Effects of 16-Week Consumption of Caffeinated and Decaffeinated Instant Coffee on Glucose Metabolism in a Randomized Controlled Trial

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.

Parameter	Caffeinated coffee (n = 17)	Decaffeinated coffee (n = 15)	No coffee (n = 13)	P value*
Plasma glucose (mmol/L)
Fasting	0.0 (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)
Fasting	3 (21)	5 (19)	−7 (24)	0.53
2-hour	−44 (315)	−6 (192)	18 (319)	0.99
AUC^†	7 (234)	−5 (291)	−12 (214)	0.82
Composite ISI	−0.2 (1.5)	−0.1 (1.9)	0.2 (0.8)	0.46
HOMA-IR	0.1 (0.9)	0.2 (0.8)	−0.3 (1.0)	0.27
Total adiponectin (𝜇g/mL)^‡	0.2 (0.9)	−0.1 (0.5)	−0.0 (0.7)	0.15
HMW adiponectin (𝜇g/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.