Type 1 Diabetes Linked to Neurological Changes in Children

Nelly Mauras, MD

While many studies have linked inadequate glycemic control to declines in neurocognitive health among older adults with type 2 diabetes, new research suggests type 1 diabetes was linked to lower brain volume, verbal IQ, and overall IQ in children.

A study lasting nearly 8 years with more than 200 children, results indicate children with type 1 diabetes had detectable changes in brain volumes and cognitive scores that persist over time and led investigators to call for further research into the phenomenon.

"Our findings indicate that, despite improved glycemic control now possible with emerging technologies, individuals with T1D are at risk for cognitive dysfunction," said Nelly Mauras, MD, a principal investigator of the study and Chief of the Division of Endocrinology, Diabetes & Metabolism at the Nemours Children's Health System in Jacksonville, Florida, and Professor of Pediatrics at the Mayo College of Medicine, in a statement. "Our longitudinal data support the hypothesis that the brain is a target of diabetes complications in young children. Whether these changes can be reversed with scrupulous diabetes control requires further study."

To further understand how presence of type 1 diabetes might impact neurologic and cognitive differences in children, investigators designed the current study as an assessment of these differences among children from a cohort of Diabetes Research in Children Network consortium. In total, 144 children with type 1 diabetes and 72 age-matched controls without diabetes were included in the study.

All children included in the study underwent an unsedated MRI and had cognitive testing performed up to 4 times over a follow-up period that ranged from 5.3-7.8 (mean 6.4±0.4) years. The mean age of patients at baseline was 7.0±1.7 years and 46% were female.

Upon analysis, investigators found total brain, gray matter, and white matter volumes were lower among the diabetes at ages of 6, 8, 10, and 12 years. Specific differences in total brain volume were -15,410, -21,159, -25,548, -28,577 mm3 x 103 at 6, 8, 10, and 12 years, respectively (P <.05). Specific differences in gray matter volumes were -8,604 (-20,711, 3,504), -11,869 (-23,883, 145), -14,375 (-26,730, -2,021), and -16,123 (-28,662, -3,584) at 6, 8, 10, and 12 years, respectively. Specific differences in white matter volumes were 26,426 (215,986, 3,133), -8,486 (-18,339, 1,367), -10,430 (-20,724, -136), -12,259 (-22,877, -1,640) at 6, 8, 10, and 12 years, respectively.

Further analysis indicated children in the diabetes group also had lower full-scale and verbal intelligence IQs at 6, 8, 10, and 12 years. Specific differences in full-scale IQ were -4.15, -3.81, -3.46, -3.11 at 6, 8, 10, and 12 years, respectively (P <.05). Specific differences in verbal IQ were -3.83 (-7.06, -0.60), 23.90 (-6.73, 21.06), 23.97 (26.72, 21.22), 24.04 (27.04, 21.03) at 6, 8, 10, and 12 years, respectively (P <.02). Investigators noted differences between the groups at baseline appeared to persist or increase over time. Additionally, brain volumes and cognitive scores negatively correlated with a life-long HbA1c index and increased sensor glucose in diabetes.

"Although differences in cognition were mild - around 4 IQ points - this magnitude is similar to other conditions that affect the brain," said Mauras. "We know that T1D can cause complications in multiple organ systems, and our study adds knowledge to earlier research which suggested that glucose level variation in T1D can negatively affect brain development, beginning in childhood."

This study, “Impact of Type 1 Diabetes in the Developing Brain in Children: A Longitudinal Study,” was published in Diabetes Care.