Table 1

Characteristics of the study participants at KORA F4, overall and stratified for diabetes status*

Total study cohortNormal glucose tolerancePre-diabetesP value†Type 2 diabetesP value‡
n15141091275–148–
Male sex, n (%)736 (49)501 (46)148 (54)0.02§87 (59)0.004§
Age (years)56.6±12.953.5±12.463.9±10.8<0.001¶66.3±9.2<0.001¶
BMI (kg/m2)27.4±4.626.4±4.229.3±4.6<0.001¶30.7±4.5<0.001¶
Waist circumference (cm)93.0±13.589.9±12.799.4±12.4<0.001¶103.9±11.1<0.001¶
HbA1c (%)5.4 (5.2; 5.6)5.3 (5.1; 5.5)5.6 (5.3; 5.8)<0.001**6.2 (5.9; 6.7)<0.001**
HbA1c (mmol/mol)35.5 (32.2; 38.8)34.4 (32.2.; 36.6)37.7 (34.4; 39.9)<0.001**44.3 (40.7; 49.7)<0.001**
Arterial hypertension, n (%)††590 (39)314 (29)160 (58)<0.001§116 (78)<0.001§
Physically inactive, n (%)631 (42)410 (38)138 (50)<0.001§83 (56)<0.001§
Proinsulin (pmol/L)3.0 (2.0; 4.8)2.5 (1.8; 3.7)4.3 (2.9; 6.7)<0.001**7.0 (4.8; 11.2)<0.001**
Insulin (pmol/L)53.4 (38.4; 78.0)48.0 (34.8; 66.0)72.0 (50.5; 108.0)<0.001**90.0 (60.0; 132.0)<0.001**
Proinsulin to insulin ratio0.055 (0.039; 0.078)0.052 (0.038; 0.072)0.059 (0.042; 0.083)0.002**0.078 (0.054; 0.119)<0.001**
Previous stroke, n (%)34 (2)18 (2)7 (3)0.46§9 (6)0.002§
Previous myocardial infarction, n (%)41 (3)17 (2)10 (4)0.048§14 (9)<0.001§

  • *Mean±SD, median (first quartile; third quartile), or number of participants (proportion in %).

  • †The p value is related to the null hypothesis of no difference between participants with normal glucose tolerance and pre-diabetes.

  • ‡The p value is related to the null hypothesis of no difference between participants with normal glucose tolerance and type 2 diabetes.

  • §χ2 test.

  • ¶T-test.

  • **Mann-Whitney U test.

  • ††Defined as systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure ≥90 mm Hg and/or use of antihypertensive medication, given that the participants were aware of being hypertensive.

  • BMI, body mass index; KORA F4, Cooperative Health Research in the Region of Augsburg F4 (2006–2008) study.