Type 1 diabetes and epilepsy: more than a casual association?

Type 1 diabetes and the risk of epilepsy: A meta-analysis

AIMS/INTRODUCTION

An overrepresentation of epilepsy has been suggested in patients with type 1 diabetes (T1D). This meta-analysis was conducted to evaluate if type 1 diabetes is associated with a higher incidence of epilepsy.

MATERIALS AND METHODS

Longitudinal observational studies which are relevant to the purpose of the meta-analysis were screened and obtained by searching PubMed, Embase, and Web of Science databases. Random-effects models were used when significant heterogeneity was observed; otherwise, fixed-effects models were used.

RESULTS

Six observational studies involving 10 datasets of 8,001,899 participants were included, with six datasets including children and only one dataset including older people. Among them, 100,414 (1.25%) had type 1 diabetes. During the follow-up duration of 5.4-15.2 years (mean: 9.5 years), 98,644 cases (1.23%) of epilepsy were observed. Compared with participants with normoglycemia, those with type 1 diabetes were shown to have a higher incidence of epilepsy (risk ratio [RR]: 2.41, 95% confidence interval 1.69-3.44, P < 0.001; I2  = 95%) after adjustment of potential confounding variables including age and sex. Subgroup analysis showed consistent results in nested case-control and retrospective cohort studies, and in studies of children, non-elderly adult, and older participants (P for subgroup difference = 0.42 and 0.07). In addition, a stronger association of type 1 diabetes and epilepsy was suggested in studies with follow-up duration <10 years compared with those ≥10 years (RR: 3.34 vs 1.61, P for subgroup difference < 0.001).

CONCLUSION

Patients with type 1 diabetes may have a higher risk of epilepsy, which was mainly driven by datasets including children.

Data extraction for epidemiological research (DExtER): a novel tool for automated clinical epidemiology studies

The use of primary care electronic health records for research is abundant. The benefits gained from utilising such records lies in their size, longitudinal data collection and data quality. However, the use of such data to undertake high quality epidemiological studies, can lead to significant challenges particularly in dealing with misclassification, variation in coding and the significant effort required to pre-process the data in a meaningful format for statistical analysis. In this paper, we describe a methodology to aid with the extraction and processing of such databases, delivered by a novel software programme; the "Data extraction for epidemiological research" (DExtER). The basis of DExtER relies on principles of extract, transform and load processes. The tool initially provides the ability for the healthcare dataset to be extracted, then transformed in a format whereby data is normalised, converted and reformatted. DExtER has a user interface designed to obtain data extracts specific to each research question and observational study design. There are facilities to input the requirements for; eligible study period, definition of exposed and unexposed groups, outcome measures and important baseline covariates. To date the tool has been utilised and validated in a multitude of settings. There have been over 35 peer-reviewed publications using the tool, and DExtER has been implemented as a validated public health surveillance tool for obtaining accurate statistics on epidemiology of key morbidities. Future direction of this work will be the application of the framework to linked as well as international datasets and the development of standardised methods for conducting electronic pre-processing and extraction from datasets for research purposes.

Drivers for the comorbidity of type 2 diabetes mellitus and epilepsy: A scoping review

Epilepsy, a common neurologic condition, is associated with a greater prevalence of type 2 diabetes mellitus (T2DM). We examined potential drivers for the comorbidity of epilepsy and T2DM in an attempt to elucidate possible biological mechanisms underlying the development of processes in individuals. We searched PubMed and Medline up to December 2019. Our search yielded 3361 articles, of which 82 were included in the scoping review. We reviewed articles focusing on the association of epilepsy and T2DM, drivers, and biological mechanisms. We found that epilepsy is associated with obesity and obesity is associated with T2DM. Treatment with valproate (either sodium or acid) is associated with weight increase and hyperinsulinemia, while topiramate causes weight loss. People with epilepsy are less likely to exercise, which is protective against obesity. Mitochondrial dysfunction and adiponectin deficiency are common to epilepsy and T2DM. One possible mechanism for the comorbidity is mitochondrial dysfunction and adiponectin deficiency, which promotes epilepsy, obesity, and T2DM. Another possible mechanism is that people with epilepsy are more likely to be obese because of the lack of exercise and the effects of some antiseizure medications (ASMs), which makes them susceptible to T2DM because of the development of mitochondrial dysfunction and adiponectin deficiency. A third mechanism is that people with epilepsy have greater mitochondrial dysfunction and lower adiponectin levels than people without epilepsy at baseline, which may exacerbate after treatment with ASMs. Future research involving a combined genetic and molecular pathway approach will likely yield valuable insight regarding the comorbidity of epilepsy and T2DM.

