Table 1.
Baseline characteristics of the study population
| Characteristics | Incident type 2 diabetes | Incident (pre)diabetes | ||||
|---|---|---|---|---|---|---|
| Non-casesan = 660 | Casesbn = 123 | p valuee | Non-casescn = 446 | Casesdn = 255 | p valuee | |
| Male (%) | 47.3 | 56.1 | 0.089 | 43.7 | 57.6 | 0.001 |
| Characteristics at baseline | ||||||
| Age (years) | 57.4 ± 9.4 | 63.4 ± 8.6 | <0.001 | 55.8 ± 9.1 | 59.9 ± 9.3 | <0.001 |
| Waist circumference (cm) | 92.4 ± 13.8 | 102.2 ± 11.9 | <0.001 | 90.0 ± 12.4 | 97.5 ± 11.0 | <0.001 |
| Height (cm) | 169.0 ± 9.4 | 167.9 ± 9.2 | 0.377 | 169.0 ± 9.5 | 168.8 ± 9.5 | 0.976 |
| Physically inactive (%) | 35.5 | 51.2 | 0.001 | 33.6 | 41.6 | 0.044 |
| Smoking (%) | 0.035 | 0.880 | ||||
| Never | 45.0 | 55.3 | 45.1 | 45.1 | ||
| Former | 39.2 | 36.6 | 39.0 | 37.6 | ||
| Current | 15.8 | 8.1 | 15.9 | 17.3 | ||
| Actual hypertension (%) | 34.7 | 57.7 | <0.001 | 26.9 | 47.1 | <0.001 |
| Parental history of diabetes (%) | 0.010 | <0.001 | ||||
| No | 61.4 | 48.8 | 67.3 | 46.7 | ||
| Unknown | 15.0 | 20.3 | 11.7 | 24.3 | ||
| One parent | 21.4 | 24.4 | 19.5 | 25.1 | ||
| Both parents | 2.3 | 6.5 | 1.6 | 3.9 | ||
| Sibling history of diabetes (%) | 6.2 | 15.4 | 0.001 | 4.3 | 8.6 | 0.028 |
| Triglyceride level (mmol/l)f | 1.2 (0.8, 1.6) | 1.6 (1.2, 2.2) | <0.001 | 1.1 (0.8, 1.5) | 1.3 (0.9, 1.9) | <0.001 |
| Total chol./HDL-cholesterol ratiof | 3.9 (3.2, 4.6) | 4.4 (3.8, 5.4) | <0.001 | 3.7 (3.1, 4.5) | 4.2 (3.5, 4.9) | <0.001 |
| HbA1c (%) | 5.4 ± 0.3 | 5.8 ± 0.3 | <0.001 | 5.3 ± 0.3 | 5.5 ± 0.3 | <0.001 |
| HbA1c (mmol/mol) | 35.6 ± 3.4 | 39.8 ± 3.6 | <0.001 | 34.9 ± 3.2 | 37.0 ± 3.2 | <0.001 |
| Fasting glucosef,g (mmol/l) | 5.2 (4.9, 5.5) | 5.8 (5.4, 6.3) | <0.001 | 5.1 (4.8, 5.3) | 5.4 (5.2, 5.7) | <0.001 |
| 2-h-glucosef,g (mmol/l) | 5.8 (4.9, 6.9) | 8.3 (7.0, 9.2) | <0.001 | 5.4 (4.7, 6.3) | 6.3 (5.5, 7.0) | <0.001 |
| Fasting insulinf,g (pmol/l) | 49.8 (36.6, 66.0) | 72.0 (53.4, 123.0) | <0.001 | 46.2 (34.2, 60.0) | 60.0 (44.4, 78.0) | <0.001 |
| HOMA-IRf,g | 1.9 (1.4, 2.7) | 3.1 (2.3, 5.2) | <0.001 | 1.7 (1.3, 2.3) | 2.4 (1.8, 3.2) | <0.001 |
| Characteristics at follow-up | ||||||
| Fasting glucosef,g (mmol/l) | 5.4 (5.1, 5.8) | 6.8 (6.0, 7.3) | <0.001 | 5.3 (5.0, 5.5) | 6.0 (5.6, 6.3) | <0.001 |
| 2-h-glucosef,g (mmol/l) | 5.9 (5.0, 7.3) | 11.8 (10.3, 13.0) | <0.001 | 5.5 (4.7, 6.2) | 8.2 (7.3, 9.2) | <0.001 |
| Fasting insulinf,g (pmol/l) | 55.4 (37.8, 81.0) | 96.0 (66.0, 132.0) | <0.001 | 49.2 (35.3, 68.8) | 74.9 (54.2, 104.5) | <0.001 |
| HOMA-IRf,g | 2.2 (1.5, 3.3) | 4.8 (3.0, 6.9) | <0.001 | 1.9 (1.3, 2.8) | 3.4 (2.3, 4.7) | <0.001 |
Percentages are given for categorical variables, arithmetic means ± SDs for approximately normally distributed, and median (25th; 75th percentile) for skewed continuous variables
aNondiabetic (fasting glucose < 7.0 mmol/l and 2-h-glucose ≤ 11.1 mmol/l) at baseline and follow-up
bNondiabetic at baseline and known clinically diagnosed (n = 56) or newly OGTT diagnosed (n = 67) type 2 diabetes (fasting glucose ≥ 7.0 mmol/l and/or 2-h-glucose ≥ 11.1 mmol/l) at follow-up
cNormoglycemia (fasting glucose < 6.1 mmol/l and 2-h-glucose < 7.8 mmol/l) at baseline and follow-up
dNormoglycemia at baseline and prediabetes (n = 223) or known (n = 16) or newly diagnosed (n = 16) type 2 diabetes at follow-up (fasting glucose ≥ 6.1 mmol/l and/or 2-h-glucose ≥ 7.8 mmol/l)
eFor differences between groups: Kruskal–Wallis test for continuous variables; χ2 test for categorical variables
fSkewed, continuous variables
gDescriptive statistics for the continuous type 2 diabetes related traits are only given for the study participants who were included in the linear regression analyses of these traits; number of non-cases/cases incident type 2 diabetes: n = 660/88 for fasting glucose, n = 660/64 for 2-h-glucose, n = 657/87 for fasting insulin and HOMA-IR; non-cases/cases (pre)diabetes: n = 446/247 for fasting glucose, n = 446/239 for 2-h-glucose, n = 445/246 for fasting insulin and HOMA-IR