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

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.

Parameter	Caffeinated 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)
Fasting	4 (23)	5 (20)	5 (16)	0.94
2-hour	−2 (515)	102 (896)	90 (260)	0.40
AUC^‡	115 (526)	63 (771)	36 (252)	0.94
Composite ISI	−0.2 (1.7)	−0.4 (1.5)	−0.3 (1.0)	0.85
HOMA-IR	0.1 (0.9)	0.2 (0.8)	0.1 (0.7)	0.86
Total adiponectin (𝜇g/mL)	0.4 (0.9)	0.0 (0.5)	0.4 (1.1)	0.45
HMW adiponectin (𝜇g/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.