Type 1 diabetes appears to affect cognitive development in young children, with side effects lasting over time and strong associations with long- and short-term hyperglycemia, a new longitudinal study shows.
“”[The results show] The brain is a target of diabetes complications, even in young children, “write the authors of the study, published online February 10 in Diabetes Care.
Previous studies by this and other researchers have shown that children with type 1 diabetes have significant short-term differences in brain volume and growth. And so the current authors have expanded the work with the Diabetes Research in Children Network (DirecNet), a multicenter consortium funded by the National Institutes of Health, and are the longest longitudinal study of its kind.
These new data “help lower glycemic goals in children” and state that the acceptance of higher than average blood sugar as an appropriate metabolic control in very young children “needs to be re-examined”.
Early Effects of Diabetes on IQ Are “Detectable and Significant”
For the current study, DirecNet researchers included 144 children with type 1 diabetes and an average age of 7 years, which is the age of 72 control children without diabetes. People with diabetes had an average disease duration of 2.4 years at the start of the study.
All participants had structural MRI and age-appropriate cognitive tests up to four times over approximately 6.4 years, quarterly A1c, and continuous glucose monitoring.
The comparisons showed that those with type 1 diabetes had lower IQ and lower verbal IQ during the study period at baseline and after 8, 10 and 12 years, with no neurocognitive measures widening or narrowing significantly over the course of the study .
The estimated group differences in full-scale cognitive IQ scores at the four time points in the type 1 diabetes group were -4.15, -3.81, -3.46 and -3.11, respectively (P <0.05) .
The results show that “the early effects of diabetes are demonstrable and significant,” the authors write.
In addition, in the diabetes group aged 6 to 12 years, significantly lower volumes were observed in all three major structural brain measurements of whole brain, gray and white matter, with differences increasing over time.
In particular, the differences in total brain volume increased after 6, 8, 10 and 12 years from -15,410 to -21,159, -25,548 and -28,577 mm3 x 103 (P <0.05).
“This is a potentially important finding that suggests cumulative effects on the developing central nervous system,” the authors write.
About half of the sensor glucose measurements at all time points in patients with diabetes were above target (> 180 mg / dL), and most importantly, a highly significant relationship was observed between the cognitive measurements and the short- and long-term metrics of hyperglycemia.
A negative correlation was also observed between the total volume and the volume of gray matter in glycemic measurements, but particularly in the measurement of the A1c-AUC> 6%.
No similar associations were observed with hypoglycaemia.
“Given that approximately 50% of sensor glucose readings were above 180 mg / dL in children with diabetes during the mean 6.4 year follow-up, these associations of hyperglycemia and observed changes in brain structure and cognition are both worrying and supportive This chronically elevated glucose is indeed harmful to the developing brain, “the authors write.
Cognitive scores in the normal range, but differences a problem
As reported by Medscape Medical News, previous research by the DirecNet team has linked type 1 diabetes and poor metabolic control in adolescents to lower IQs and other deficits such as managerial functioning. Long-term results, however, have not been conclusive.
The authors note that in the current study, although children with diabetes still functioned well and had IQ scores in the normal range, the group differences were important, averaging almost 4 IQ points.
“While this may not readily affect academic performance or relationship behavior in this particular highly functional cohort, it is within the range seen with other disorders affecting the brain in children,” they write.
“Persistent volumetric differences across all four time points, as well as detectable cognitive deficits compared to controls, suggest that the effects of diabetes on the brain begin early in the disease,” they add.
Regarding recommendations for future studies, one of the authors, Dr. Allan Reiss, a professor at Stanford University School of Medicine in California, explained the need to focus on two key areas.
“The first is to study these and other populations of people with type 1 diabetes into young adulthood to see if and how brain and cognitive problems affect long-term educational and professional outcomes,” he said in a press release.
“The second is to see if tighter early control of blood sugar can stop or even reverse the brain and cognitive effects that we observed in this study,” he concluded.
Diabetes treatment. Published online 10 February 2021. Executive summary
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