title: A longitudinal investigation of cognitive function in children and adolescents with type 1 diabetes mellitus.
abstract: OBJECTIVE
  Cross-sectional studies find altered cognition in youth with type 1 diabetes mellitus (T1DM). However, few longitudinal studies have examined the trajectories of their cognitive performance over time. The aims of this study were to explore longitudinal change in cognitive function in youth with T1DM as compared with nondiabetic sibling controls, and how glycemic control and age of onset influence cognitive performance over time.
  
  
  METHODS
  We assessed crystallized intelligence, visual-spatial ability, delayed memory, and processing speed at 3 time points using the same cognitive tasks in youth with T1DM and sibling controls. Hierarchical linear modeling examined relationships between diabetes, hyperglycemia (HbA1c values), age of onset, and cognition over 5.5 y.
  
  
  RESULTS
  Youth with diabetes performed worse than controls on visual-spatial ability and memory tasks over time, and did not improve as much in processing speed. Greater hyperglycemia was associated with lower crystallized intelligence and slower processing speed but better memory across all time points. There was a stronger negative relationship between hyperglycemia and visual-spatial ability for youth with earlier compared with later onset diabetes. Importantly, within-person decreases in hyperglycemia between time points were associated with improved visual-spatial ability and faster processing speed.
  
  
  CONCLUSIONS
  On average, differences in cognitive function between youth with T1DM and nondiabetic relatives are maintained or increase during childhood and adolescence. Hyperglycemia and age of onset can have negative effects on the developmental trajectories of cognitive processes in youth with T1DM. However, treatments that lower hyperglycemia may lead to improved cognitive function in youth with T1DM.
authors.affiliation: Department of Psychology, Saint Louis University, Missouri.
authors.forename: Brenda A
authors.initials: BA
authors.lastname: Kirchhoff
authors.affiliation: Department of Psychology, Saint Louis University, Missouri.
authors.forename: Dustin K
authors.initials: DK
authors.lastname: Jundt
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Tasha
authors.initials: T
authors.lastname: Doty
authors.affiliation: Department of Psychiatry, Washington University School of Medicine, St. Louis, Missouri.|Department of Neurology, Washington University School of Medicine, St. Louis, Missouri.|Department of Radiology, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Tamara
authors.initials: T
authors.lastname: Hershey
mesh_terms: D000293:Adolescent; D017668:Age of Onset; D016022:Case-Control Studies; D002648:Child; D003071:Cognition / Q000502:physiology*; D003922:Diabetes Mellitus, Type 1 / Q000523:psychology*; D006801:Humans; D006943:Hyperglycemia / Q000523:psychology*; D008137:Longitudinal Studies
keywords: cognition; diabetes mellitus; hyperglycemia; memory; pediatrics; type 1