Hypo- and hyperglycaemia are dreaded complications of type 1 diabetes. According to the results of a US cohort study, those who had to be treated in hospital during the course of their disease have a significantly increased risk of developing dementia in advanced age.
It is well known that the brain reacts particularly sensitive to glucose fluctuations, as glucose is the most important energy supplier for the nerve cells. If there is not enough glucose available in the case of severe hypoglycaemia, the well-known failures of brain functions up to and including coma occur. But an oversupply of glucose can also have a damaging effect on the brain, as the brain cells are deprived of fluid by the increased osmolality. In severe cases, this can result in a diabetic coma.
In the cohort study, epidemiologist Rachel Whitmer of the Davis School of Medicine in Sacramento and her research group analysed the insurance data of 2,821 patients with type 1 diabetes (mean age 56 years). 398 patients (14%) had to be hospitalised at least once for severe hypoglycaemia in the preceding 20 years - 335 patients (12%) were hospitalised with severe hyperglycaemia in the same period. 87 patients (3%) had been hospitalised with both forms of metabolic derailment. 153 patients (5.4%) had developed dementia during the follow-up period of 6.9 years on average.
Patients with a history of severe hypoglycaemia had a 66% higher risk of developing dementia compared to type 1 diabetics without this complication, regardless of factors such as age, gender and ethnicity. This corresponds to an incidence of 26.5 cases per 1,000 person-years compared to 13.2 per 1,000 person-years in insured persons with type 1 diabetes without complications.
Patients with an inpatient hyperglycaemic event were at even greater risk - here the risk of dementia was more than twice as high (HR 2.11) and the incidence was 79.6 per 1,000 patient-years. Patients who were hospitalised with both hypo- and hyperglycaemia fared worst. The risk of dementia was six times higher here and the incidence rose to 98.5 per 1,000 person-years.
Conclusion: Good metabolic control in type 1 diabetes with avoidance of hypo- and hyperglycaemia can also make an important contribution to dementia prevention in this group of people.
Reference:
Rachel A. Whitmer et al: Association of Type 1 Diabetes and Hypoglycemic and Hyperglycemic Events and Risk of Dementia; Neurology (2021)