. 9%), amputation (48% vs. 13%), and CVD (30% vs. 11%); CVD with or without prior reduced eGFR (37% vs. 14%) and amputation (50% vs. 16%); and mortality with or without prior reduced eGFR (22% vs. 9%), amputation (35% vs. 8%), and CVD (25% vs. 8%). Adjusted for age, duration of T1D, and mean updated HbA1c, the complications and associations with higher risk included PDR with CSME (hazard ratio [HR] 1.88; 95% CI 1.42, 2.50), reduced eGFR (HR 1.41; 95% CI 1.01, 1.97), and CVD (HR 1.43; 95% CI 1.06, 1.92); CSME with higher risk of PDR (HR 3.94; 95% CI 3.18 4.89), reduced eGFR (HR 1.49; 95% CI 1.10, 2.01), and CVD (HR 1.35; 95% CI 1.03, 1.78); reduced eGFR with higher risk of CVD (HR 2.09; 95% CI 1.44, 3.03), and death (HR 3.40; 95% CI 2.35, 4.92); amputation(s) with death (HR 2.97; 95% CI 1.70, 2.90); and CVD with reduced eGFR (HR 1.59; 95% CI 1.08, 2.34) and death (HR 1.95; 95% CI 1.32, 2.90). CONCLUSIONS: Long-term micro- and macrovascular complications and mortality are highly correlated. Age, diabetes duration, and glycemic levels do not completely explain these associations.

Cardiometabolic Risk Factors and Incident Cardiovascular Disease Events in Women vs Men With Type 1 Diabetes.

Importance: The lower risk of cardiovascular disease (CVD) among women compared with men in the general population may be diminished among those with diabetes. Objective: To evaluate cardiometabolic risk factors and their management in association with CVD events in women vs men with type 1 diabetes enrolled in the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study. Design, Setting, and Participants: This cohort study used data obtained during the combined DCCT (randomized clinical trial, conducted 1983-1993) and EDIC (observational study, conducted 1994 to present) studies through April 30, 2018 (mean [SD] follow-up, 28.8 [5.8] years), at 27 clinical centers in the US and Canada. Data analyses were performed between July 2021 and April 2022. Exposure: During the DCCT phase, patients were randomized to intensive vs conventional diabetes therapy. Main Outcomes and Measures: Cardiometabolic risk factors and CVD events were assessed via detailed medical history and focused physical examinations. Blood and urine samples were assayed centrally. CVD events were adjudicated by a review committee. Linear mixed models and Cox proportional hazards models evaluated sex differences in cardiometabolic risk factors and CVD risk over follow-up. Results: A total of 1441 participants with type 1 diabetes (mean [SD] age at DCCT baseline, 26.8 [7.1] years; 761 [52.8%] men; 1390 [96.5%] non-Hispanic White) were included. Over the duration of the study, compared with men, women had significantly lower body mass index (BMI, calculated as weight in kilograms divided by height in meters squared; ß = -0.43 [SE, 0.16]; P = .006), waist circumference (ß = -10.56 cm [SE, 0.52 cm]; P < .001), blood pressure (systolic: ß = -5.77 mm Hg [SE, 0.35 mm Hg]; P < .001; diastolic: ß = -3.23 mm Hg [SE, 0.26 mm Hg]; P < .001), and triglyceride levels (ß = -10.10 mg/dL [SE, 1.98 mg/dL]; P < .001); higher HDL cholesterol levels (ß = 9.36 mg/dL [SE, 0.57 mg/dL]; P < .001); and similar LDL cholesterol levels (ß = -0.76 mg/dL [SE, 1.22 mg/dL]; P = .53). Women, compared with men, achieved recommended targets more frequently for blood pressure (ie, <130/80 mm Hg: 90.0% vs 77.4%; P < .001) and triglycerides (ie, <150 mg/dL: 97.3% vs 90.5%; P < .001). However, sex-specific HDL cholesterol targets (ie, ≥50 mg/dL for women, ≥40 mg/dL for men) were achieved less often (74.3% vs 86.6%; P < .001) and cardioprotective medications were used less frequently in women than men (ie, angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker: 29.6% [95% CI, 25.7%-33.9%] vs 40.0% [95% CI, 36.1%-44.0%]; P = .001; lipid-lowering medication: 25.3% [95% CI, 22.1%-28.7%] vs 39.6% [95% CI, 36.1%-43.2%]; P < .001). Women also had significantly higher pulse rates (mean [SD], 75.2 [6.8] beats per minute vs 71.8 [6.9] beats per minute; P < .001) and hemoglobin A1c levels (mean [SD], 8.3% [1.0%] vs 8.1% [1.0%]; P = .01) and achieved targets for tighter glycemic control less often than men (ie, hemoglobin A1c <7%: 11.2% [95% CI, 9.3%-13.3%] vs 14.0% [95% CI, 12.0%-16.3%]; P = .03). Conclusions and Relevance: These findings suggest that despite a more favorable cardiometabolic risk factor profile, women with type 1 diabetes did not have a significantly lower CVD event burden than men, suggesting a greater clinical impact of cardiometabolic risk factors in women vs men with diabetes. These findings call for conscientious optimization of the control of CVD risk factors in women with type 1 diabetes.

