Cognitive function in type 1 diabetic adults with early exposure to severe hypoglycemia: a 16-year follow-up study

Alpha cell receptor for advanced glycation end products associate with glucagon expression in type 1 diabetes

Hypoglycemia in type 1 diabetes associates with changes in the pancreatic islet α cells, where the receptor for advanced glycation end products (RAGE) is highly expressed. This study compared islet RAGE expression in donors without diabetes, those at risk of, and those with type 1 diabetes. Laser-dissected islets were subject to RNA bioinformatics and adjacent pancreatic tissue were assessed by confocal microscopy. We found that islets from type 1 diabetes donors had differential expression of the RAGE gene (AGER) and its correlated genes, based on glucagon expression. Random forest machine learning revealed that AGER was the most important predictor for islet glucagon levels. Conversely, a generalized linear model identified that glucagon expression could be predicted by expression of RAGE signaling molecules, its ligands and enzymes that create or clear RAGE ligands. Confocal imaging co-localized RAGE, its ligands and signaling molecules to the α cells. Half of the type 1 diabetes cohort comprised of adolescents and a patient with history of hypoglycemia-all showed an inverse relationship between glucagon and RAGE. These data confirm an association between glucagon and islet RAGE, its ligands and signaling pathways in type 1 diabetes, which warrants functional investigation into a role for RAGE in hypoglycemia.

Comparison Between Continuous Versus Flash Glucose Monitoring in Children, Adolescents, and Young Adults with Type 1 Diabetes: An 8-Week Prospective Randomized Trial

INTRODUCTION

To assess the impact of real-time continuous glucose monitoring (RT-CGM) instead of first-generation flash glucose monitoring (FGM) on hypoglycaemia in children and adolescents with type 1 diabetes.

METHODS

In this randomized controlled interventional study, young individuals with type 1 diabetes used RT-CGM or FGM for 8 weeks. We evaluated changes in time below range (TBR), severe hypoglycaemia (SH), HbA1c, glycaemic variability, and impaired awareness of hypoglycaemia with RT-CGM (intervention group) in comparison with FGM.

RESULTS

We randomly assigned 37 participants to either the intervention group (n = 19) or the control group (n = 18). At 8 weeks, we did not find a decrease in TBR in either group, but there was a significant reduction in SH in the intervention group. For participants with TBR ≥ 5% at baseline, we observed significant reductions in 24-h TBR, wake TBR, sleep TBR, and glucose variability at 8 weeks in the intervention group.

CONCLUSIONS

The use of RT-CGM versus FGM decreased SH in young individuals with type 1 diabetes, and TBR and glucose variability in patients with a higher TBR at baseline. The patient's history should be taken into account when advising on the method of blood glucose monitoring, as RT-CGM could be more effective in younger patients at high risk for SH.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04249102.

Multi-Timepoint Metabolic Fingerprinting of a Post-Episode Period of Hypoglycemia and Ketoacidosis Among Children With Type 1 Diabetes

Background: Acute complications of type 1 diabetes mellitus such as diabetes ketoacidosis (DKA) and hypoglycemia (HG) are detrimental in a short- and long-term perspective. Restoration of normoglycemia and correction of pH do not mean that all metabolic disturbances caused by HG or DKA are immediately reversed.

Aim: This study aimed to identify serum metabolic changes caused by an episode of DKA and HG that may indicate the mechanisms contributing to long-term consequences of DKA/HG.

Materials and methods: Four groups of children with type 1 diabetes were recruited. The first two study groups included patients after an episode of DKA or HG, respectively. Additionally, two comparative groups were recruited—children with established type 1 diabetes (EDM) and patients with newly diagnosed diabetes without diabetes ketoacidosis (NDM). Serum samples were collected in three group-specific time points (since the hospital admission): HG 0h-12h–48h; DKA or NDM 0h-24h–72 h; and one random fasting sample from patients with EDM. Two batches of 100 samples each were created: for DKA batch 20 × 3 DKA patients, 10 × 3 NDM and 10 EDM; for HG batch: 10 × 3 HG patients, 25 EDM and 15 × 3 NDM. All patients within the batches were age and sex matched. Metabolic fingerprinting was performed with LC-QTOF-MS.

Results: Four metabolites were associated with a DKA episode occurring in the preceding 72 h: three were found higher after the DKA episode versus comparative groups: lysophosphatidylcholine (LPC) (18:1), sphingomyelins (SM) (34:0 and d18:0/15:0), and one was found lower: LPC (18:0). Similarly, four metabolites were identified for the HG episode in the last 48 h: three were found higher after the HG episode versus comparative groups: two lysophosphatidylethanolamines (LPE) (18:2 and 20:3) and one LPC (18:2); and one was found lower after the HG episode: oxy-phosphatidylocholine (PC O-34:4).

Conclusions: We found eight metabolites whose levels may be traced in the serum, indicating the DKA or HG episode for up to 72 h and 48 h, respectively. Acute complications of diabetes may cause persistent metabolic disturbances long after pH and glucose level normalization.

Comparison of cognitive function in older adults with type 1 diabetes, type 2 diabetes, and no diabetes: results from the Study of Longevity in Diabetes (SOLID)

INTRODUCTION

The incidence of both type 1 diabetes (T1D) and type 2 diabetes (T2D) is increasing. Life expectancy is improving in T1D, resulting in a growing population of elderly adults with diabetes. While it is well established that older adults with T2D are at increased risk of cognitive impairment, little is known regarding cognitive aging in T1D and how their cognitive profiles may differ from T2D.

