title: Cross-sectional and longitudinal relationships of body mass index with glycemic control in children and adolescents with type 1 diabetes mellitus.
abstract: OBJECTIVE
  Weight gain is an oft-cited outcome of improved glycemic control in adults with type 1 diabetes, though few studies have investigated this in youth. The purpose of this paper was to examine cross-sectional and longitudinal associations of body mass index (BMI, kg/m(2)) with glycemic control in youth with type 1 diabetes (n=340, 12.5 ± 1.7 year, 49% female, duration ≥ 1 year) participating in a 2-year multi-center intervention study targeting family diabetes management.
  
  
  METHODS
  BMI was calculated from height and weight measured at clinic visits. Glycohemoglobin (HbA1c) at each visit was assayed centrally. Cross-sectional associations of baseline BMI with glycemic control, and of change in BMI and HbA1c with baseline values, were examined. Longitudinal associations of time-varying BMI and HbA1c were examined using a multilevel linear mixed effects model controlling for time-varying time (months), insulin dose (units/kg/day), regimen, Tanner stage, and time invariant baseline diabetes duration, BMI, treatment group and sociodemographic characteristics.
  
  
  RESULTS
  Baseline HbA1c was unrelated to baseline BMI, but was related positively to subsequent BMI change (p=0.04) and inversely to HbA1c change (p=0.002). Baseline BMI was inversely related to BMI change (p=0.01) and unrelated to HbA1c change. In multilevel regression, BMI was related inversely to HbA1c (%) (β ± SE=-0.11 ± 0.02, p<0.001) and positively to insulin dose (0.23 ± 0.07, p=0.001). In the treatment group only, BMI was positively related to pump regimen (0.18 ± 0.08, p=0.02).
  
  
  CONCLUSIONS
  Increased insulin administered to improve glycemic control may contribute to increased BMI in youth with type 1 diabetes, indicating the importance of determining ways to minimize weight gain while optimizing glycemic control.
authors: Prevention Research Branch, Eunice Kennedy Shriver National Institute of Child Health and Human Development, United States. nanselt@mail.nih.gov
authors: T R
authors: TR
authors: Nansel
authors: L M
authors: LM
authors: Lipsky
authors: R J
authors: RJ
authors: Iannotti
mesh_terms: D000293:Adolescent; D016497:Adolescent Health Services; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D001835:Body Weight; D002648:Child; D002662:Child Health Services; D003430:Cross-Sectional Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications / Q000453:epidemiology*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000627:therapeutic use*; D008137:Longitudinal Studies; D008297:Male; D009765:Obesity / Q000097:blood / Q000453:epidemiology* / Q000517:prevention & control; D014481:United States / Q000453:epidemiology; D015430:Weight Gain / Q000187:drug effects
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin; C517652:hemoglobin A1c protein, human