Brain Structure Among Middle-aged and Older Adults With Long-standing Type 1 Diabetes in the DCCT/EDIC Study.

OBJECTIVE: Individuals with type 1 diabetes mellitus (T1DM) are living to ages when neuropathological changes are increasingly evident. We hypothesized that middle-aged and older adults with long-standing T1DM will show abnormal brain structure in comparison with control subjects without diabetes. RESEARCH DESIGN AND METHODS: MRI was used to compare brain structure among 416 T1DM participants in the Epidemiology of Diabetes Interventions and Complications (EDIC) study with that of 99 demographically similar control subjects without diabetes at 26 U.S. and Canadian sites. Assessments included total brain (TBV) (primary outcome), gray matter (GMV), white matter (WMV), ventricle, and white matter hyperintensity (WMH) volumes and total white matter mean fractional anisotropy (FA). Biomedical assessments included HbA1c and lipid levels, blood pressure, and cognitive assessments of memory and psychomotor and mental efficiency (PME). Among EDIC participants, HbA1c, severe hypoglycemia history, and vascular complications were measured longitudinally. RESULTS: Mean age of EDIC participants and control subjects was 60 years. T1DM participants showed significantly smaller TBV (least squares mean ± SE 1,206 ± 1.7 vs. 1,229 ± 3.5 cm3, P < 0.0001), GMV, and WMV and greater ventricle and WMH volumes but no differences in total white matter mean FA versus control subjects. Structural MRI measures in T1DM were equivalent to those of control subjects who were 4-9 years older. Lower PME scores were associated with altered brain structure on all MRI measures in T1DM participants. CONCLUSIONS: Middle-aged and older adults with T1DM showed brain volume loss and increased vascular injury in comparison with control subjects without diabetes, equivalent to 4-9 years of brain aging.

Continuous Glucose Monitoring in Adults With Type 1 Diabetes With 35 Years Duration From the DCCT/EDIC Study.