RESEARCH DESIGN AND METHODS

We compared baseline cognitive function and low cognitive function by diabetes status (n=734 T1D, n=232 T2D, n=247 without diabetes) among individuals from the Study of Longevity in Diabetes (mean age=68). We used factor analysis to group cognition into five domains and a composite measure of total cognition. Using linear and logistic regression models, we examined the associations between diabetes type and cognitive function, adjusting for demographics, comorbidities, depression, and sleep quality.

RESULTS

T1D was associated with lower scores on total cognition, language, executive function/psychomotor processing speed, and verbal episodic memory, and greater odds of low executive function/psychomotor processing speed (OR=2.99, 95% CI 1.66 to 5.37) and verbal episodic memory (OR=1.92, 95% CI 1.07 to 3.46), compared with those without diabetes. T2D was associated with lower scores on visual episodic memory. Compared with T2D, T1D was associated with lower scores on verbal episodic memory and executive function/psychomotor processing speed and greater odds of low executive function/psychomotor processing speed (OR=1.74, 95% CI 1.03 to 2.92).

CONCLUSIONS

Older adults with T1D had significantly poorer cognition compared with those with T2D and those without diabetes even after accounting for a range of comorbidities. Future studies should delineate how to reduce risk in this vulnerable population who are newly surviving to old age.

Impact of glucose metabolism on the developing brain

Glucose is the most important substrate for proper brain functioning and development, with an increased glucose consumption in relation to the need of creating new brain structures and connections. Therefore, alterations in glucose homeostasis will inevitably be associated with changes in the development of the Nervous System. Several studies demonstrated how the alteration of glucose homeostasis - both hyper and hypoglycemia- may interfere with the development of brain structures and cognitivity, including deficits in intelligence quotient, anomalies in learning and memory, as well as differences in the executive functions. Importantly, differences in brain structure and functionality were found after a single episode of diabetic ketoacidosis suggesting the importance of glycemic control and stressing the need of screening programs for type 1 diabetes to protect children from this dramatic condition. The exciting progresses of the neuroimaging techniques such as diffusion tensor imaging, has helped to improve the understanding of the effects, outcomes and mechanisms underlying brain changes following dysglycemia, and will lead to more insights on the physio-pathological mechanisms and related neurological consequences about hyper and hypoglycemia.

The Aging Vasculature: Glucose Tolerance, Hypoglycemia and the Role of the Serum Response Factor

The fastest growing demographic in the U.S. at the present time is those aged 65 years and older. Accompanying advancing age are a myriad of physiological changes in which reserve capacity is diminished and homeostatic control attenuates. One facet of homeostatic control lost with advancing age is glucose tolerance. Nowhere is this more accentuated than in the high proportion of older Americans who are diabetic. Coupled with advancing age, diabetes predisposes affected subjects to the onset and progression of cardiovascular disease (CVD). In the treatment of type 2 diabetes, hypoglycemic episodes are a frequent clinical manifestation, which often result in more severe pathological outcomes compared to those observed in cases of insulin resistance, including premature appearance of biomarkers of senescence. Unfortunately, molecular mechanisms of hypoglycemia remain unclear and the subject of much debate. In this review, the molecular basis of the aging vasculature (endothelium) and how glycemic flux drives the appearance of cardiovascular lesions and injury are discussed. Further, we review the potential role of the serum response factor (SRF) in driving glycemic flux-related cellular signaling through its association with various proteins.

Detection of Hypoglycemia Using Measures of EEG Complexity in Type 1 Diabetes Patients

Previous literature has demonstrated that hypoglycemic events in patients with type 1 diabetes (T1D) are associated with measurable scalp electroencephalography (EEG) changes in power spectral density. In the present study, we used a dataset of 19-channel scalp EEG recordings in 34 patients with T1D who underwent a hyperinsulinemic-hypoglycemic clamp study. We found that hypoglycemic events are also characterized by EEG complexity changes that are quantifiable at the single-channel level through empirical conditional and permutation entropy and fractal dimension indices, i.e., the Higuchi index, residuals, and tortuosity. Moreover, we demonstrated that the EEG complexity indices computed in parallel in more than one channel can be used as the input for a neural network aimed at identifying hypoglycemia and euglycemia. The accuracy was about 90%, suggesting that nonlinear indices applied to EEG signals might be useful in revealing hypoglycemic events from EEG recordings in patients with T1D.

A systematic review of the effect of prior hypoglycaemia on cognitive function in type 1 diabetes

BACKGROUND

The effect of prior hypoglycaemia on cognitive function in type 1 diabetes is an important unresolved clinical question. In this systematic review, we aimed to summarize the studies exploring the impact of prior hypoglycaemia on any aspect of cognitive function in type 1 diabetes.

METHODS

We used a multidatabase search platform Healthcare Database Advanced Search to search Medline, PubMed, EMBASE, EMCARE, CINAHL, PsycINFO, BNI, HMIC, and AMED from inception until 1 May 2019. We included studies on type 1 diabetes of any age. The outcome measure was any aspect of cognitive function.

RESULTS

The 62 studies identified were grouped as severe hypoglycaemia (SH) in childhood (⩽18 years) and adult-onset (>18 years) diabetes, nonsevere hypoglycaemia (NSH) and nocturnal hypoglycaemia (NH). SH in early childhood-onset diabetes, especially seizures and coma, was associated with poorer memory (verbal and visuospatial), as well as verbal intelligence. Among adult-onset diabetes, SH was associated with poorer cognitive performance in the older age (>55 years) group only. Early versus late exposure to SH had a significant association with cognitive dysfunction (CD). NSH and NH did not have any significant association with CD, while impaired awareness of hypoglycaemia was associated with poorer memory and cognitive-processing speeds.

