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

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.

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.

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).

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