title: Type 1 diabetic drivers with and without a history of recurrent hypoglycemia-related driving mishaps: physiological and performance differences during euglycemia and the induction of hypoglycemia.
abstract: OBJECTIVE
  Collisions are more common among drivers with type 1 diabetes than among their nondiabetic spouses. This increased risk appears to be attributable to a subgroup of drivers with type 1 diabetes. The hypothesis tested is that this vulnerable subgroup is more at risk for hypoglycemia and its disruptive effects on driving.
  
  
  METHODS
  Thirty-eight drivers with type 1 diabetes, 16 with (+history) and 22 without (-history) a recent history of recurrent hypoglycemia-related driving mishaps, drove a virtual reality driving simulator and watched a videotape of someone driving a simulator for 30-min periods. Driving and video testing occurred in a double-blind, randomized, crossover manner during euglycemia (5.5 mmol/l) and progressive hypoglycemia (3.9-2.5 mmol/l). Examiners were blind to which subjects were +/-history, whereas subjects were blind to their blood glucose levels and targets.
  
  
  RESULTS
  During euglycemia, +history participants reported more autonomic and neuroglycopenic symptoms (P≤0.01) and tended to require more dextrose infusion to maintain euglycemia with the same insulin infusion (P<0.09). During progressive hypoglycemia, these subjects demonstrated less epinephrine release (P=0.02) and greater driving impairments (P=0.03).
  
  
  CONCLUSIONS
  Findings support the speculation that there is a subgroup of type 1 diabetic drivers more vulnerable to experiencing hypoglycemia-related driving mishaps. This increased vulnerability may be due to more symptom "noise" (more symptoms during euglycemia), making it harder to detect hypoglycemia while driving; possibly greater carbohydrate utilization, rendering them more vulnerable to experiencing hypoglycemia; less hormonal counterregulation, leading to more profound hypoglycemia; and more neuroglycopenia, rendering them more vulnerable to impaired driving.
authors.affiliation: Department of Psychiatry and Neurobehavioral Sciences, University of Virginia Health SciencesCenter, Charlottesville, Virginia, USA. djc4f@virginia.edu
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Cox
authors.forename: Boris P
authors.initials: BP
authors.lastname: Kovatchev
authors.forename: Stacey M
authors.initials: SM
authors.lastname: Anderson
authors.forename: William L
authors.initials: WL
authors.lastname: Clarke
authors.forename: Linda A
authors.initials: LA
authors.lastname: Gonder-Frederick
mesh_terms: D000328:Adult; D000368:Aged; D001334:Automobile Driving; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy / Q000503:physiopathology*; D004837:Epinephrine / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000627:therapeutic use; D006801:Humans; D007003:Hypoglycemia / Q000188:drug therapy / Q000378:metabolism / Q000503:physiopathology*; D007328:Insulin / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D055815:Young Adult
chemical_list: D007328:Insulin; D005947:Glucose; D004837:Epinephrine