CONCLUSION

The effect of SH on cognitive function is age dependent. Exposure to SH in early childhood (<10 years) and older age groups (>55 years) was associated with a moderate effect on the decrease in cognitive function in type 1 diabetes [PROSPERO ID: CRD42019141321].

Cognitive dysfunctions in individuals with diabetes mellitus

Some patients with type 1 and type 2 diabetes mellitus (DM) present with cognitive dysfunctions. The pathophysiology underlying this complication is not well understood. Type 1 DM has been associated with a decrease in the speed of information processing, psychomotor efficiency, attention, mental flexibility, and visual perception. Longitudinal epidemiological studies of type 1 DM have indicated that chronic hyperglycemia and microvascular disease, rather than repeated severe hypoglycemia, are associated with the pathogenesis of DM-related cognitive dysfunction. However, severe hypoglycemic episodes may contribute to cognitive dysfunction in high-risk patients with DM. Type 2 DM has been associated with memory deficits, decreased psychomotor speed, and reduced frontal lobe/executive function. In type 2 DM, chronic hyperglycemia, long duration of DM, presence of vascular risk factors (e.g., hypertension and obesity), and microvascular and macrovascular complications are associated with the increased risk of developing cognitive dysfunction. The pathophysiology of cognitive dysfunction in individuals with DM include the following: (1) role of hyperglycemia, (2) role of vascular disease, (3) role of hypoglycemia, and (4) role of insulin resistance and amyloid. Recently, some investigators have proposed that type 3 DM is correlated to sporadic Alzheimer's disease. The molecular and biochemical consequences of insulin and insulin-like growth factor resistance in the brain compromise neuronal survival, energy production, gene expression, plasticity, and white matter integrity. If patients claim that their performance is worsening or if they ask about the effects of DM on functioning, screening and assessment are recommended.

The effect of type 1 diabetes on the developing brain

The effect of type 1 diabetes on the developing brain is a topic of primary research interest. A variety of potential dysglycaemic insults to the brain can cause cellular and structural injury and lead to altered neuropsychological outcomes. These outcomes might be subtle in terms of cognition but appear to persist into adult life. Age and circumstance at diagnosis appear to play a substantial role in potential CNS injury. A history of diabetic ketoacidosis and chronic hyperglycaemia appear to be more injurious than previously suspected, whereas a history of severe hypoglycaemia is perhaps less injurious. Neurocognitive deficits manifest across multiple cognitive domains, including executive function and speed of information processing. Some evidence suggests that subtle brain injury might directly contribute to psychological and mental health outcomes. Impaired executive function and mental health, in turn, could affect patients' adherence and the ability to make adaptive lifestyle choices. Impaired executive functioning creates a potential feedback loop of diabetic dysglycaemia leading to brain injury, further impaired executive function and mental health, which results in suboptimal adherence, and further dysglycaemia. Clinicians dealing with patients with suboptimal glycaemic outcomes should be aware of these potential issues.

Hypoglycaemia Remains the Key Obstacle to Optimal Glycaemic Control - Continuous Glucose Monitoring is the Solution

We queried PubMed and other internet databases to identify studies, meta-analyses, review articles and other data sources regarding hypoglycaemia incidence/costs/impacts and continuous glucose monitoring (CGM) use. Our analysis of the evidence showed that hypoglycaemia remains a significant health concern and a primary obstacle to optimal adherence to prescribed diabetes treatment. In addition to its adverse clinical consequences, hypoglycaemia negatively impacts quality of life and places additional financial burdens on patients, patient families, employers and healthcare payers. Clinical trials have shown that the use of CGM can reduce the incidence and duration of hypoglycaemic episodes. This article reviews relevant CGM studies, discusses the prevalence and clinical/financial implications of hypoglycaemia, and explores the strengths and limitations of current CGM systems in minimising the burden of hypoglycaemia.

A longitudinal investigation of cognitive function in children and adolescents with type 1 diabetes mellitus

OBJECTIVE

Cross-sectional studies find altered cognition in youth with type 1 diabetes mellitus (T1DM). However, few longitudinal studies have examined the trajectories of their cognitive performance over time. The aims of this study were to explore longitudinal change in cognitive function in youth with T1DM as compared with nondiabetic sibling controls, and how glycemic control and age of onset influence cognitive performance over time.

METHODS

We assessed crystallized intelligence, visual-spatial ability, delayed memory, and processing speed at 3 time points using the same cognitive tasks in youth with T1DM and sibling controls. Hierarchical linear modeling examined relationships between diabetes, hyperglycemia (HbA1c values), age of onset, and cognition over 5.5 y.

RESULTS

Youth with diabetes performed worse than controls on visual-spatial ability and memory tasks over time, and did not improve as much in processing speed. Greater hyperglycemia was associated with lower crystallized intelligence and slower processing speed but better memory across all time points. There was a stronger negative relationship between hyperglycemia and visual-spatial ability for youth with earlier compared with later onset diabetes. Importantly, within-person decreases in hyperglycemia between time points were associated with improved visual-spatial ability and faster processing speed.

CONCLUSIONS

On average, differences in cognitive function between youth with T1DM and nondiabetic relatives are maintained or increase during childhood and adolescence. Hyperglycemia and age of onset can have negative effects on the developmental trajectories of cognitive processes in youth with T1DM. However, treatments that lower hyperglycemia may lead to improved cognitive function in youth with T1DM.

