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

George E Dafoulas, Konstantinos Toulis, Dougall Mccorry, Balachandran Kumarendran, G Neil Thomas, Brian H. Willis, Krishna Gokhale, Georgios Gkoutos, Parth Narendran, Krishnarajah Nirantharakumar

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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.

Original languageEnglish
Pages (from-to)258-261
Number of pages4
Issue number2
Early online date31 Oct 2016
Publication statusPublished - Feb 2017


  • Epilepsy
  • Hypoglycaemia
  • Insulin
  • Seizures
  • Type 1 diabetes mellitus


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