Association between high titers of glutamic acid decarboxylase antibody and epilepsy in patients with type 1 diabetes mellitus: A cross-sectional study

PURPOSE

Individuals with type 1 diabetes mellitus (T1D) are at higher risk of epilepsy. T1D is a progressive immune-mediated disease and the etiology of epilepsy remains unknown in most. Glutamic acid decarboxylase (GAD) catalyzes GABA formation. GABA-secreting neurons and pancreatic beta cells are the major cells expressing GAD.

METHODS

Cross-sectional study. Patients with T1D from a multiethnic population underwent GADA measurement to investigate possible association between T1D and epilepsy of unknown etiology.

RESULTS

T1D patients were analyzed (n = 375). Overall frequency of epilepsy was 5.9% (n = 22). Frequency of epilepsy of unknown etiology was 3.2% (n = 12). Of these, 8 (2.1%) had idiopathic generalized epilepsy (IGE) and 4 (1.1%) MRI-negative temporal lobe epilepsy (TLE). Patients with T1D and epilepsy of unknown etiology did not show differences in GADA frequency (83.3% vs 50%; p = 0.076); however, their titers were higher (106.9 ± 136.5 IU/mL; median 7; IQR 1.65-256 vs 10.2 ± 14.5 IU/ml; median 4.3; IQR 1.9-8.9; p = 0.019) compared to patients without epilepsy. Moreover, epilepsy of unknown etiology was associated with GADA titers ≥ 100 UI/mL [odds ratio (OR) 4.42, 95% CI 2.36-8.66].

CONCLUSION

Epilepsy frequency was elevated in patients with T1D and multiethnic background. Presence of epilepsy of unknown etiology was associated with high titers of GADA in this population with long-standing T1D, which has different ethnic and genetic background compared to previous studies. Further prospective studies are required to identify if GADA presence or its persistence are directly responsible for epilepsy in individuals with T1D.

Epilepsy in children with type 1 diabetes mellitus: Pathophysiological basis and clinical hallmarks

We provide an overview on the current knowledge about the association between epilepsy and type 1 diabetes mellitus (T1DM). People with T1DM have a 2-6-fold higher risk of epilepsy than the general population. The onset of T1DM anticipates the onset of epilepsy by a mean period between 1,5 and 2,8 years. These two disorders share four potential distinct pathogenic factors: a) genetic predisposition; b) factors involved in autoimmune responses (i.e. anti-glutamic acid decarboxylase antibodies-GADAbs); c) effects of hypo/hyperglycaemia; d) cerebrovascular damages resulting in ischaemic processes. Seizures semiology prominently includes focal (up to patterns of epilepsia partialis continua) or secondarily generalized seizures but also reflex seizures and various forms of generalized seizures. EEG abnormalities are more common in people with an inappropriate metabolic control with a prominent involvement of fronto-temporal regions. Epilepsy management does not differ between patients with and without diabetes and insulin, nutritional recommendations and physical activity may also produce significant benefits on seizures control. Possible therapeutic alternatives in selected cases include immunosuppressive drugs (in patients with GADAbs) and ketogenic diet.

GAD65 autoantibody characteristics in patients with co-occurring type 1 diabetes and epilepsy may help identify underlying epilepsy etiologies

Background

Autoantibodies against the smaller isoform of glutamate decarboxylase (GAD65Ab) reflect autoimmune etiologies in Type 1 diabetes (T1D) and several neurological disorders, including Stiff Person Syndrome (SPS). GAD65Ab are also reported in cases of epilepsy, indicating an autoimmune component. GAD65Ab in patients with co-occurring T1D, epilepsy or SPS may be part of either autoimmune pathogenesis. To dissect the etiologies associated with GAD65Ab, we analyzed GAD65Ab titer, epitope specificity and enzyme inhibition in GAD65Ab-positive patients diagnosed with epilepsy (n = 28), patients with epilepsy and T1D (n = 10), patients with SPS (n = 20), and patients with T1D (n = 42).

Results

GAD65Ab epitope pattern in epilepsy differed from T1D and SPS patients. Four of 10 patients with co-occurring T1D and epilepsy showed GAD65Ab profiles similar to T1D patients, while lacking GAD65Ab characteristics found in GAD65Ab-positive epilepsy patients. One of these patients responded well to anti-epileptic drugs (AEDs), while another patient did not require medication for seizure control. The third patient was refractory due to a diagnosis of meningioma. The response of the remaining patient to AEDs was unknown. GAD65Ab in the remaining six patients with T1D and epilepsy showed profiles similar to those in epilepsy patients.

Conclusions

Different autoimmune responses associated with T1D, epilepsy and SPS are reflected by disease-specific GAD65Ab patterns. Moreover, the epileptic etiology in patients diagnosed with both T1D and epilepsy may present two different etiologies regarding their epileptic condition. In one group T1D co-occurs with non-autoimmune epilepsy. In the other group GAD65Ab are part of an autoimmune epileptic condition.

