Absence of Adverse Effects of Severe Hypoglycemia on Cognitive Function in School-Aged Children With Diabetes Over 18 Months
- Tim Wysocki, PHD1,
- Michael A. Harris, PHD2,
- Nelly Mauras, MD3,
- Larry Fox, MD3,
- Alexandra Taylor, MA1,
- S. Craig Jackson, BS2 and
- Neil H. White, MD, CDE24
- 1Division of Psychology and Psychiatry, Nemours Children’s Clinic, Jacksonville, Florida
- 3Division of Pediatric Endocrinology and Metabolism, School of Medicine, Washington University, St. Louis, Missouri
- 2Division of Endocrinology and Metabolism, Nemours Children’s Clinic, Jacksonville, Florida
- 4St. Louis Children’s Hospital, St. Louis, Missouri
OBJECTIVE—Some children with type 1 diabetes may be at risk of cognitive impairments, but mechanisms of this effect have not been confirmed. The objective of this study was to determine whether severe hypoglycemia (SH) in children with type 1 diabetes is associated with cognitive decline over 18 months.
RESEARCH DESIGN AND METHODS—A sample of 142 6- to 15-year-old children with type 1 diabetes (mean age 11.6 ± 2.7 years) enrolled in a trial of intensive therapy (IT) or usual care (UC) were tested with the Das-Naglieri Cognitive Assessment System at baseline and after 9 and 18 months. Episodes of SH were recorded by parents and reported promptly for verification by study nurses. HbA1c was measured quarterly.
RESULTS—Over 18 months, 58 of 142 patients (41%) experienced 111 SH episodes, with a RR of SH of 1.12 for IT over UC. Neither occurrence nor frequency of SH was associated with decline in full-scale intelligence quotient (IQ), standard scores for planning, attention, simultaneous processing, or successive processing, or scaled scores on any of eight subtests. The same findings emerged when only patients who had experienced hypoglycemic seizures or coma were included in the SH group for analyses. These effects persisted when the child’s age, sex, type 1 diabetes duration, and age at diagnosis were controlled statistically. HbA1c during the trial was not associated with cognitive changes.
CONCLUSIONS—SH did not induce adverse changes in the measures of cognitive function administered to 6- to 15-year-old children with type 1 diabetes in this study. Although SH should be avoided in all children with diabetes, these episodes did not have adverse effects on cognition in this age-group over 18 months.
- CAS, cognitive assessment system
- DCCT, Diabetes Control and Complications Trial
- IQ, intelligence quotient
- IT, intensive therapy
- SH, severe hypoglycemia
- UC, usual care
Address correspondence and reprint requests to Tim Wysocki, PhD, Division of Psychology and Psychiatry, Nemours Children’s Clinic, 807 Children’s Way, Jacksonville, FL 32207. E-mail:.
Received for publication 1 October 2002 and accepted in revised form 30 December 2002.
A table elsewhere in this issue shows conventional and Système International (SI) units and conversion factors for many substances.
- DIABETES CARE