Table 1

Characteristics of NHANES participants (1999–2006) without self-reported diabetes, by A1C and fasting plasma glucose

A1C <6.5%A1C ≥6.5%
FPG <126 mg/dlFPG ≥126 mg/dlFPG <126 mg/dlFPG ≥126 mg/dl
n6,54114245162
Prevalence (95% CI)95.9 (95.3–96.5)1.8 (1.5–2.2)0.5 (0.4–0.7)1.8 (1.5–2.1)
Age (years)44.7 ± 0.4†60.0 ± 1.6*53.1 ± 2.757.2 ± 1.5
Women (%)52.936.339.838.7
Race/ethnicity
    Non-Hispanic white (%)76.2*81.964.959.5
    Non-Hispanic black (%)10.7†7.4‡25.914.9
    Hispanic (%)13.010.69.325.6
Current smoker (%)23.815.116.522.8
Systolic blood pressure (mmHg)121.3 ± 0.3137.6 ± 1.9130.0 ± 4.5132.3 ± 2.6
Diastolic blood pressure (mmHg)71.1 ± 0.372.0 ± 1.475.8 ± 3.771.2 ± 1.7
Hypertension (%)25.365.252.756.7
BMI (kg/m2)27.9 ± 0.1*31.2 ± 0.634.1 ± 2.532.7 ± 0.8
Waist circumference (cm)95.5 ± 0.3*107.5 ± 1.2112.9 ± 6.5110.1 ± 1.6
Total cholesterol (mg/dl)200.9 ± 0.8198.8 ± 4.8196.5 ± 6.7215.2 ± 5.7
HDL cholesterol (mg/dl)53.4 ± 0.349.1 ± 1.347.7 ± 3.744.3 ± 1.1
Triglycerides (mg/dl)§112 (78–164)147 (106–214)127 (88–151)178 (128–257)‡
Estimated glomerular filtration rate
    <60 ml/min per 1.73 m27.421.617.015.6
Microalbuminuria (%)7.024.214.729.6
Hb (g/dl)14.6 ± 0.115.0 ± 0.2†14.3 ± 0.215.1 ± 0.1†
Serum albumin (g/dl)4.29 ± 0.014.25 ± 0.044.17 ± 0.084.18 ± 0.03
Ferritin (ng/ml)§67 (31–136)†137 (77–253)122 (57–139)219 (96–293)*
Aspartate aminotransferase (units/l)24.9 ± 0.228.3 ± 1.830.0 ± 3.327.7 ± 1.8
Alanine aminotransferase (unites/l)25.6 ± 0.3†30.7 ± 2.036.2 ± 3.733.6 ± 2.6
C-reactive protein (mg/l)§1.9 (0.7–4.4)†2.2 (1.2–6.2)*4.2 (2.1–12.9)4.1 (2.5–9.0)
FPG (mg/dl)95.5 ± 0.3136.9 ± 1.1110.6 ± 2.2199.9 ± 7.7
A1C (%)5.26 ± 0.015.82 ± 0.056.92 ± 0.148.34 ± 0.19
  • §Data are means ± SE or percent, except variables denoted by §, which are medians (25th to 75th percentiles).

  • *P < 0.05;

  • P < 0.01;

  • P < 0.001 compared with individuals with A1C ≥6.5% and fasting plasma glucose (FPG) <126 mg/dl (after age adjustment).