Type 1 diabetes mellitus and risk of incident epilepsy: a population-based, open-cohort study

AIMS/HYPOTHESIS

The aim of this research was to explore the relationship between incident epilepsy and type 1 diabetes in British participants.

METHODS

Using The Health Improvement Network database, we conducted a retrospective, open-cohort study. Patients who were newly diagnosed with type 1 diabetes mellitus at the age of ≤40 years were identified and followed-up from 1 January 1990 to 15 September 2015. These patients, identified as not suffering from epilepsy at the time of diagnosis, were randomly matched with up to four individuals without type 1 diabetes mellitus, based on age, sex and participating general practice. A Cox regression analysis was subsequently performed using Townsend deprivation index, cerebral palsy, head injury and learning disabilities as model covariates.

RESULTS

The study population consisted of a total of 24,610 individuals (4922 with type 1 diabetes and 19,688 controls). These individuals were followed up for a mean of 5.4 years (approximately 132,000 person-years of follow up). Patients with type 1 diabetes were significantly more likely to be diagnosed with epilepsy during the observation period compared with controls (crude HR [95% CI]: 3.02 [1.95, 4.69]). The incidence rate was estimated to be 132 and 44 per 100,000 person-years in patients and controls, respectively. This finding persisted after adjusting for model covariates (adjusted HR [95% CI]: 3.01 [1.93, 4.68]) and was also robust to sensitivity analysis, excluding adult-onset type 1 diabetes mellitus.

CONCLUSIONS/INTERPRETATION

Patients with type 1 diabetes are at approximately three-times greater risk of developing epilepsy compared with matched controls without type 1 diabetes. This should be considered when investigating seizure-related disorders in patients with type 1 diabetes mellitus.

Diabetes and epilepsy in children and adolescents

Over the last years, there has been an increasing interest in the potential association between type 1 diabetes (T1D) and epilepsy. Both T1D and epilepsy are common conditions in children and adolescents, and therefore, their association might represent simply a coincidence or be related to common underlying mechanisms with a potential causal relationship. Few epidemiological studies have been performed in the pediatric population, and they have reached discordant conclusions, with some studies reporting an increased prevalence of epilepsy in children and adolescents with T1D, whereas others have not confirmed this finding. Several mechanisms could explain the occurrence of epilepsy in young people with T1D, such as metabolic abnormalities (hypo/hyperglycemia) and autoantibodies, along with a genetic predisposition and the presence of brain lesions/damage. Further studies are required to better define whether there is a causal relationship between the two conditions and to understand the underlying mechanisms.

Seizures and epilepsy in hypoglycaemia caused by inborn errors of metabolism

AIM

The aim of the study was to characterize seizures and epilepsy related to hypoglycaemia.

METHOD

We analyzed the files of 170 consecutive patients referred for hypoglycaemia (onset 1h to 4y) caused by inborn errors of metabolism (glycogen storage disease type I, fatty acid β-oxidation disorders, and hyperinsulinism).

RESULTS

Ninety patients (42 males and 48 females; 38 neonates and 52 infants/children) had brief hypoglycaemic seizures (68%) or status epilepticus (32%). Status epilepticus occurred earlier (mean 1.4d) than brief neonatal seizures (4.3d, p=0.02). Recurrent status epilepticus followed initial status epilepticus and was often triggered by fever. Epilepsy developed in 21 patients. In 18 patients, epilepsy followed hypoglycaemic status epilepticus and began with shorter delay when associated with grey matter lesions (1.9mo, standard error of the mean [SEM] 1mo) than with white matter damage (3.3y [SEM 1y], p=0.003). Three patients with hyperinsulinism developed idiopathic epilepsy following brief neonatal seizures.

INTERPRETATION

Brief neonatal hyperinsulinaemic hypoglycaemic seizures have characteristics of idiopathic neonatal seizures. Neonatal status epilepticus should be prevented by the systematic measurement of glucose blood level. Recurrent seizures never consist of status epilepticus when following brief initial seizures. Epilepsy is symptomatic of brain damage with shorter delay in the case of grey rather than white matter lesions, except in a few idiopathic cases in which epilepsy and hyperinsulinism may share a common genetic background.

Epilepsy in systemic autoimmune disorders

Autoimmunity and inflammation have been implicated as causative factors of seizures and epilepsy. Autoimmune disorders can affect the central nervous system as an isolated syndrome or be part of a systemic disease. Examples of systemic autoimmune disorders include systemic lupus erythematosus, antiphospholipid syndrome, rheumatic arthritis, and Sjögren syndrome. Overall, there is a 5-fold increased risk of seizures and epilepsy in children with systemic autoimmune disorders. Various etiologic factors have been implicated in causing the seizures in these patients, including direct inflammation, effect on blood vessels (vasculitis), and production of autoantibodies. Potential treatments for this autoimmune injury include steroids, immunoglobulins, and other immune-modulatory therapies. A better understanding of the mechanisms of epileptogenesis in patients with systemic autoimmune diseases could lead to targeted treatments and better outcomes.