Effect of verbal task complexity in a working memory paradigm in patients with type 1 diabetes. A fMRI study

Type 1 diabetes (T1D) is commonly diagnosed in childhood and adolescence, and the developing brain has to cope with its deleterious effects. Although brain adaptation to the disease may not result in evident cognitive dysfunction, the effects of T1D on neurodevelopment could alter the pattern of BOLD fMRI activation. The aim of this study was to explore the neural BOLD activation pattern in patients with T1D versus that of healthy matched controls while performing two visuospatial working memory tasks, which included a pair of assignments administered through a block design. In the first task (condition A), the subjects were shown a trial sequence of 3 or 4 white squares positioned pseudorandomly around a fixation point on a black background. After a fixed delay, a second corresponding sequence of 3 or 4 red squares was shown that either resembled (direct, 50%) or differed from (50%) the previous stimulation order. The subjects were required to press one button if the two spatial sequences were identical or a second button if they were not. In condition B, the participants had to determine whether the second sequence of red squares appeared in inverse order (inverse, 50%) or not (50%) and respond by pressing a button. If the latter sequence followed an order distinct from the inverse sequence, the subjects were instructed to press a different button. Sixteen patients with normal IQ and without diabetes complications and 16 healthy control subjects participated in the study. In the behavioral analysis, there were no significant differences between the groups in the pure visuo-spatial task, but the patients with diabetes exhibited poorer performance in the task with verbal stimuli (p < .001). However, fMRI analyses revealed that the patients with T1D showed significantly increased activation in the prefrontal inferior cortex, subcortical regions and the cerebellum (in general p < .001). These different activation patterns could be due to adaptive compensation mechanisms that are devoted to improving efficiency while solving more complex cognitive tasks.

Pioglitazone improves the ability of learning and memory via activating ERK1/2 signaling pathway in the hippocampus of T2DM rats

OBJECTIVE

To explore the correlation between effect of PIO (pioglitazone, PIO) on learning as well as memory and ERK1/2 (extracellular signal regulated kinase 1/2, ERK1/2) pathway in T2DM (type 2 diabetes mellitus, T2DM) rats, further to elucidate the potential mechanism of PIO in improvement of learning and memory.

METHODS

12-week-old male SD rats (number of 10 per group) were randomly divided into control group (CON), T2DM group (DM) and T2DM +PIO group (DM+PG). Rats in DM and DM+PG groups were given high fat diet for 20 weeks, then treated with Streptozotocin (27mg/kg) by intraperitoneal injection at 21week. After 72h, the FBG (fasting blood glucose, FBG) was greater than 7.0mmol/L can considered T2DM rats. DM+PG group was treated with PIO (10 mg·kg^-1·d^-1) by gavage daily. After Hyperinsulinemic-Euglycemic Clamp Study and Morris water maze test at 30-week, all of animals were sacrificed. The expressions of RKIP (Raf-1 kinase inhibitor protein, RKIP) and ERK1/2 in hippocampus were detected using Western Blot and real-time PCR.

RESULTS

The FBG level: DM group (7.68±0.54mmol/L) was higher than CON group (5.35±0.63mmol/L) and DM+PG group (6.07±0.84mmol/L), the differences were considered statistically significant (P <0.05). Hyperinsulinemic-Euglycemic Clamp Studies: GIR (glucose infusion rate, GIR) of DM group (21.02±5.10 mg·kg^-1·d^-1) was less than CON group (27.64±3.87 mg·kg^-1·d^-1) and DM+PG group (26.04 ±5.41 mg·kg^-1·d^-1), the differences were considered statistically significant (P <0.05). Morris water maze training: The escape latencies and searching platform performance of DM group (24.54±5.02s) decreased significantly compared with CON group (16.73±4.02s) and DM+PG group (18.05±4.12s) (P <0.05). Changes of RKIP, ERK, p-ERK protein relative content in rat hippocampus: Compared with CON groupand DM+PG group, the relative content of RKIP in DM group remarkably increased (P<0.01); ERK protein levels were not considered statistically significant among the three groups (P>0.05); The relative content of p-ERK1/2 protein in CON group and DM+PG group rats dorsal were higher than those in group DM, the difference was considered statistically significant (P<0.01). Changes in hippocampus of rat RKIP and ERK gene relative content: Compared with CON group and DM+PG group, levels of RKIP mRNA in DM group were significantly increased (P<0.01); ERK mRNA levels were not considered statistically significant among the three groups (P>0.05).

CONCLUSION

Activation of ERK1/2 signal transduction pathway via reducing RKIP in the hippocampus may be one of the mechanisms of PIO to improve the learning and memory of the T2DM rats.

Correlation Among Hypoglycemia, Glycemic Variability, and C-Peptide Preservation After Alefacept Therapy in Patients with Type 1 Diabetes Mellitus: Analysis of Data from the Immune Tolerance Network T1DAL Trial

PURPOSE

In natural history studies, maintenance of higher levels of C-peptide secretion (a measure of endogenous insulin production) correlates with a lower incidence of major hypoglycemic events in patients with type 1 diabetes mellitus (T1D), but it is unclear whether this is also true for drug-induced C-peptide preservation.

METHODS

We analyzed hypoglycemic events and glycemic control data from the T1DAL (Inducing Remission in New-Onset T1D with Alefacept) study, a trial of alefacept in new-onset T1D, which found significant C-peptide preservation at 1 and 2 years. We performed a post hoc analysis using mixed models of the association between the meal-stimulated 4-hour C-peptide AUC (4-hour AUC) and rates of major hypoglycemia, measures of glycemic control (glycosylated hemoglobin [HbA1c]; mean glucometer readings), and variability (glucometer SDs; highest and lowest readings), and an index of partial remission (insulin dose-adjusted HbA1c[ IDAA1c]).

