title: Longitudinal trajectories of HbA1c and fasting plasma glucose levels during the development of type 2 diabetes: the Toranomon Hospital Health Management Center Study 7 (TOPICS 7).
abstract: OBJECTIVE
  To describe the trajectory of HbA(1c) and glucose concentrations before the diagnosis of diabetes.
  
  
  METHODS
  The study comprised 1,722 nondiabetic Japanese individuals aged 26-80 years. Fasting plasma glucose (FPG) and HbA(1c) were measured annually for a mean of 9.5 (SD 1.8) years.
  
  
  RESULTS
  Diabetes occurred in 193 individuals (FPG ≥ 7.0 mmol/L, self-reported clinician-diagnosed diabetes, or HbA(1c) ≥ 6.5%). Mean HbA(1c) values were >5.6% each year before diagnosis in diabetes cases. Mean HbA(1c) (5.69% [95% CI 5.50-5.88]) was higher in the 21 individuals who developed diabetes 10 years after the baseline examination than in nondiabetic individuals after 10 years (5.27% [5.25-5.28]). From 3 years to 1 year prediagnosis, HbA(1c) increased 0.09% (SE 0.01)/year, reaching 5.90% (5.84-5.96) 1 year prediagnosis. In the entire group, marked increases in HbA(1c) of 0.3% (SE 0.05%)/year and FPG of 0.63 (0.07) mmol/L/year predicted diabetes.
  
  
  CONCLUSIONS
  HbA(1c) trajectory increased sharply after gradual long-term increases in diabetic individuals.
authors.affiliation: Department of Internal Medicine, University of Tsukuba Institute of Clinical Medicine, Ibaraki, Japan.
authors.forename: Yoriko
authors.initials: Y
authors.lastname: Heianza
authors.forename: Yasuji
authors.initials: Y
authors.lastname: Arase
authors.forename: Kazuya
authors.initials: K
authors.lastname: Fujihara
authors.forename: Shiun Dong
authors.initials: SD
authors.lastname: Hsieh
authors.forename: Kazumi
authors.initials: K
authors.lastname: Saito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tsuji
authors.forename: Satoru
authors.initials: S
authors.lastname: Kodama
authors.forename: Naoya
authors.initials: N
authors.lastname: Yahagi
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Shimano
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Yamada
authors.forename: Shigeko
authors.initials: S
authors.lastname: Hara
authors.forename: Hirohito
authors.initials: H
authors.lastname: Sone
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001786:Blood Glucose / Q000378:metabolism*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000453:epidemiology / Q000378:metabolism*; D005215:Fasting / Q000097:blood*; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin