Table 1.
Baseline characteristics of the study group. Values are represented as median ± interquartile range (IQR, 25–75th percentile). NA means not applicable due to non-statistically significant values from Kruskal–Wallis test. BMI: body mass index; WHR: waist-to-hip ratio; AUC: area under the curve; HbA1c: hemoglobin A1c; HOMA-IR: Homeostatic Model Assessment for Insulin Resistance; ISI: Insulin Sensitivity Index; UCP: urinary C-peptide; UCR: urinary creatinine; UCPCR: urinary C-peptide-to-creatinine ratio. HbA1c: hemoglobin A1c [20–42 mmol/mol]; fasting blood glucose (70–100 mg/dL); fasting blood C-peptide [0.78–1.89 ng/mL]; fasting blood insulin (3–25 mU/L); blood creatinine (female: 0.50–0.90 mg/dL, male: 0.70–1.20 mg/dL). Numbers in bold are considered statistically significant (p value < 0.05).
| Variables | All N = 447 |
Healthy N = 317 |
PreDM N = 87 |
T2DM N = 43 |
p-Value | Healthy vs. preDM (p-adj.) |
Healthy vs. T2DM (p-adj.) |
PreDM vs. T2DM (p-adj.) |
|---|---|---|---|---|---|---|---|---|
| Age (years) | 57 (51–63) |
56 (51–62) |
59 (53–66) |
61 (58–67) |
<0.001 | 0.021 | 0.002 | 0.728 |
| BMI (kg/m2) | 25.90 (23.67–29.05) |
24.84 (22.75–27.50) |
27.80 (25.60–30.80) |
30.80 (26.10–33.90) |
<0.001 | <0.001 | <0.001 | 0.111 |
|
Hip
circumference (cm) |
99 (92–106) |
96 (90–103) |
103 (95–109) |
108 (102–118) |
<0.001 | <0.001 | <0.001 | 0.007 |
|
Waist
circumference (cm) |
90 (80–100) |
87 (77–95) |
96 (90–105) |
107 (97–116) |
<0.001 | <0.001 | <0.001 | 0.035 |
| WHR | 0.92 (0.86–0.97) |
0.90 (0.84–0.95) |
0.96 (0.90–1.01) |
0.98 (0.92–1.02) |
<0.001 | <0.001 | <0.001 | 0.849 |
| Weight (kg) | 77 (66–86) |
72 (63–83.50) |
82 (74–88) |
88 (80–103) |
<0.001 | <0.001 | <0.001 | 0.124 |
| Height (cm) | 170 (164–178) |
169 (164–176.50) |
173 (165–179) |
172 (165–178) |
0.138 | NA | NA | NA |
| Total lean mass (kg) | 47.70 (40.75–57.50) |
44.85 (39.85–56.27) |
52.92 (43.77–57.93) |
56.78 (45.29–62.98) |
<0.001 | <0.001 | <0.001 | 0.504 |
| Total fat mass (kg) | 24.67 (19.48–31.60) |
23.23 (18.32–28.88) |
28.26 (22.15–36.25) |
31.33 (27.07–37.66) |
<0.001 | <0.001 | <0.001 | 0.190 |
| Fasting blood glucose (mg/dL) | 91 (86–100) |
88 (84–93) |
104 (100–108) |
140 (123–164) |
<0.001 | <0.001 | <0.001 | 0.029 |
| AUC glucose | 14,265 (12,180–17,805) |
13,095 (11,610–15,008) |
18,795 (16,815–20,730) |
28,110 (24,660–34,470) |
<0.001 | <0.001 | <0.001 | 0.001 |
| HbA1c (mmol/mol) | 37 (35–39) |
36 (34–38) |
39 (37–42) |
52 (44–59) |
<0.001 | <0.001 | <0.001 | <0.001 |
| Fasting blood C-peptide (ng/mL) | 1.34 (1.02–1.98) |
1.19 (0.93–1.58) |
1.98 (1.44–2.58) |
2.55 (1.77–3.35) |
<0.001 | <0.001 | <0.001 | 0.142 |
|
1-h stimulated blood C-peptide
(ng/mL) |
6.38 (5.00–8.46) |
6.15 (4.59–7.98) |
7.82 (6.20–10.34) |
6.01 (4.54–8.15) |
<0.001 | <0.001 | 1.000 | <0.001 |
| 2-h stimulated blood C-peptide (ng/mL) | 5.56 (3.90–8.01) |
4.77 (3.59–6.56) |
7.94 (5.74–11.07) |
8.14 (6.09–9.75) |
<0.001 | <0.001 | <0.001 | 1.000 |
| AUC C-peptide | 621 (477–788) |
576 (456–721) |
787 (620–962) |
686 (529–875) |
<0.001 | <0.001 | 0.020 | 0.114 |
| Fasting blood insulin (mU/L) | 9.20 (6.10–13.50) |
7.90 (5.00–11.35) |
11.90 (9.20–19.00) |
16.10 (10.10–22.70) |
<0.001 | <0.001 | <0.001 | 0.979 |
| AUC insulin | 5624 (3503–9272) |
4968 (3303–8062) |
7872 (4587–14,186) |
6275 (3962–9389) |
<0.001 | <0.001 | 0.215 | 0.637 |
| HOMA-IR | 2.11 (1.35–3.32) |
1.72 (1.10–2.50) |
3.09 (2.28–4.81) |
5.07 (3.60–9.22) |
<0.001 | <0.001 | <0.001 | 0.047 |
| HOMA-beta (%) | 110.77 (76.91–161.05) |
117 (82.87–163.39) |
109.13 (84.65–178.05) |
75.27 (40.91–115.41) |
<0.001 | 1.000 | 0.001 | 0.002 |
| ISI Stumvoll | 0.09 (0.07–0.11) |
0.10 (0.08–0.11) |
0.08 (0.01–0.09) |
0.06 (0.04–0.09) |
<0.001 | <0.001 | <0.001 | 0.809 |
| ISI Cederholm | 50.78 (35.91–66.21) |
57.08 (46.17–73.11) |
34.87 (25.27–47.31) |
20.28 (15.58–26.81) |
<0.001 | <0.001 | <0.001 | 0.000 |
| Matsuda index | 5.06 (3.16–8.27) |
6.17 (4.20–9.38) |
3.09 (1.72–4.88) |
2.18 (1.28–3.35) |
<0.001 | <0.001 | <0.001 | 0.056 |
| Blood creatinine (mg/dL) | 0.86 (0.76–0.98) |
0.84 (0.75–0.96) |
0.93 (0.83–1.05) |
0.86 (0.76–0.96) |
<0.001 | <0.001 | 1.000 | 0.133 |
| UCP (nmol/L) | 5.43 (2.98–9.73) |
4.64 (2.60–8.00) |
8.24 (4.73–11.85) |
10.83 (8.31–15.43) |
<0.001 | <0.001 | <0.001 | 0.071 |
| UCR (mmol/L) | 11.23 (6.72–15.38) |
10.96 (6.10–15.38) |
11.85 (7.69–16.00) |
11.93 (8.49–16.09) |
0.287 | NA | NA | NA |
| UCPCR (nmol/mmol) | 0.59 (0.33–0.93) |
0.49 (0.30–0.81) |
0.76 (0.46–1.10) |
0.92 (0.59–1.80) |
<0.001 | <0.001 | <0.001 | 0.269 |