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Table 2 Subgroup analysis on the effects of GCE supplementation on glycemic and lipid measures

From: The effects of green coffee extract supplementation on glycemic indices and lipid profile in adults: a systematic review and dose-response meta-analysis of clinical trials

  Effect size, n WMD1 95% CI1 P-value2 Heterogeneity
I2 (%)3 P-heterogeneity4
The effect of GCE on FBS
Overall effect size 12 -2.35 −3.78, −0.92 0.001 45.8 0.037
Participants’ gender
 Male 2 −1.32 −3.87, 1.22 0.31 0.0 0.92
 Female 4 −1.13 −2.47, 0.21 0.098 57.5 0.07
 Both genders 6 −3.55 −5.10, −2.01 < 0.001 36.3 0.17
Intervention duration (week)
  ≥ 8 11 −2.13 −3.12, −1.13 < 0.001 51.1 0.025
  < 8 1 −1.40 −4.35, 1.55 0.35
Baseline FBS
 Elevated (≥100 mg/dL) 3 −5.28 −7.93, −2.63 < 0.001 44.10 0.17
 Normal (< 100 mg/dL) 9 −1.59 −2.59, −0.58 0.002 24.20 0.23
Compliance
 Acceptable 5 −3.59 −5.15, −2.04 < 0.001 47.6 0.11
 Unacceptable/Unclear 7 −1.16 −2.34, 0.02 0.053 15.5 0.31
The effect of GCE on insulin levels
Overall effect size 7 −0.63 −1.11, − 0.15 0.01 49.4 0.07
Participants’ gender
 Female 3 −0.31 −0.52, − 0.10 0.004 54.4 0.11
 Both genders 4 −0.77 −1.21, − 0.33 0.001 26.0 0.26
Compliance
 Acceptable 4 −0.77 −1.21, − 0.33 0.001 26.0 0.26
 Unacceptable/Unclear 3 −0.31 −0.52, − 0.10 0.004 54.4 0.11
The effect of GCE on TG levels
 Overall effect size 15 −3.17 −11.82, 5.49 0.47 59.1 0.002
Participants’ gender
 Male 5 −1.05 −11.70, 9.60 0.85 0.0 0.99
 Female 4 2.76 −5.18, 10.70 0.49 79.6 0.002
 Both genders 6 −7.83 −15.22, −0.44 0.04 68.0 0.008
Intervention duration (week)
  ≥ 8 11 −2.87 −8.27, 2.53 0.29 70.6 < 0.001
  < 8 4 −1.21 −11.91, 9.50 0.83 0.0 0.99
Baseline TG
 Elevated (≥150 mg/dL) 4 −4.58 −12.77, 3.60 0.27 74.9 0.008
 Normal (< 150 mg/dL) 11 −1.44 −7.41, 4.53 0.64 54.4 0.02
Compliance
 Acceptable 8 −6.14 −12.44, 0.17 0.06 57.3 0.02
 Unacceptable/Unclear 7 2.55 −4.93, 10.03 0.50 59.5 0.02
The effect of GCE on TC levels
 Overall effect size 16 −4.51 −8.39, −0.64 0.02 44.1 0.03
Participants’ gender
 Male 5 −1.51 −6.78, 3.75 0.57 5.6 0.38
 Female 5 −5.29 −8.87, −1.71 0.004 44.2 0.13
 Both genders 6 −7.48 −12.11, −2.86 0.002 60.4 0.03
Intervention duration (week)
  ≥ 8 12 −6.11 −8.91, −3.30 < 0.001 45.9 0.04
  < 8 4 −1.22 −6.65, 4.22 0.66 26.0 0.26
Baseline TC
 Elevated (≥200 mg/dL) 8 −6.06 −9.01, − 3.12 < 0.001 26.2 0.22
 Normal (< 200 mg/dL) 8 −2.60 −7.28, 2.09 0.28 55.8 0.03
Compliance
 Acceptable 8 −4.88 −8.53, −1.23 0.009 59.4 0.02
 Unacceptable/Unclear 8 −5.26 −8.66, −1.85 0.003 27.0 0.21
The effect of GCE on LDL levels
 Overall effect size 15 −2.02 −5.58, 1.54 0.27 47.6 0.02
Participants’ gender
 Male 5 0.58 −4.59, 5.76 0.83 3.4 0.39
 Female 4 −6.96 −10.01, −3.90 < 0.001 61.1 0.05
 Both genders 6 −1.44 −5.45, 2.57 0.48 25.5 0.24
Intervention duration (week)
  ≥ 8 11 −5.01 −7.42, −2.61 < 0.001 47.9 0.04
  < 8 4 1.70 −3.79, 7.19 0.54 0.0 0.44
Baseline LDL
 Elevated (≥130 mg/dL) 2 0.10 −5.73, 5.53 0.97 28.9 0.24
 Normal (< 130 mg/dL) 13 −4.63 −7.02, −2.24 < 0.001 48.3 0.03
Compliance
 Acceptable 8 0.01 −3.38, 3.41 0.99 11.1 0.34
 Unacceptable/Unclear 7 −6.79 −9.68, −3.90 < 0.001 39.4 0.13
The effect of GCE on HDL levels
 Overall effect size 15 1.08 −0.22, 2.38 0.10 37.6 0.07
Participants’ gender
 Male 5 0.06 −2.16, 2.27 0.96 0.0 0.99
 Female 4 2.92 2.46, 3.39 < 0.001 62.0 0.05
 Both genders 6 0.63 −1.37, 2.62 0.54 0.0 0.59
Intervention duration (week)
  ≥ 8 11 2.79 2.34, 3.24 < 0.001 43.0 0.06
  < 8 4 0.18 −2.12, 2.49 0.88 0.0 0.99
Baseline HDL
 Low (< 40 mg/dL) 5 2.87 2.41, 3.33 < 0.001 56.4 0.06
 Normal (≥40 mg/dL) 10 0.34 −1.36, 2.04 0.69 0.0 0.81
Compliance
 Acceptable 8 0.51 −1.06, 2.09 0.52 0.0 0.91
 Unacceptable/Unclear 7 2.88 2.42, 3.14 < 0.001 48.7 0.07
  1. 1Obtained from the fixed-effects model
  2. 2Refers to the mean (95% CI)
  3. 3Inconsistency, percentage of variation across studies due to heterogeneity
  4. 4Obtained from the Q-test
  5. Abbreviations: GCE green coffee extract, WMD weighted mean difference, CI confidence interval, TG triglycerides, TC total cholesterol, LDL low-density lipoprotein, HDL high-density lipoprotein, FBG fasting blood glucose