Table 2: Mean changes of glucose metabolism parameters and serum adiponectin and C-reactive protein at 8 weeks of intervention as compared with the baseline values.

ParameterCaffeinated coffee (n = 17)Decaffeinated coffee (n = 15)No coffee (n = 13)P value*

Plasma glucose (mmol/L)
 Fasting0.0 (0.4)0.1 (0.4)−0.0 (0.2)0.55
 2-hour−1.1 (2.4)−0.5 (2.2)−0.3 (1.6)0.51
 AUC−0.7 (2.3)−0.3 (1.8)−0.6 (1.2)0.62
Plasma insulin (pmol/L)
 Fasting3 (21)5 (19)−7 (24)0.53
 2-hour−44 (315)−6 (192)18 (319)0.99
 AUC7 (234)−5 (291)−12 (214)0.82
Composite ISI−0.2 (1.5)−0.1 (1.9)0.2 (0.8)0.46
HOMA-IR0.1 (0.9)0.2 (0.8)−0.3 (1.0)0.27
Total adiponectin ( g/mL)0.2 (0.9)−0.1 (0.5)−0.0 (0.7)0.15
HMW adiponectin ( g/mL)0.1 (0.6)−0.1 (0.6)0.0 (0.7)0.48
C-reactive protein (mg/L)−0.39 (1.54)0.18 (0.62)−0.12 (0.57)0.80

AUC: area under the curve; HMW: high-molecular weight; HOMA-IR: homeostasis model assessment of insulin resistance; ISI: insulin sensitivity index.
Values in parentheses are standard deviations.
*Overall difference based on Kruskal-Wallis test.
Hour was used for the time scale in the oral glucose tolerance test.
Number of the subjects in the decaffeinated coffee group was 13.