Glycemia, Blood Pressure Management Could Slow Cognitive Decline in Older Adults With T1D

Data from a longitudinal study reveal poor glycemic control and blood pressure management may contribute to cognitive decline in older patients with type 1 diabetes.

According to study results published in The Lancet. Diabetes & Endocrinology, cognitive function declines with aging among individuals with type 1 diabetes (T1D). However, because associations were seen between glycemia and blood pressure levels and cognitive decline, the authors suggest better management of these factors may help preserve cognitive function.

“Advances in the treatment of type 1 diabetes have led to a dramatic improvement in life expectancy, with a corresponding increased susceptibility to aging-related conditions, including cognitive dysfunction and dementia,” they wrote.

Previous studies also demonstrated children and young adults with T1D, poor glycemic control, and microvascular complications reported modest cognitive dysfunction.

To determine whether and to what extent this decline progresses as patients age, the investigators assessed data from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications (DCCT/EDIC) study. DCCT/EDIC consists of the largest cohort of patients with T1D thoroughly phenotyped for all diabetes complications.

Within this study, longitudinal cognitive and biomedical data have been collected for over 32 years from individuals aged 13 to 39 yers at baseline. Currently, participants have a median age of 59.

Glycemic excursions (higher persistent glycated hemoglobin [A1C] levels and episodes of severe hypoglycemia), in addition to microvascular and macrovascular risk factors and complications, were measured throughout the study window.

A total of 1051 patients were enrolled in the study, while participants completed cognitive assessments at baseline (median age, 27 years), and 2, 5, 18 and 32 years later.

“Over 32 years of follow-up, we found substantive declines in memory and psychomotor and mental efficiency,” the authors wrote.

Analyses revealed:

  • A total of 1608 episodes of severe hypoglycemia leading to coma or seizure were reported in 482 participants; 398 reported between 1 and 5 events and 84 reported more than 5 events
  • Between 18 and 32 years of follow-up, the decline in psychomotor and mental efficiency was 5 times larger than the change from baseline to year 18
  • Independent of other risk factors and comorbidities, exposure to higher A1C levels, more episodes of severe hypoglycemia, and elevated systolic blood pressure were all associated with greater decrements in psychomotor and mental efficiency that were most notable by year 32 (P <.0001)
  • The combined effect of the presence of these 3 risk factors is the equivalent to an additional 9.4 years of age

However, patients with the best glycemic control did not demonstrate any decreases in psychomotor and mental efficiency throughout the observation period.

“As our participants enter the period of aging-related neuropathology, a history of 1 or more severe hypoglycemic events appears to be associated with a significant decline in psychomotor and mental efficiency,” the researchers wrote.

The lack of a comparison group without diabetes marks a limitation to this study, and findings may not be generalizable to other populations with diabetes, as the participants were largely White and were highly motivated to monitor their health. In addition, the investigators cannot rule out that cognitive ability may have affected self-management of diabetes and worse clinical outcomes could have been due to cognitive dysfunction and not the reverse.

“This study reveals the cognitive path expected for individuals with long-standing type 1 diabetes as they age and brings into clear view the value of better management of glycemia and hypertension to change this course,” they concluded.

Reference

Jacobson AM, Ryan CM, Braffett BH, et al. Cognitive performance declines in older adults with type 1 diabetes: results from 32 years of follow-up in the DCCT and EDIC study. Lancet Diabetes Endocrinol. Published online May 27, 2021. doi:10.1016/S2213-8587(21)00086-3