Table 3: Mean changes of glucose metabolism parameters and serum adiponectin and C-reactive protein at 16 weeks of intervention as compared with the baseline values.

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

Plasma glucose (mmol/L)
 Fasting−0.0 (0.5)0.0 (0.7)−0.0 (0.5)0.88
 2-hour−1.3 (2.2)0.1 (2.6)0.7 (1.4)0.07
 AUC−1.4 (2.6)−0.3 (3.3)0.3 (1.6)0.08
Plasma insulin (pmol/L)
 Fasting4 (23)5 (20)5 (16)0.94
 2-hour−2 (515)102 (896)90 (260)0.40
 AUC115 (526)63 (771)36 (252)0.94
Composite ISI−0.2 (1.7)−0.4 (1.5)−0.3 (1.0)0.85
HOMA-IR0.1 (0.9)0.2 (0.8)0.1 (0.7)0.86
Total adiponectin ( g/mL)0.4 (0.9)0.0 (0.5)0.4 (1.1)0.45
HMW adiponectin ( g/mL)0.3 (0.8)−0.0 (0.5)0.3 (0.7)0.40
C-reactive protein (mg/L)−0.43 (1.33)0.42 (1.16)−0.21 (0.66)0.63

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.
P < 0.05 as compared with the baseline and as compared with the noncoffee group.
Hour was used for the time scale in the oral glucose tolerance test.