FINDINGS

Data from 49 participants (33 in the alefacept group and 16 in the placebo group) were analyzed at baseline and 12 and 24 months. We found that the 4-hour AUC at baseline and at 1 year was a significant predictor of the number of hypoglycemic events during the ensuing 12-month interval (p = 0.030). There was a strong association between the 4-hour AUC and glucometer SDs (P < 0.001), highest readings (p < 0.001), and lowest readings (p = 0.03), all measures of glycemic variability. There was a strong inverse correlation between the 4-hour AUC and 2 measures of glycemic control: HbA1c and mean glucometer readings (both p < 0.001). There was also a strong inverse correlation between the 4-hour AUC and IDAA1c values (p < 0.001), as well as a strong correlation between IDAA1c values and glucometer SDs (p < 0.001), suggesting that reduced glycemic variability is associated with a trend toward partial remission. None of these analyses found a significant difference between the alefacept and placebo groups.

IMPLICATIONS

Measures of glycemic variability and control, including rates of hypoglycemia, are significantly correlated with preservation of C-peptide regardless of whether this is achieved by immune intervention with alefacept or natural variability in patients with new-onset T1D. Thus, preservation of endogenous insulin production by an immunomodulatory drug may confer clinical benefits similar to those seen in patients with higher C-peptide secretion due to slow disease progression.

The Impact of Diabetes on Brain Function in Childhood and Adolescence

A constant supply of glucose to the brain is critical for normal cerebral metabolism. The dysglycemia of type 1 diabetes (T1D) can affect activity, survival, and function of neural cells. Clinical studies in T1D have shown impairments in brain morphology and function. The most neurotoxic milieu seems to be young age and/or diabetic ketoacidosis at onset, severe hypoglycemia under the age of 6 years followed by chronic hyperglycemia. Adverse cognitive outcomes seem to be associated with poorer mental health outcomes. It is imperative to improve outcomes by investigating the mechanisms of injury so that neuroprotective strategies independent of glycemia can be identified.

Accuracy of blood glucose meters for self-monitoring affects glucose control and hypoglycemia rate in children and adolescents with type 1 diabetes

AIMS/HYPOTHESIS

This study investigated the accuracy of blood glucose meters for self-monitoring and its influence on glycated hemoglobin (HbA1c) levels and the frequency of hypoglycemic coma.

MATERIALS AND METHODS

Self-measured and simultaneously obtained laboratory blood glucose values from 9,163 patients with type 1 diabetes <18 years of age in the German/Austrian Diabetes Prospective Documentation Initiative registry were analyzed by investigating their compliance with the International Organization for Standardization (ISO) criteria (versions 2003 and 2013) and by error grid analyses. Regression models elucidated effects on glucose control and hypoglycemia rates.

RESULTS

Depending on the respective subgroup (defined by sex, age, duration of diabetes, mode of insulin therapy), 78.7-94.7% of the self-monitoring of blood glucose (SMBG) values met the old and 79.7-88.6% met the new ISO criteria. In Clarke and Parkes error grid analyses, the percentages of SMBG values in Zone A ranged between 92.8% and 94.6% (Clarke) and between 92.2% and 95.0% (Parkes). The patient group with SMBG devices measuring "far too low" (compared with the laboratory-obtained glucose levels) presented with a higher HbA1c level than those measuring "far too high," "too high," "identical/almost identical," or "too low" (based on quintiles of deviation). Performing "far too high" was associated with the highest rate of hypoglycemic coma in comparison with the other deviation quintiles.

CONCLUSIONS

This study showed that current SMBG devices fulfilled neither the previous nor the new ISO criteria. Large deviations of the SMBG values from the "true" glucose levels resulted in higher HbA1c levels and markedly increased rates of hypoglycemic events.

Managing type 1 diabetes in school: Recommendations for policy and practice

Diabetes requiring insulin is increasingly common and likely to impact students in most, if not all, schools. Diabetes and its complications have major personal, social and economic impact, and improved diabetes control reduces the risk of both short- and long-term complications. Evidence shows that more intensive management of diabetes - through frequent blood glucose monitoring, insulin administration with injections and/or insulin pumps, and careful attention to diet and exercise - leads to better control. Since children spend 30 to 35 hours per week at school, effectively managing their diabetes while there is integral to their short- and long-term health. The Canadian Paediatric Society and the Canadian Pediatric Endocrine Group recommend that minimum standards for supervision and care be established across Canada to support children and youth with type 1 diabetes in schools. These recommendations are derived from evidence-based clinical practice guidelines, with input from diabetes care providers from across Canada, and are consistent with the Canadian Diabetes Association's Guidelines for the Care of Students Living with Diabetes at School.

Risk factors for decline in IQ in youth with type 1 diabetes over the 12 years from diagnosis/illness onset

OBJECTIVE

This study examined illness-related change in intelligence quotient (IQ) in a cohort of youth with type 1 diabetes studied prospectively from disease onset in childhood to follow-up 12 years later in late adolescence/early adulthood.

RESEARCH DESIGN AND METHODS

Participants included type 1 diabetes patients (n = 95; mean age at follow-up 21.3 years) and healthy control participants (HCs; n = 67; mean age at follow-up 21.0 years) from a cohort followed prospectively. Measures included Wechsler Preschool and Primary Scale of Intelligence-Revised, Wechsler Intelligence Scale for Children-Revised, and Wechsler Abbreviated Scale of Intelligence and prospective collection of data on metabolic control history.

