title: Associations of HbA1c and fasting plasma glucose with incident diabetes: Implications for pre-diabetes thresholds in a Japanese population.
abstract: This study assessed pre-diabetes (pre-DM) cutoffs for HbA1c and fasting plasma glucose (FPG) that were associated with an increased risk of incident DM.
  
  
  
  We evaluated 2267 non-diabetic Japanese health-check examinees (HbA1c: <6.5% [<48mmol/mol] and FPG: <7.0mmol/L) who were 30-79 years old and were followed-up for 5 years. Incident DM was defined as HbA1c of ≥6.5% (≥48mmol/mol), FPG of ≥7.0mmol/L, or physician-diagnosed DM.
  
  
  
  During 11047 person-years, we identified 99 incident DM cases (4.3%). The incidence of DM increased with increasing baseline HbA1c or FPG levels, and the change points (95% confidence intervals) were 5.7% (5.6-5.7%; 39mmol/mol [38-39mmol/mol]) for HbA1c and 5.5mmol/L (5.5-5.6mmol/L) for FPG. The adjusted hazard ratios (HRs) for incident DM per one standard deviation-increase in HbA1c and FPG were 5.5 (4.4-6.8) and 4.0 (3.2-4.8), respectively. The adjusted HRs for incident DM were significantly higher at HbA1c of 5.7-6.4% (39-46mmol/mol) or FPG of 5.5-6.9mmol/L, compared to HbA1c of <5.7% (<39mmol/mol) or FPG of <5.5mmol/L.
  
  
  
  The lower cut-offs for pre-DM may be 5.7% (39mmol/mol) for HbA1c and 5.5mmol/L for FPG in this Japanese population.
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan. Electronic address: nakagami.dmc@twmu.ac.jp.
authors: Tomoko
authors: T
authors: Nakagami
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Yuki
authors: Y
authors: Tanaka
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Junko
authors: J
authors: Oya
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Moritoshi
authors: M
authors: Kurita
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Chisato
authors: C
authors: Isago
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Yukiko
authors: Y
authors: Hasegawa
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Arata
authors: A
authors: Ito
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Naoki
authors: N
authors: Hirota
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Reika
authors: R
authors: Tsuzura
authors: Department of Medicine III, Diabetes Center, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors: Yasuko
authors: Y
authors: Uchigata
mesh_terms: D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism*; D005215:Fasting; D005260:Female; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011236:Prediabetic State / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology*; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D006442:Glycated Hemoglobin; C517652:hemoglobin A1c protein, human
keywords: Diabetes; Fasting plasma glucose; HbA1c; Incidence; Pre-diabetes