Table 1 Characteristics of the included studies for the meta-analysis of insulin sensitivity
Author Year | Study design | Subjects (n/m:f) | Subject characteristics (Age, body mass index [kg/m2], other information) | Duration of caffeine abstention | Caffeine dose Mode of administration Placebo | Insulin sensitivity assessment method |
|---|---|---|---|---|---|---|
Battram 2006 | Randomized Double-blind Crossover | 11 11:0 | 23.3 ± 0.6 y Healthy, non-smokers Body weight: 76.4 ± 1.9 kg Percent body fatness 15.6 ± 2.3 | 7 days | 4.45 mg/kg caffeine Orally Dextrose | OGTT aMatsuda & DeFronzo Equation [39] |
Greenberg 2010 | Randomized Single-blind Crossover | 11 11:0 | 23.5 ± 5.7 y 23.6 ± 4.2 kg/m2 1 week prior: maintain stable diet, exercise, and alcohol intake No caffeinated drinks, foods, or medications No smoking No alcohol or exercise 48 h prior | 48 h | 6 mg/kg caffeine Orally Caffeine vs warm water Caffeinated coffee vs decaffeinated coffee | OGTT Matsuda & DeFronzo Equation [39] |
Keijzers 2002 | Randomized Double-blind Crossover | 12 6:6 | 20–28 y Nonsmoking 21.9 ± 2.7 kg/m2 (lean) | 72 h | 3 mg/kg caffeine Intravenously NaCl 0.9% | Hyperinsulinemic- euglycemic glucose clamp |
Moisey 2008 | Randomized Single-blind Crossover | 10 10:0 | 23.3 ± 1.1 y 25.3 ± 1.05 kg/m2 Non-smokers, healthy | 48 h | 5 mg/kg caffeinated coffe Orally Decaffeinated coffee | OGTT Belfiore formula [39] |
Moisey 2010 | Randomized Double-blind Crossover | 10 10:0 | 23.3 ± 1 y 23.4 ± 0.8 kg/m2 Non-smokers, healthy 3/10 Non-caffeine users | 48 h | 5 mg/kg caffeinated coffee Orally Decaffeinated coffee | OGTT Matsuda & DeFronzo Equation [39] |
Petrie 2004 | Randomized Double-blind Crossover | 9 9:0 | 19–34 y No history of disease (diabetes mellitus) No drug or alcohol abuse Sedentary 34.0 ± 1.0 kg/m2 (obese) | 48 h | 5 mg/kg caffeine Orally Dextrose | OGTT Matsuda & DeFronzo Equation [39] |
Thong 2002 | Randomized Double-blind Crossover | 7 7:0 | 24 ± 1 y 23 cpe ± 1 kg/m2 Lean | 48 h | 5 mg/kg caffeine Orally 5 mg/kg dextrose | OGTT Matsuda & DeFronzo Equation [39] |