RESULTS

Young people with type 1 diabetes showed greater decline in verbal IQ (VIQ) and full-scale IQ (FSIQ), but not performance IQ (PIQ), than HCs. Within the diabetes group, a younger age at diabetes onset was associated with a decline in PIQ and FSIQ (P ≤ 0.001). A history of hypoglycemic seizures was associated with a decline in VIQ (P = 0.002). Long-term metabolic control was not associated with changes in IQ. Interaction terms were not significant, suggesting no moderating effect of one diabetes-related variable over another.

CONCLUSIONS

The presence of diabetes may negatively influence some aspects of IQ over time. Specific illness risk factors, such as an earlier age of disease onset and a history of hypoglycemic seizures, appear to put the young person at greater risk. Academic progress of children identified as at risk should be monitored and educational supports provided if necessary.

Hypoglycaemia in diabetes mellitus: epidemiology and clinical implications

Hypoglycaemia is a frequent adverse effect of treatment of diabetes mellitus with insulin and sulphonylureas. Fear of hypoglycaemia alters self-management of diabetes mellitus and prevents optimal glycaemic control. Mild (self-treated) and severe (requiring help) hypoglycaemia episodes are more common in type 1 diabetes mellitus but people with insulin-treated type 2 diabetes mellitus are also exposed to frequent hypoglycaemic events, many of which occur during sleep. Hypoglycaemia can disrupt many everyday activities such as driving, work performance and leisure pursuits. In addition to accidents and physical injury, the morbidity of hypoglycaemia involves the cardiovascular and central nervous systems. Whereas coma and seizures are well-recognized neurological sequelae of hypoglycaemia, much interest is currently focused on the potential for hypoglycaemia to cause dangerous and life-threatening cardiac complications, such as arrhythmias and myocardial ischaemia, and whether recurrent severe hypoglycaemia can cause permanent cognitive impairment or promote cognitive decline and accelerate the onset of dementia in middle-aged and elderly people with diabetes mellitus. Prevention of hypoglycaemia is an important part of diabetes mellitus management and strategies include patient education, glucose monitoring, appropriate adjustment of diet and medications in relation to everyday circumstances including physical exercise, and the application of new technologies such as real-time continuous glucose monitoring, modified insulin pumps and the artificial pancreas.

Neurocognitive outcomes in pediatric diabetes: a developmental perspective

The impact of diabetes on the developing brain is well-accepted. Effects on neurocognitive functioning are moderate but have larger functional implications, especially when considered through a developmental lens. Pathophysiological factors such as severe hypoglycemia and chronic hyperglycemia can alter developmental trajectories in early childhood and perhaps at later periods. In this paper, we selectively review neurocognitive outcomes in pediatric diabetes (largely type 1), integrating recent research from developmental neuroscience and neuroimaging. We examine the effects of diabetes at different stages and place findings within a neurodevelopmental diathesis/stress framework. Early-onset diabetes is associated with specific effects on memory and more global cognitive late-effects, but less is known about cognitive outcomes of diabetes in later childhood and in adolescence, a time of increased neurobehavioral vulnerability that has received relatively limited empirical attention. Studies are also needed to better elucidate risk and protective factors that may moderate neurodevelopmental outcomes in youth with diabetes.

Hypoglycemia

Hypoglycemia is a common, potentially avoidable consequence of diabetes treatment and is a major barrier to initiating or intensifying antihyperglycemic therapy in efforts to achieve better glycemic control. Therapy regimen and a history of hypoglycemia are the most important predictors of future events. Other risk factors include renal insufficiency, older age, and history of hypoglycemia-associated autonomic failure. Reported rates of hypoglycemia vary considerably among studies because of differences in study design, definitions used, and population included, among other factors. Although occurring more frequently in type 1 diabetes, hypoglycemia also is clinically important in type 2 diabetes. Symptoms experienced by patients vary among individuals, and many events remain undiagnosed. The incidence of severe events is unevenly distributed, with only a small proportion (∼ 5%) of individuals accounting for >50% of events. Consequently, clinicians must be conscientious in obtaining thorough patient histories, because an accurate picture of the frequency and severity of hypoglycemic events is essential for optimal diabetes management. Severe hypoglycemia in particular is associated with an increased risk of mortality, impairments in cognitive function, and adverse effects on patients' quality of life. Economically, hypoglycemia burdens the healthcare system and adversely affects workplace productivity, particularly after a nocturnal event. Ongoing healthcare reform efforts will result in even more emphasis on reducing this side effect of diabetes treatment. Therefore, improving patients' self-management skills and selecting or modifying therapy to reduce the risk of hypoglycemia will increase in importance for clinicians and patients alike.

Hypoglycemia induced by insulin as a triggering factor of cognitive deficit in diabetic children

This paper provides an overview of insulin-induced hypoglycemia as a triggering factor of cognitive deficit in children with type 1 diabetes mellitus. For this purpose, databases from 1961 to 2013 were used with the objective of detecting the primary publications that address the impact of hypoglycemia on cognitive performance of diabetic children. The results obtained from experimental animals were excluded. The majority of studies demonstrated that the cognitive deficit in diabetic children involves multiple factors including duration, intensity, severity, and frequency of hypoglycemia episodes. Additionally, age at the onset of type 1 diabetes also influences the cognitive performance, considering that early inception of the disease is a predisposing factor for severe hypoglycemia. Furthermore, the results suggest that there is a strong correlation between brain damage caused by hypoglycemia and cognitive deterioration. Therefore, a more cautious follow-up and education are needed to impede and treat hypoglycemia in children with diabetes mellitus.

