title: Association between Inflammation and Biological Variation in Hemoglobin A1c in U.S. Nondiabetic Adults.
abstract: BACKGROUND
  Inflammation is associated with higher glycated hemoglobin (HbA1c) levels. Whether the relationship is independent of blood glucose concentration remains unclear.
  
  
  OBJECTIVE
  The hemoglobin glycation index (HGI) was used to test the hypothesis that interindividual variation in HbA1c is associated with inflammation.
  
  
  METHODS
  This study used nondiabetic adults from the National Health and Nutrition Examination Survey (1999-2008).
  
  
  METHODS
  A subsample of participants was used to estimate the linear regression relationship between HbA1c and fasting plasma glucose (FPG). Predicted HbA1c were calculated for 7323 nondiabetic participants by inserting FPG into the equation, HbA1c = 0.017 × FPG (mg/dL) + 3.7. HGI was calculated as the difference between the observed and predicted HbA1c and the population was divided into low, moderate, and high HGI subgroups. Polymorphonuclear leukocytes (PMNL), monocytes, and C-reactive protein (CRP) were used as biomarkers of inflammation.
  
  
  RESULTS
  Mean HbA1c, CRP, monocyte, and PMNL levels, but not FPG, progressively increased in the low, moderate, and high HGI subgroups. There were disproportionately more Blacks than whites in the high HGI subgroup. CRP (ß, 0.009; 95% confidence interval [CI], 0.0001-0.017), PMNL (ß, 0.036; 95% CI, 0.010-0.062), and monocyte count (ß, 0.072; 95% CI, 0.041-0.104) were each independent predictors of HGI after adjustment for age, sex, race, triglycerides, hemoglobin level, mean corpuscular volume, red cell distribution width, and obesity status.
  
  
  CONCLUSIONS
  HGI reflects the effects of inflammation on HbA1c in a nondiabetic population of U.S. adults and may be a marker of risk associated with inflammation independent of FPG, race, and obesity.
authors: Department of Medicine (S.L., V.A.F.), Tulane University Health Sciences Center, New Orleans, Louisiana 70112; Department of Global Health System and Development (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112; Department of Pediatrics (J.M.H.), Louisiana State University Health Sciences Center and Children's Hospital Research Institute for Children, New Orleans, Louisiana 70118; Research Division of Biostatistics and Study Methodology (R.J.M.), Children's National Medical Center, Washington, District of Columbia 20010; Department of Epidemiology (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112.
authors: Shuqian
authors: S
authors: Liu
authors: Department of Medicine (S.L., V.A.F.), Tulane University Health Sciences Center, New Orleans, Louisiana 70112; Department of Global Health System and Development (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112; Department of Pediatrics (J.M.H.), Louisiana State University Health Sciences Center and Children's Hospital Research Institute for Children, New Orleans, Louisiana 70118; Research Division of Biostatistics and Study Methodology (R.J.M.), Children's National Medical Center, Washington, District of Columbia 20010; Department of Epidemiology (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112.
authors: James M
authors: JM
authors: Hempe
authors: Department of Medicine (S.L., V.A.F.), Tulane University Health Sciences Center, New Orleans, Louisiana 70112; Department of Global Health System and Development (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112; Department of Pediatrics (J.M.H.), Louisiana State University Health Sciences Center and Children's Hospital Research Institute for Children, New Orleans, Louisiana 70118; Research Division of Biostatistics and Study Methodology (R.J.M.), Children's National Medical Center, Washington, District of Columbia 20010; Department of Epidemiology (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112.
authors: Robert J
authors: RJ
authors: McCarter
authors: Department of Medicine (S.L., V.A.F.), Tulane University Health Sciences Center, New Orleans, Louisiana 70112; Department of Global Health System and Development (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112; Department of Pediatrics (J.M.H.), Louisiana State University Health Sciences Center and Children's Hospital Research Institute for Children, New Orleans, Louisiana 70118; Research Division of Biostatistics and Study Methodology (R.J.M.), Children's National Medical Center, Washington, District of Columbia 20010; Department of Epidemiology (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112.
authors: Shengxu
authors: S
authors: Li
authors: Department of Medicine (S.L., V.A.F.), Tulane University Health Sciences Center, New Orleans, Louisiana 70112; Department of Global Health System and Development (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112; Department of Pediatrics (J.M.H.), Louisiana State University Health Sciences Center and Children's Hospital Research Institute for Children, New Orleans, Louisiana 70118; Research Division of Biostatistics and Study Methodology (R.J.M.), Children's National Medical Center, Washington, District of Columbia 20010; Department of Epidemiology (S.L.), School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112.
authors: Vivian A
authors: VA
authors: Fonseca
mesh_terms: D000328:Adult; D001772:Blood Cell Count; D001786:Blood Glucose / Q000378:metabolism; D002097:C-Reactive Protein / Q000378:metabolism; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006031:Glycosylation; D006305:Health Status Indicators; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D007249:Inflammation / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology; D009749:Nutrition Surveys; D014481:United States / Q000453:epidemiology
chemical_list: D001786:Blood Glucose; D002097:C-Reactive Protein; D006442:Glycated Hemoglobin; D006454:Hemoglobins; C517652:hemoglobin A1c protein, human