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Diabetes linked to epilepsy

Researchers find three-fold increase in epilepsy in type 1 diabetics

Mark Gould

Friday, 01 April 2016

People with type 1 diabetes have a three-time increased risk of developing epilepsy later in life. Researchers say immune abnormalities, brain lesions, genetic factors and metabolic abnormalities are all potential causes for the link.

Writing in Diabetologia,* the journal of the European Association for the Study of Diabetes (EASD), Dr I-Ching Chou, from China Medical University Children’s Hospital, Taichung, Taiwan, and colleagues evaluated the relationship between type 1 diabetes and epilepsy in Taiwan.

Data from the Taiwan National Health Insurance Research Database were used to conduct retrospective analyses. The study cohort contained 2,568 patients with type 1 diabetes, each of whom was frequency-matched by sex, urbanisation of residence area and index year with ten control patients without type 1 diabetes.

Computer modelling was used to estimate the effects of type 1 diabetes on epilepsy risk. In patients with type 1 diabetes, the risk of developing epilepsy was significantly higher than that in patients without type 1 diabetes. After adjustment for potential confounders, the type 1 diabetes cohort was 2.84 times more likely to develop epilepsy than the control cohort.

The authors say: “This result is consistent with those of previous studies in that epilepsy or seizures are observed in many autoimmune or inflammatory disorders and are linked to the primary disease, or secondary to pro-inflammatory processes.”

Type 1 diabetes is one of the most common autoimmune disorders in children, with a 3% annual increase in the global incidence rate since the 1980s. In recent decades, the incidence of type 1 has increased in children and adolescents, particularly those aged younger than 5 years.

They say that as both hyperglycaemia and hypoglycaemia commonly occur in elderly people with diabetes this can alter the balance between the inhibition and excitation of neuronal networks and cause focal motor seizures. "In addition, we found that younger age was associated with an increased risk of developing epilepsy. Previous studies have suggested severe hypoglycaemia, young age and early onset as critical risk factors for brain abnormalities… The current results could provide evidence to facilitate the prognosis of children with type 1 diabetes.”

They conclude: “Patients with type 1 diabetes are at an increased risk of developing epilepsy. Metabolic abnormalities of type 1 diabetes, such as hyperglycaemia and hypoglycaemia, may have a damaging effect on the central nervous system and be associated with significant long-term neurological consequences. The causative factors between type 1 diabetes and the increased risk of epilepsy require further investigation.”

* I-Ching Chou, et al. Risk of epilepsy in type 1 diabetes mellitus: a population-based cohort study. Diabetologia pp 1-8. First online: 31 March 2016

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