OBJECTIVE: We evaluated blinded continuous glucose monitoring (CGM) profiles in a subset of adults with type 1 diabetes from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study to characterize the frequency of glycemic excursions and contributing factors. RESEARCH DESIGN AND METHODS: CGM-derived metrics were compared for daytime and nighttime periods using blinded CGM for a minimum of 6.5 days (average 11.9 days) and correlated with HbA1c levels, routine use of diabetes devices, and other characteristics in 765 participants. RESULTS: Participants were 58.9 ± 6.5 years of age with diabetes duration 36.8 ± 4.9 years and HbA1c 7.8 ± 1.2%; 58% used insulin pumps, and 27% used personal, unblinded CGM. Compared with daytime, nighttime mean sensor glucose was lower, percent time in range 70-180 mg/dL (TIR) was similar, and hypoglycemia was more common. Over the entire recording period, only 9% of the 765 participants achieved >70% TIR and only 28% achieved <1% of observations of <54 mg/dL. Indeed, participants with the highest percentage of hypoglycemia had the lowest HbA1c levels. However, use of insulin pumps and CGM decreased the percent time at <54 mg/dL. CONCLUSIONS: In adults with long-standing type 1 diabetes, short-term blinded CGM profiles revealed frequent clinically significant hypoglycemia (<54 mg/dL) during the night and more time in hyperglycemia during the day. The small subset of participants using routine CGM and insulin pumps had fewer hypoglycemic and hyperglycemic excursions and lower HbA1c levels. Thus, strategies to lower meal-stimulated hyperglycemia during the day and prevent hypoglycemia at night are relevant clinical goals in older patients with type 1 diabetes.

Pediatric Diabetic Retinopathy: Updates in Prevalence, Risk Factors, Screening, and Management.

PURPOSE OF REVIEW: Diabetic retinopathy (DR) is a microvascular complication of diabetes mellitus and a major cause of vision loss worldwide. The purpose of this review is to provide an update on the prevalence of diabetic retinopathy in youth, discuss risk factors, and review recent advances in diabetic retinopathy screening. RECENT FINDINGS: While DR has long been considered a microvascular complication, recent data suggests that retinal neurodegeneration may precede the vascular changes associated with DR. The prevalence of DR has decreased in type 1 diabetes (T1D) patients following the results of the Diabetes Control and Complications Trial and implementation of intensive insulin therapy, with prevalence ranging from 14-20% before the year 2000 to 3.7-6% after 2000. In contrast, the prevalence of diabetic retinopathy in pediatric type 2 diabetes (T2D) is higher, ranging from 9.1-50%. Risk factors for diabetic retinopathy are well established and include glycemic control, diabetes duration, hypertension, and hyperlipidemia, whereas diabetes technology use including insulin pumps and continuous glucose monitors has been shown to have protective effects. Screening for DR is recommended for youth with T1D once they are aged ≥ 11 years or puberty has started and diabetes duration of 3-5 years. Pediatric T2D patients are advised to undergo screening at or soon after diagnosis, and annually thereafter, due to the insidious nature of T2D. Recent advances in DR screening methods including point of care and artificial intelligence technology have increased access to DR screening, while being cost-saving to patients and cost-effective to healthcare systems. While the prevalence of diabetic retinopathy in youth with T1D has been declining over the last few decades, there has been a significant increase in the prevalence of DR in youth with T2D. Improving access to diabetic retinopathy screening using novel screening methods may help improve detection and early treatment of diabetic retinopathy.

Cognitive performance declines in older adults with type 1 diabetes: results from 32 years of follow-up in the DCCT and EDIC Study.

BACKGROUND: With improved treatment, individuals with type 1 diabetes are living longer but there is limited information on the effects of type 1 diabetes on cognitive ability as they become older adults. We followed up individuals with type 1 diabetes to identify independent risk factors for cognitive decline as people age. METHODS: 1051 participants with type 1 diabetes enrolled in the Diabetes Control and Complications Trial (DCCT) and its follow-up Epidemiology of Diabetes Interventions and Complications (EDIC) study. Participants completed cognitive assessments at baseline (median age 27 years) and 2, 5, 18, and 32 years later (median age 59). HbA1c levels, frequency of severe hypoglycaemia, non-glycemic risk factors such as elevated blood pressure, and microvascular and macrovascular complications were assessed repeatedly. We examined the effects of these on measures of memory and psychomotor and mental efficiency. These studies are registered with clinicaltrials.gov, NCT00360815 (DCCT) and NCT00360893 (EDIC). FINDINGS: Over 32 years of follow-up, we found substantive declines in memory and psychomotor and mental efficiency. Between 18 and 32 years of follow-up, the decline in psychomotor and mental efficiency was five times larger than the change from baseline to year 18. Independent of the other risk factors and comorbidities, exposure to higher HbA1c levels, more episodes of severe hypoglycaemia, and elevated systolic blood pressure were associated with greater decrements in psychomotor and mental efficiency that was most notable by year 32 (p<0·0001). The combined effect of the presence of these three risk factors is the equivalent to an additional 9·4 years of age. INTERPRETATION: Cognitive function declines with ageing in type 1 diabetes. The association of glycaemia and blood pressure levels with cognitive decline suggests that better management might preserve cognitive function. FUNDING: United States National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Disease.

