Hypoglycemic, hyperglycemic events increase dementia risk in adults with type 1 diabetes

Severe hypoglycemic and hyperglycemic events correlated with increased risk for dementia among older adults with type 1 diabetes, according to a longitudinal cohort study of more than 2,800 patients published in Neurology.

“For people with diabetes, both severely high and low blood sugar levels are emergencies and both extremes can largely be avoided. However, when they do occur, they can lead to coma, increased hospitalization and even death,” Rachel A. Whitmer, PhD, of the division of epidemiology at University of California Davis School of Medicine, said in a press release. “People with type 1 diabetes are living longer than before, which may place them at risk of conditions such as dementia. If we can potentially decrease their risk of dementia by controlling their blood sugar levels, that could have beneficial effects for individuals and public health overall."

Whitmer and colleagues investigated a possible association between severe hypoglycemic and hyperglycemic events and long-term dementia risk in older adults with type 1 diabetes.

The longitudinal cohort study included 2,821 patients with type 1 diabetes who were enrolled in an integrated healthcare delivery system between 1997 and 2015. The mean age of the patients at baseline was 56 years; 14% had a history of severe hypoglycemia, 12% had a history of severe hyperglycemia, and 3% had both severe hypoglycemia and hyperglycemia.

The researchers recorded diabetic events requiring hospitalization or an ED visit according to patients’ medical records and followed patients for a dementia diagnosis until September 2015. Whitmer and colleagues applied Cox proportional hazard models adjusted for factors that included age, sex, race/ethnicity, HbA1c, depression, stroke and nephropathy.

Over a mean follow-up period of 6.9 years, the researchers found that 5.4% of patients developed dementia. In fully adjusted models, individuals with a history of hypoglycemic events exhibited a 66% greater risk for developing dementia compared with those without hypoglycemia (HR = 1.66; 95% CI, 1.09-2.53). Patients with hyperglycemic events had greater than double the risk for dementia (HR = 2.11; 95% CI, 1.24-3.59) compared to those without. Moreover, among patients with both severe hypoglycemia and hyperglycemia, the researchers observed a six-fold greater risk for dementia compared to those with a history of neither event (HR = 6.2; 95% CI, 3.02-12.7).

The researchers also examined dementia incidence rates. After adjusting for age, they observed an incidence rate for dementia of 26.5 cases per 1,000 person-years among people with hypoglycemic events compared with 13.2 cases among people without such events. Whitmer and colleagues reported an incidence rate for dementia of 79.6 cases per 1,000 person-years among those with hyperglycemic events compared with 13.4 cases among people without such events, according to the press release. The incidence rate for dementia among people with both hypoglycemic and hyperglycemic events at various times was 98.5 per 1,000 person-years compared with 12.8 per 1,000 person-years for people who experienced neither type of event.

“Our findings suggest that exposure to severe glycemic events may have long-term consequences on brain health and should be considered additional motivation for people with diabetes to avoid severe glycemic events throughout their lifetime,” Whitmer said in the release.

Reference:

American Academy of Neurology. Blood sugar highs and lows linked to greater dementia risk in type 1 diabetes. Available at: https://www.aan.com/PressRoom/Home/PressRelease/4898. Accessed June 2, 2021.