Detection and treatment efficacy of hypoglycemic events in the everyday life of children younger than 7 yr

BACKGROUND

Mild hypoglycemia is commonly observed in children treated for type 1 diabetes mellitus (T1DM). Hypoglycemia disturbs cognition and learning.

OBJECTIVE

To describe how and to what extent hypoglycemia in young children with T1DM is detected in everyday life. To learn how parents and caregivers treat hypoglycemia and to evaluate how efficient this treatment is.

METHODS

Twenty-three children [12 girls, mean age: 4.5 yr, mean HbA1c: 59 mmol/mol (7.5%)], 17 of whom were treated with an insulin pump, underwent blinded continuous glucose monitoring (CGM). Data on symptoms and treatment of hypoglycemia were collected in a logbook. Plasma glucose values were collected through self-monitoring of blood glucose and entered in the logbook, and glucometer memories were uploaded. Data were collected during 1 wk in autumn and 1 wk in spring.

RESULTS

Only 32% of all hypoglycemic events were detected despite plasma glucose being checked 10 times per day. Most hypoglycemic events were asymptomatic (90% overall and 98% of those occurring at night). Untreated hypoglycemic events were associated with a relapse into hypoglycemia within 3 h in the majority of events. Compared to treatment of hypoglycemia events with a defined dose of simple carbohydrates, treatment with a mixed meal resulted in a significantly higher glucose value 1 and 2 h after the hypoglycemia.

CONCLUSION

For optimum treatment, children younger than 7 yr with T1DM need better strategies and support for detecting hypoglycemia with real-time CGM. Hypoglycemia should be treated with a defined dose of carbohydrates rather than a mixed meal.

Diabetes cognitive impairments and the effect of traditional chinese herbs

The problem of cognitive impairment resulting from diabetes is gaining more acceptance and attention. Both type 1 and type 2 diabetes mellitus have been proved to be associated with reduced performance on numerous domains of cognitive function. Although the exact mechanisms of cognitive impairments in diabetes have not been completely understood, hyperglycemia and insulin resistance seem to play significant roles. And other possible risk factors such as hypoglycemia, insulin deficiency, vascular risk factors, hyperactive HPA axis, depression, and altered neurotransmitters will also be examined. In the meanwhile, this review analyzed the role of the active ingredient of Chinese herbal medicine in the treatment of diabetes cognitive impairments.

Alzheimer disease and cognitive impairment associated with diabetes mellitus type 2: associations and a hypothesis

INTRODUCTION

Epidemiological studies have demonstrated that patients with diabetes mellitus have an increased risk of developing Alzheimer disease, but the relationship between the 2 entities is not clear.

DEVELOPMENT

Both diseases exhibit similar metabolic abnormalities: disordered glucose metabolism, abnormal insulin receptor signalling and insulin resistance, oxidative stress, and structural abnormalities in proteins and β-amyloid deposits. Different hypotheses have emerged from experimental work in the last two decades. One of the most comprehensive relates the microvascular damage in diabetic polyneuritis with the central nervous system changes occurring in Alzheimer disease. Another hypothesis considers that cognitive impairment in both diabetes and Alzheimer disease is linked to a state of systemic oxidative stress. Recently, attenuation of cognitive impairment and normalisation of values in biochemical markers for oxidative stress were found in patients with Alzheimer disease and concomitant diabetes. Antidiabetic drugs may have a beneficial effect on glycolysis and its end products, and on other metabolic alterations.

CONCLUSIONS

Diabetic patients are at increased risk for developing Alzheimer disease, but paradoxically, their biochemical alterations and cognitive impairment are less pronounced than in groups of dementia patients without diabetes. A deeper understanding of interactions between the pathogenic processes of both entities may lead to new therapeutic strategies that would slow or halt the progression of impairment.

Hypoglycemia: The neglected complication

Hypoglycemia is an important complication of glucose-lowering therapy in patients with diabetes mellitus. Attempts made at intensive glycemic control invariably increases the risk of hypoglycemia. A six-fold increase in deaths due to diabetes has been attributed to patients experiencing severe hypoglycemia in comparison to those not experiencing severe hypoglycemia Repeated episodes of hypoglycemia can lead to impairment of the counter-regulatory system with the potential for development of hypoglycemia unawareness. The short- and long-term complications of diabetes related hypoglycemia include precipitation of acute cerebrovascular disease, myocardial infarction, neurocognitive dysfunction, retinal cell death and loss of vision in addition to health-related quality of life issues pertaining to sleep, driving, employment, recreational activities involving exercise and travel. There is an urgent need to examine the clinical spectrum and burden of hypoglycemia so that adequate control measures can be implemented against this neglected life-threatening complication. Early recognition of hypoglycemia risk factors, self-monitoring of blood glucose, selection of appropriate treatment regimens with minimal or no risk of hypoglycemia and appropriate educational programs for healthcare professionals and patients with diabetes are the major ways forward to maintain good glycemic control, minimize the risk of hypoglycemia and thereby prevent long-term complications.

Recurrent hypoglycemia: boosting the brain's metabolic flexibility

For people with diabetes, recurrent episodes of hypoglycemia limit the brain's ability to sense dangerously low blood sugar levels. In this issue of the JCI, the mechanisms behind this clinical problem of hypoglycemia unawareness are addressed by Herzog et al. The authors provide compelling evidence that recurrent hypoglycemia enhances transport of lactate into the brain and, although not itself a major alternative fuel source, lactate may preserve neuronal function during hypoglycemia by maintaining neuronal glucose metabolism. These findings redefine our understanding of the brain's metabolic adaptations that result from recurrent hypoglycemia.

