Serum brain-derived neurotrophic factor and neurocognitive function in children with type 1 diabetes.

Background/purpose: This study aimed to clarify whether brain-derived neurotrophic factor (BDNF) is a biomarker for cognitive dysfunction in children with type 1 diabetes.

Methods: We conducted a cross-sectional case-control study of children aged between 6 and 18 years with type 1 diabetes and healthy volunteers. Serum BDNF level was measured in all of the studied children, and they all underwent intelligence tests with the Wechsler Intelligence Scale for Children, Fourth Edition (WISC-IV). We further compared the cognitive function and BDNF levels in the diabetic children with positive glutamic acid decarboxylase 65 antibody (GAD65-Ab) and those with negative GAD65-Ab.

Results: Forty-five children with type 1 diabetes (mean age 14.0 ± 2.6 years, 42% male) and 50 normal controls (mean age 13.2 ± 2.3 years, 54% male) were recruited. The serum BDNF level was significantly lower in the diabetes group than in the controls (15.92 ± 7.2 vs. 18.5 ± 5.1 ng/mL, respectively, t = -2.03, p = 0.045) and much lower in the subgroup with GAD65-Ab positive type 1 diabetes. The average Full-Scale IQ, verbal comprehension, perceptual reasoning and working memory scores in the diabetes group were significantly lower than in the controls (all p < 0.05). Among the children with type 1 diabetes, poor glycemic control was related to lower general cognitive abilities (r = -0.34, p < 0.02), lower verbal comprehension (r = -0.305, p < 0.05), and lower perceptual reasoning scores (r = -0.346, p = 0.02).

Conclusion: The children with type 1 diabetes had a lower serum BDNF level and poorer neurocognitive function than normal healthy children, especially those with GAD65-Ab positive diabetes. Poor glycemic control was correlated with worse cognitive performance.