title: Glycemic control and variability in association with body mass index and body composition over 18months in youth with type 1 diabetes.
abstract: OBJECTIVE
  The impact of adiposity on glycemic control in type 1 diabetes patients has important implications for preventing complications. This study examined associations of glycemic outcomes with body mass index (BMI, kg/m(2)) and body composition in youth with type 1 diabetes.
  
  
  METHODS
  This is a secondary analysis of an 18-month randomized controlled dietary intervention trial (N=136, baseline age=12.3±2.5y, HbA1c=8.1±1.0% (65±11mmol/mol)). Measured height and weight every 3months were abstracted from medical records. Body composition was assessed by dual energy X-ray absorptiometry (DXA) at baseline, 12 and 18months. Glycated hemoglobin (HbA1c) and glycemic variability assessed by masked 3-day continuous blood glucose monitoring (CGM) were obtained every 3months. 1,5-Anhydroglucitol (1,5-AG) was assessed every 6months. Adjusted random effects models for repeated measures estimated associations of time-varying BMI and body composition with time-varying glycemic outcomes.
  
  
  RESULTS
  There was no treatment effect on glycemic outcomes. HbA1c was not associated with BMI or body composition indicators. 1,5-AG was inversely associated with BMI and adiposity indicators (%fat, trunk fat mass and trunk %fat), adjusting for developmental covariates. Adiposity indicators were positively associated with %glucose >180mg/dL and >126mg/dL when adjusting for developmental covariates, and %glucose >126mg/dL when additionally adjusting for diabetes-related covariates. Fewer consistent relationships were observed for 3-day mean glucose and %glucose <70.2mg/dL. BMI and body composition variables were not associated with standard deviation of glycemic values or mean amplitude of glycemic excursions.
  
  
  CONCLUSIONS
  The role of greater BMI and adiposity in diabetes management in youth with type 1 diabetes may relate specifically to increased hyperglycemic excursions.
authors.affiliation: Health Behavior Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, North Bethesda, MD, United States. Electronic address: lipskylm@mail.nih.gov.
authors.forename: Leah M
authors.initials: LM
authors.lastname: Lipsky
authors.affiliation: Health Behavior Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, North Bethesda, MD, United States.
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gee
authors.affiliation: Biostatistics and Bioinformatics Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, North Bethesda, MD, United States.
authors.forename: Aiyi
authors.initials: A
authors.lastname: Liu
authors.affiliation: Health Behavior Branch, Division of Intramural Population Health Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, North Bethesda, MD, United States.
authors.forename: Tonja R
authors.initials: TR
authors.lastname: Nansel
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity; D000293:Adolescent; D001786:Blood Glucose / Q000032:analysis*; D001823:Body Composition; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications* / Q000503:physiopathology; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D007003:Hypoglycemia / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D009765:Obesity / Q000150:complications*
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin
keywords: 1,5-Anhydroglucitol; Adolescent; Body composition; Body mass index; Diabetes mellitus, type 1; Hemoglobin A glycosylated