Defective counterregulation and hypoglycemia unawareness in diabetes: mechanisms and emerging treatments

For people with diabetes, hypoglycemia remains the limiting factor in achieving glycemic control. This article reviews recent advances in how the brain senses and responds to hypoglycemia. Novel mechanisms by which individuals with insulin-treated diabetes develop hypoglycemia unawareness and impaired counterregulatory responses are outlined. Prevention strategies for reducing the incidence of hypoglycemia are discussed.

The importance of hypoglycemia in diabetic patients

Hypoglycemia is one of the most important complications of diabetes treatment. The risk of severe hypoglycemia is higher in elderly patients, those having comorbidities such as vascular disease or renal failure, pregnant women and in children with type 1diabetes. Moreover, in type 2 diabetes, progressive insulin deficiency, longer duration of diabetes, and tight glycemic control increase the risk of hypoglycemia as much as type 1 diabetes.Episodes hypoglycemia may lead to impairment of counter-regulatory system, with the potential of development of hypoglycemia unawareness. So, hypoglycemia may increase the vascular events even death in addition to other possible detrimental effects. Glycemic control should be individualized based on patient characteristics with some degree of safety. Recognition of hypoglycemia risk factors, blood glucose monitoring, selection of appropriate regimens and educational programs for healthcare professionals and patients with diabetes are the major issues to maintain good glycemic control, minimize the risk of hypoglycemia, and prevent long- term complications.

Cognitive impairment in diabetic patients: Can diabetic control prevent cognitive decline?

It is well recognized that the prevalence of dementia is higher in diabetic patients than non‐diabetic subjects. The incidence of diabetes has been increasing because of dramatic changes in lifestyles, and combined with longer lifespans as a result of advances in medical technology, this has brought about an increase in the number of elderly diabetic patients. Together, aging and diabetes have contributed to dementia becoming a serious problem. Progression to dementia reduces quality of life, and imposes a burden on both patients themselves and the families supporting them. Therefore, preventing the complication of dementia will become more and more important in the future. Although many mechanisms have been considered for an association between diabetes and cognitive dysfunction, glucose metabolism abnormalities such as hyperglycemia and hypoglycemia, and insulin action abnormalities such as insulin deficiency and insulin resistance can be causes of cognitive impairment. Recent large‐scale longitudinal studies have found an association between glycemic control and cognitive decline, although it is still unclear how cognitive decline might be prevented by good glycemic control. However, at an early stage, it is necessary to detect moderate cognitive dysfunction and try to reduce the risk factors for it, which should result in prevention of dementia, as well as vascular events. In the present review, in addition to outlining an association between diabetes and cognitive function, we discuss how glycemic control and cognitive decline are related.

Diabetes and cognitive dysfunction

Cognitive dysfunction in type 1 and type 2 diabetes share many similarities, but important differences do exist. A primary distinguishing feature of type 2 diabetes is that people with this disorder often (but not invariably) do poorly on measures of learning and memory, whereas deficits in these domains are rarely seen in people with type 1 diabetes. Chronic hyperglycaemia and microvascular disease contribute to cognitive dysfunction in both type 1 and type 2 diabetes, and both disorders are associated with mental and motor slowing and decrements of similar magnitude on measures of attention and executive functioning. Additionally, both types are characterised by neural slowing, increased cortical atrophy, microstructural abnormalities in white matter tracts, and similar, but not identical, changes in concentrations of brain neurometabolites. Disconcertingly, the rapid rise in obesity and type 2 diabetes in all age groups might result in a substantial increase in prevalence of diabetes-related cognitive dysfunction.

Academic skills in children with early-onset type 1 diabetes: the effects of diabetes-related risk factors

AIM

The study aimed to assess the effects of diabetes-related risk factors, especially severe hypoglycaemia,on the academic skills of children with early-onset type 1 diabetes mellitus (T1DM).

METHOD

The study comprised 63 children with T1DM (31 females, 32 males; mean age 9 y 11 mo,SD 4 mo) and 92 comparison children without diabetes (40 females, 52 males;mean age 9 y 9 mo,SD 3 mo). Children were included if T1DM had been diagnosed before the age of 5 years and if they were aged between 9 and 10 years at the time of study. Children were not included if their native language was not Finnish and if they had a diagnosed neurological disorder that affected their cognitive development. Among the T1DM group, 37 had and 26 had not experienced severe hypoglycaemia and 26 had avoided severe hypoglycaemia. Severe hypoglycaemia, diabetic ketoacidosis(DKA), and glycaemic control were used as T1DM-related factors. Task performance in reading, spelling, and mathematics was compared among the three groups, and the effects of the T1DM-related factors were analysed with general linear models.

RESULTS

The groups with (p<0.001) and without (p=0.001) severe hypoglycaemia demonstrated a poorer performance than the comparison group in spelling, and the group without severe hypoglycaemia showed a poorer performance than the comparison group in mathematics (p=0.003).Severe hypoglycaemia, DKA, and recent glycaemic control were not associated with poorer skills,but poorer first-year glycaemic control was associated with poorer spelling (p=0.013).

INTERPRETATION

An early onset of T1DM can increase the risk of learning problems, independently of the history of severe hypoglycaemia or DKA. Poorer glycaemic control after the first year of T1DM is associated with a poorer acquisition of academic skills indicating the effect of the timing of metabolic aberrations on cognitive development.