Residual ß cell function in long-term type 1 diabetes associates with reduced incidence of hypoglycemia.

BACKGROUNDWe investigated residual ß cell function in Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study participants with an average 35-year duration of type 1 diabetes mellitus (T1DM).METHODSSerum C-peptide was measured during a 4-hour mixed-meal tolerance test. Associations with metabolic outcomes and complications were explored among nonresponders (all C-peptide values after meal <0.003 nmol/L) and 3 categories of responders, classified by peak C-peptide concentration (nmol/L) as high (>0.2), intermediate (>0.03 to ≤0.2), and low (≥ 0.003 to ≤0.03).RESULTSOf the 944 participants, 117 (12.4%) were classified as responders. Residual C-peptide concentrations were associated with higher DCCT baseline concentrations of stimulated C-peptide (P value for trend = 0.0001). Residual C-peptide secretion was not associated with current or mean HbA1c, HLA high-risk haplotypes for T1DM, or the current presence of T1DM autoantibodies. The proportion of subjects with a history of severe hypoglycemia was lower with high (27%) and intermediate (48%) residual C-peptide concentrations than with low (74%) and no (70%) residual C-peptide concentrations (P value for trend = 0.0001). Responders and nonresponders demonstrated similar rates of advanced microvascular complications.CONCLUSIONß Cell function can persist in long-duration T1DM. With a peak C-peptide concentration of >0.03 nmol/L, we observed clinically meaningful reductions in the prevalence of severe hypoglycemia.TRIAL REGISTRATIONClinicalTrials.gov NCT00360815 and NCT00360893.FUNDINGDivision of Diabetes Endocrinology and Metabolic Diseases of the National Institute of Diabetes and Digestive and Kidney Diseases (DP3-DK104438, U01 DK094176, and U01 DK094157).

Risk Factors for Longitudinal Resting Heart Rate and Its Associations With Cardiovascular Outcomes in the DCCT/EDIC Study.

OBJECTIVE: Individuals with diabetes have higher resting heart rate compared with those without, which may be predictive of long-term cardiovascular disease (CVD) risk. Using data from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study, we evaluated whether the beneficial effect of intensive versus conventional diabetes therapy on heart rate persisted, the factors mediating the differences in heart rate between treatment groups, and the effects of heart rate on future CVD risk. RESEARCH DESIGN AND METHODS: Longitudinal changes in heart rate, from annual electrocardiograms over 22 years of EDIC follow-up, were evaluated in 1,402 participants with type 1 diabetes. Linear mixed models were used to assess the effect of DCCT treatment group on mean heart rate over time, and Cox proportional hazards models were used to estimate the effect of heart rate on CVD risk during DCCT/EDIC. RESULTS: At DCCT closeout, 52% of participants were male and mean ± SD age was 33 ± 7 years, diabetes duration 12 ± 5 years, and HbA1c 7.4 ± 1.2% (intensive) and 9.1 ± 1.6% (conventional). Through EDIC, participants in the intensive group had significantly lower heart rate in comparison with the conventional group. While significant group differences in heart rate were fully attenuated by DCCT/EDIC mean HbA1c, higher heart rate predicted CVD and major adverse cardiovascular events independent of other risk factors. CONCLUSIONS: After 22 years of follow-up, former intensive versus conventional therapy remained significantly associated with lower heart rate, consistent with the long-term beneficial effects of intensive therapy on CVD. DCCT treatment group effects on heart rate were explained by differences in DCCT/EDIC mean HbA1c.

