Table 1. Basic characteristics of the study group by categories of glucose regulation: The KORA FF4 study a.
| Normal glucose tolerance | Prediabetes | Undiagnosed diabetes | Previously known diabetes | |
|---|---|---|---|---|
| N | 1,086 | 773 | 94 | 233 |
| Age (years) | 55.7 ± 11.3 | 62.8 ± 11.5 | 68.4 ± 10.6 | 69.7 ± 10.0 |
| Sex (male) (%) | 37.9 | 60.5 | 58.5 | 57.5 |
| BMI (kg/m2) | 26.1 ± 7.4 | 28.9 ± 4.7 | 31.3 ± 5.5 | 31.0 ± 5.2 |
| Waist circumference (cm) | 91.0 ± 12.7 | 101.0 ± 12.6 | 107.0 ± 13.5 | 107.3 ± 12.6 |
| HDL cholesterol (mmol/l) | 1.81 ± 0.49 | 1.60 ± 0.45 | 1.46 ± 0.42 | 1.51 ± 0.43 |
| LDL cholesterol (mmol/l) | 3.45 ± 0.88 | 3.61 ± 0.91 | 3.63 ± 1.04 | 3.13 ± 0.87 |
| Triglycerides (mmol/l) | 1.03 (0.77; 1.38) | 1.33 (0.98; 1.82) | 1.62 (1.25; 2.46) | 1.43 (1.09; 2.08) |
| Hypertension (%) | 23.5 | 47.4 | 63.8 | 76.7 |
| Serum fasting glucose (mmol/l) | 5.1 ± 0.3 | 5.8 ± 0.4 | 7.2 ± 1.8 | 7.9 ± 2.1 |
| Serum 2-hour glucose (mmol/l) | 5.2 ± 1.1 | 7.0 ± 1.8 | 12.5 ± 3.6 | - |
| HbA1c [%] | 5.3 ± 0.3 | 5.8 ± 0.4 | 6.2 ± 0.9 | 6.7 ± 1.1 |
| HbA1c (mmol/mol) | 34 ± 4 | 40 ± 4 | 44 ± 10 | 50 ± 12 |
| Parental diabetes (%) | ||||
| Yes b | 27.9 | 34.4 | 40.4 | 47.2 |
| No | 63.6 | 55.0 | 42.6 | 39.1 |
| Don’t know | 8.5 | 10.6 | 17.0 | 13.7 |
| Smoking (%) | ||||
| Current | 17.6 | 15.0 | 7.5 | 8.6 |
| Former | 35.0 | 41.4 | 38.3 | 47.6 |
| Never | 47.4 | 43.6 | 54.3 | 43.8 |
| Physical activity (inactive) (%) c | 35.1 | 44.2 | 66.0 | 60.9 |
| School leaving certificate (%) | ||||
| Low | 39.5 | 54.8 | 62.8 | 65.7 |
| Intermediate | 31.0 | 21.4 | 20.2 | 17.6 |
| High | 29.4 | 23.8 | 17.0 | 16.7 |
| Medical check-up at least once (%) | 56.1 | 51.9 | 47.3 | 50.9 |
| Perception of diabetes as a serious or very serious disease (%) | 90.5 | 86.9 | 75.5 | - |
| Subjective health (%) | ||||
| Very good | 17.1 | 8.4 | 5.3 | 6.9 |
| Good | 67.2 | 71.9 | 63.8 | 59.2 |
| Less good | 14.8 | 17.6 | 24.5 | 27.5 |
| Poor | 0.8 | 2.1 | 6.4 | 6.4 |
a Mean ± standard deviation, median (first quartile, third quartile), or proportion (%)
b Father, mother or both had diabetes
c Persons were defined as physically inactive if they exercised regularly less than at least one hour per week