Type 1 Diabetes May Increase Epilepsy Risk Threefold

Marlene Busko

April 02, 2016

Children and adolescents with type 1 diabetes are nearly three times more likely to develop epilepsy than their peers without type 1 diabetes, according to a large insurance-claims study from Taiwan.

The findings are consistent with other, limited research that suggest a link between type 1 diabetes and epilepsy, but more research is needed to determine how this occurs, according to I-Ching Chou, MD, from China Medical University Children's Hospital, in Taichung, Taiwan, and colleagues. The researchers reported their results in an article published online March 31, 2016 in Diabetologia.

"The pathogenetic mechanisms of neurological diseases [such as epilepsy] remain unknown but may be associated with significant long-term neurological sequelae," they stress. Thus, the "causative factors between type 1 diabetes and the increased risk of epilepsy require further investigation," they conclude.

"Teasing out the causes of seizures is difficult to do retrospectively in an administrative database," Kenneth Mandl, MD, MPH, from Harvard Medical School and Boston Children's Hospital, Massachusetts, told Medscape Medical News. However, as previously reported, his group performed a similar analysis of US insurance-claims data and found that patients who had any of 12 autoimmune diseases had an increased risk of epilepsy and those with type 1 diabetes had a 5.2-fold increased risk of epilepsy.

Dr Mandl agrees that the relationship between diabetes and epilepsy risk "should certainly be studied further," ideally "in populations where coding can be confirmed with clinical review and characterization of the seizures."

Could Diabetes Explain Some Idiopathic Seizures?

About 25% to 45% of epilepsy cases can be traced to structural abnormalities, metabolic disturbances, and genetic factors, but early research has also suggested that diabetes might explain some idiopathic seizures, Dr Chou and colleagues write. Yet research examining a potential link between type 1 diabetes and epilepsy has been limited, and findings have been inconsistent.

Therefore, the researchers performed a population-based cohort study using 12-year data from the Taiwan National Health Insurance Research Database (NHIRD), which includes virtually all residents in Taiwan (23 million in 1998).

They identified 2568 children and adolescents aged 18 and younger diagnosed with new-onset type 1 diabetes between January 1, 2000 and December 31, 2009, and 25,680 youngsters without diabetes (comparator group).

Those in the comparator group were slightly older (mean age, 11.1 vs 10.4 years; P < .0001) and less likely to have an intellectual disability (0.7% vs 1.3%; P < .05) or prior epilepsy (1.1% vs 1.6%; P < .05) compared with individuals with type 1 diabetes.

There were 59 cases of new-onset epilepsy in patients with type 1 diabetes, and 181 cases of new-onset epilepsy in the comparator group during follow-up. This translated into an incidence of epilepsy of 33.7 per 10,000 person-years for those with type 1 diabetes vs 10.4 per 10,000 person-years for individuals without type 1 diabetes.

After adjustment for age, sex, urban vs rural dwelling, prior epilepsy, intellectual disabilities, low birth weight, and head injury, the risk of epilepsy in those with type 1 diabetes was 2.84-fold higher than the comparator group (hazard ratio [HR], 2.84; 95% CI, 2.11- 3.83).

Those with type 1 diabetes without hypoglycemia had a 2.67-fold increased risk of developing epilepsy during follow-up vs the comparator group, whereas those with type 1 diabetes and hypoglycemia had a much greater 16.5-fold increased risk of developing epilepsy (P for trend < .0001).

These findings support the hypothesis that "metabolic abnormalities of type 1 diabetes, such as hyperglycemia and hypoglycemia, may have a damaging effect on the central nervous system and be associated with significant long-term neurological consequences," write Dr Chou and colleagues.

The authors and Dr Mandl have reported no relevant financial relationships.

Diabetologia. Published online March 31, 2016. Article


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