Seizures and type 1 diabetes mellitus: current state of knowledge

In this review, we will try to analyze the possible coexistence between epilepsy or seizures and type 1 diabetes mellitus (T1DM), in order to establish if there is more than a casual association, and to investigate possible mechanisms underlying this link. Anti-glutamic acid decarboxylase antibodies (GAD-Abs) have been associated with T1DM and a great number of neurological diseases such as epilepsy. Epilepsy can be a feature of a large variety of autoimmune or inflammatory disorders. GAD-Abs can have a role at the basis of the possible link between epilepsy and T1DM, although their real pathogenetic mechanism in neurological diseases is still unknown. Metabolic conditions such as hypoglycemia and hyperglycemia, common problems in diabetic patients, may be also implicated, even if their underlying mechanism is minimally understood.

Association of epilepsy and type 1 diabetes mellitus in children and adolescents: is there an increased risk for diabetic ketoacidosis?

OBJECTIVE

To estimate the prevalence of epilepsy and possible risk factors in children and adolescents with diabetes mellitus.

STUDY DESIGN

We conducted an observational cohort study based on the Diabetes Patienten Verlaufsdokumentation database including data from 45 851 patients (52% male) with type 1 diabetes mellitus, age 13.9 ± 4.3 years (mean ± SD) and duration of diabetes mellitus 5.4 ± 4.2 years. The database was searched for the concomitant diagnosis of epilepsy or epileptic convulsions and for antiepileptic medication.

RESULTS

A total of 705 patients with epilepsy were identified, giving a prevalence of 15.5 of 1000. A total of 375 patients were treated with antiepileptic medication, and 330 patients were without anticonvulsive therapy. Patients with epilepsy were younger at onset of diabetes mellitus and shorter than patients without epilepsy, and their weight and body mass index were comparable. No difference could be demonstrated for metabolic control, type of insulin treatment, insulin dose, and prevalence of B-cell specific autoantibodies. The frequency of severe hypoglycemia was lower in patients treated with antiepileptic medication. The risk for diabetic ketoacidosis was almost double in patients with epilepsy compared with patients with type 1 diabetes mellitus alone (P < .01).

CONCLUSION

Children and adolescents with diabetes mellitus show an increased prevalence of epileptic seizures. For unknown reasons, there is an association between epilepsy and diabetic ketoacidosis in children with type 1 diabetes mellitus.

Study of prevalence of epilepsy in children with type 1 diabetes mellitus

PURPOSE

To evaluate the prevalence of epilepsy in children (<16 yrs) with type 1 diabetes.

METHODS

A review of clinical notes and investigations was carried out on all the children with type 1 diabetes who were under follow-up in the Paediatric Diabetes clinic at Alder Hey Children's Hospital in the year 2010.

RESULTS

Of 285 children aged <16 years with type 1 diabetes, six also had epilepsy giving a prevalence of 21/1000. This is approximately six times greater than the prevalence of epilepsy in the general population of children in UK.

CONCLUSION

Epilepsy appears to occur more frequently in children with type 1 diabetes than in the general paediatric population.

Systemic and neurologic autoimmune disorders associated with seizures or epilepsy

In this article, we review the incidence and significance of seizures in well-established autoimmune disorders, including multiple sclerosis (MS), diabetes mellitus, celiac disease, thyroid disease, and systemic lupus erythematosus (SLE). The five following presentations discuss the incidence and possible pathogenesis of epilepsies that are found in these well-known autoimmune conditions. There is a large body of evidence describing the clinical presentation of seizures with MS and SLE, and showing that refractory epilepsy can complicate these already challenging disorders. However, the mechanisms involved are complex and generally not well understood. Neurologic syndromes, including seizure disorders, can also be a feature of celiac disease (CD) or subclinical CD, sometimes associated with cerebral calcification. The association between type-1 diabetes mellitus (T1DM) and epilepsy is unclear and requires more definitive epidemiologic analysis, despite the fact that antibodies to glutamic acid decarboxylase may provide a link between the two conditions. The association between thyroid disorders and encephalopathies, often termed Hashimoto's encephalopathy, is well known but the pathogenic significance of antithyroid antibodies in this condition is still debated. In general, the relationships between autoimmune mechanisms and seizures in these conditions are unclear; the seizures are likely to be caused by a variety of mechanisms, including ischemia, neuronal damage, and specific and nonspecific immunity.