The First Genome-Wide Association Study for Type 2 Diabetes in Youth: The Progress in Diabetes Genetics in Youth (ProDiGY) Consortium.

The prevalence of type 2 diabetes in youth has increased substantially, yet the genetic underpinnings remain largely unexplored. To identify genetic variants predisposing to youth-onset type 2 diabetes, we formed ProDiGY, a multiethnic collaboration of three studies (TODAY, SEARCH, and T2D-GENES) with 3,006 youth case subjects with type 2 diabetes (mean age 15.1 ± 2.9 years) and 6,061 diabetes-free adult control subjects (mean age 54.2 ± 12.4 years). After stratifying by principal component-clustered ethnicity, we performed association analyses on ∼10 million imputed variants using a generalized linear mixed model incorporating a genetic relationship matrix to account for population structure and adjusting for sex. We identified seven genome-wide significant loci, including the novel locus rs10992863 in PHF2 (P = 3.2 × 10-8; odds ratio [OR] = 1.23). Known loci identified in our analysis include rs7903146 in TCF7L2 (P = 8.0 × 10-20; OR 1.58), rs72982988 near MC4R (P = 4.4 × 10-14; OR 1.53), rs200893788 in CDC123 (P = 1.1 × 10-12; OR 1.32), rs2237892 in KCNQ1 (P = 4.8 × 10-11; OR 1.59), rs937589119 in IGF2BP2 (P = 3.1 × 10-9; OR 1.34), and rs113748381 in SLC16A11 (P = 4.1 × 10-8; OR 1.04). Secondary analysis with 856 diabetes-free youth control subjects uncovered an additional locus in CPEB2 (P = 3.2 × 10-8; OR 2.1) and consistent direction of effect for diabetes risk. In conclusion, we identified both known and novel loci in the first genome-wide association study of youth-onset type 2 diabetes.

Circulating adhesion molecules and associations with HbA1c, hypertension, nephropathy, and retinopathy in the Treatment Options for type 2 Diabetes in Adolescent and Youth study.

BACKGROUND: The Treatment Options for type 2 Diabetes in Adolescent and Youth study, a randomized clinical trial of three treatments for type 2 diabetes (T2DM) in youth, demonstrated treatment failure (defined as sustained HbA1c ≥8%, or inability to wean insulin after 3 months after acute metabolic decomposition) in over half of the participants. Given that binding of mononuclear cells to vascular endothelium, initiated by cellular adhesion molecules and chemokines, is an early step in vascular injury, we sought to evaluate (a) changes in cellular adhesion molecule levels during the trial; (b) effect of diabetes treatment; and (c) association of markers with HbA1c, hypertension, hypercholesterolemia, nephropathy, and retinopathy. METHODS: Participants (n = 515 of 699) that had baseline assessment of adhesion molecules (monocyte chemoattractant protein-1 [MCP-1], vascular cell adhesion marker [VCAM], intercellular adhesion marker [ICAM], and E-Selectin) and at least one other assessment, measured at month 12, 24, or 36, were included. RESULTS: Over 1 to 3 years, significant increases in MCP-1 and decreases in VCAM (both P < .0001) concentrations were found; however, no significant interactions were identified with treatment group for any molecule. For every 1% increase in HbA1c, ICAM increased by 1.8%, VCAM by 1.5%, and E-selectin by 6.8% (all P < .0001). E-selectin increased by 3.7% and 4.2% for every 10 mm Hg increase in systolic and diastolic blood pressure, respectively (both P < .0001). ICAM was 10.2% higher and E-selectin was 15.5% higher in participants with microalbuminuria (both P < .01). There was no significant association of adhesion molecule levels with retinopathy. CONCLUSION: Concentrations of cellular adhesion molecules rise with increasing HbA1c in youth with T2DM, and are associated with blood pressure and microalbuminuria, markers of vascular injury.