title: Factors associated with nocturnal hypoglycemia in at-risk adolescents and young adults with type 1 diabetes.
abstract: BACKGROUND
  Hypoglycemia remains an impediment to good glycemic control, with nocturnal hypoglycemia being particularly dangerous. Information on major contributors to nocturnal hypoglycemia remains critical for understanding and mitigating risk.
  
  
  METHODS
  Continuous glucose monitoring (CGM) data for 855 nights were studied, generated by 45 subjects 15-45 years of age with hemoglobin A1c (HbA1c) levels of ≤8.0% who participated in a larger randomized study. Factors assessed for potential association with nocturnal hypoglycemia (CGM measurement of <60 mg/dL for ≥30 min) included bedtime blood glucose (BG), exercise intensity, bedtime snack, insulin on board, day of the week, previous daytime hypoglycemia, age, gender, HbA1c level, diabetes duration, daily basal insulin, and daily insulin dose.
  
  
  RESULTS
  Hypoglycemia occurred during 221 of 885 (25%) nights and was more frequent with younger age (P<0.001), lower HbA1c levels (P=0.006), medium/high-intensity exercise during the preceding day (P=0.003), and the occurrence of antecedent daytime hypoglycemia (P=0.001). There was a trend for lower bedtime BG levels to be associated with more frequent nocturnal hypoglycemia (P=0.10). Bedtime snack, before bedtime insulin bolus, weekend versus weekday, gender, and daily basal and bolus insulin were not associated with nocturnal hypoglycemia.
  
  
  CONCLUSIONS
  Awareness that HbA1c level, exercise, bedtime BG level, and daytime hypoglycemia are all modifiable factors associated with nocturnal hypoglycemia may help patients and providers decrease the risk of hypoglycemia at night. Risk for nocturnal hypoglycemia increased in a linear fashion across the range of variables, with no clear-cut thresholds to guide clinicians or patients for any particular night.
authors.affiliation: 1 Stanford University , Stanford, California.
authors.forename: Darrell M
authors.initials: DM
authors.lastname: Wilson
authors.forename: Peter M
authors.initials: PM
authors.lastname: Calhoun
authors.forename: David M
authors.initials: DM
authors.lastname: Maahs
authors.forename: H Peter
authors.initials: HP
authors.lastname: Chase
authors.forename: Laurel
authors.initials: L
authors.lastname: Messer
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Buckingham
authors.forename: Tandy
authors.initials: T
authors.lastname: Aye
authors.forename: Paula K
authors.initials: PK
authors.lastname: Clinton
authors.forename: Irene
authors.initials: I
authors.lastname: Hramiak
authors.forename: Craig
authors.initials: C
authors.lastname: Kollman
authors.forename: Roy W
authors.initials: RW
authors.lastname: Beck
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D001786:Blood Glucose / Q000032:analysis; D015190:Blood Glucose Self-Monitoring; D002940:Circadian Rhythm; D003922:Diabetes Mellitus, Type 1 / Q000097:blood* / Q000150:complications / Q000188:drug therapy; D015444:Exercise; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D006801:Humans; D007003:Hypoglycemia / Q000097:blood* / Q000188:drug therapy / Q000209:etiology / Q000517:prevention & control; D007004:Hypoglycemic Agents / Q000008:administration & dosage; D007328:Insulin / Q000008:administration & dosage; D007332:Insulin Infusion Systems; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D012737:Sex Factors; D062410:Snacks; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; C517652:hemoglobin A1c protein, human