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. 2025 Mar 14;14:e25. doi: 10.1017/jns.2025.13

Table 3.

Subgroup analysis to assess the effect of green tea supplementation on inflammatory markers and antioxidant status

Variable Number of effect sizes WMD (95% CI) p-Valuea I2 (%)b p for
heterogeneityc 		p for between subgroup
heterogeneityd
CRP
Overall 22 0.01 (−0.14, 0.15) 0.914 94.0 < 0.001 –
BMI (kg/m2)   < 0.001
  <30 14 −0.12 (−0.37, 0.12) 0.332 94.1 < 0.001  
  ≥30 7 0.19 (−0.04, 0.43) 0.108 92.8 < 0.001
Dosage (mg/day)   0.036
  <500 8 0.30 (−0.02, 0.64) 0.069 92.9 < 0.001  
  ≥500 14 −0.12 (−0.31, 0.06) 0.199 94.7 < 0.001
Duration (weeks)   0.010
  ≤8 15 0.08 (−0.09, 0.27) 0.353 90.4 < 0.001  
  >8 7 −0.11 (−0.46, 0.23) 0.523 96.9 < 0.001
Health status   < 0.001
  Healthy 4 −0.13 (−0.68, 0.40) 0.622 88.4 < 0.001  
  Unhealthy 18 0.05 (−0.10, 0.21) 0.496 94.3 < 0.001
Type of intervention   0.151
  Green tea extract 17 −0.13 (−0.28, 0.02) 0.090 94.2 < 0.001  
  Brewed green tea 5 1.00 (−0.12, 2.13) 0.081 94.1 < 0.001
Location of study   < 0.001
  Asia 12 −0.17 (−0.42, 0.06) 0.154 94.9 < 0.001  
  Non-Asia 10 −0.005 (−0.02, 0.01) 0.688 91.5 < 0.001
Gender   < 0.001
  Both 16 0.12 (−0.12, 0.37) 0.323 94.3 < 0.001  
  Male 2 −0.36 (−1.05, 0.31) 0.291 90.4 0.001
  Female 4 0.07 (−0.11, 0.27) 0.442 89.6 < 0.001
IL-6
Overall 12 −0.34 (−0.94, 0.26) 0.271 84.2 < 0.001 –
BMI (kg/m2)   0.001
  <30 7 0.09 (−0.44, 0.64) 0.731 76.8 < 0.001  
  ≥30 5 −0.97 (−3.53, 1.40) 0.421 87.5 < 0.001
Dosage (mg/day)   0.037
  <500 3 −0.41 (−0.79, −0.03) 0.032 0.0 0.734  
  ≥500 9 −0.28 (−1.13, 0.56) 0.513 87.6 < 0.001
Duration (weeks)   < 0.001
  ≤8 10 −0.55 (−1.11, 0.007) 0.053 80.9 < 0.001  
  >8 1 −1.90 (−3.86, 0.06) 0.058 – –
Health status   < 0.001
  Healthy 4 0.70 (−0.63, 2.04) 0.299 84.7 < 0.001  
  Unhealthy 8 −1.05 (−2.03, −0.07) 0.036 80.1 < 0.001
Type of intervention   0.755
  Green tea extract 10 −0.38 (−1.03, 0.25) 0.238 87.0 < 0.001  
  Brewed green tea 2 0.22 (−1.22, 1.67) 0.765 0.0 0.683
Location of study   0.001
  Asia 7 −0.06 (−0.58, 0.45) 0.801 79.9 < 0.001  
  Non-Asia 5 −0.37 (−2.93, 2.16) 0.770 86.3 < 0.001
Gender   < 0.001
  Both 7 −0.36 (−1.25, 0.52) 0.423 41.2 0.116  
  Male 3 0.63 (−0.43, 1.70) 0.243 90.0 < 0.001
  Female 2 −2.21 (−5.63, 1.20) 0.204 94.5 < 0.001
TNF-α
Overall 9 −0.07 (−0.42, 0.28) 0.696 90.3 < 0.001 –
BMI (kg/m2)   < 0.001
  <30 6 0.28 (−0.15, 0.72) 0.199 84.4 < 0.001  
  ≥30 3 −0.60 (−0.91, −0.29) < 0.001 67.9 < 0.001
Dosage (mg/day)   < 0.001
  <500 2 −0.44 (−1.13, 0.25) 0.212 55.5 0.134  
  ≥500 7 0.02 (−0.41, 0.28) 0.909 89.5 < 0.001
Duration (weeks)   < 0.001
  ≤8 7 −0.16 (−0.42, 0.08) 0.199 74.6 0.001  
  >8 1 −0.67 (−0.89, −0.44) < 0.001 – –
Health status   0.019
  Healthy 4 0.60 (−0.31, 1.52) 0.196 90.6 < 0.001  
  Unhealthy 5 −0.39 (−0.80, 0.01) 0.057 91.2 < 0.001
Type of intervention   0.999
  Green tea extract 8 −0.05 (−0.43, 0.32) 0.772 91.6 < 0.001  
  Brewed green tea 1 −0.14 (−0.69, 0.41) 0.618 – –
Location of study   < 0.001
  Asia 5 0.28 (−0.32, 0.89) 0.358 89.8 < 0.001  
  Non-Asia 4 −0.43 (−0.66, −0.20) < 0.001 50.3 0.110
Gender   < 0.001
  Both 4 −0.33 (−0.72, 0.04) 0.087 53.6 0.091  
  Male 3 0.63 (−1.41, 2.67) 0.544 94.9 < 0.001
  Female 2 −0.16 (−0.61, 0.28) 0.477 93.7 < 0.001
TAC
Overall 15 0.09 (0.05, 0.13) < 0.001 84.9 < 0.001 –
BMI (kg/m2)   < 0.001
  <30 7 0.09 (0.06, 0.11) < 0.001 58.1 0.026  
  ≥30 5 0.16 (0.12, 0.19) < 0.001 0.0 0.592
Dosage (mg/day)   < 0.001
  <500 7 0.08 (−0.003, 0.17) 0.058 91.9 < 0.001  
  ≥500 8 0.09 (0.07, 0.11) < 0.001 0.0 0.581
Duration (weeks)   0.238
  ≤8 8 0.08 (0.06, 0.11) < 0.001 52.4 0.040  
  >8 7 0.06 (−0.03, 0.17) 0.209 92.2 < 0.001
Health status   0.648
  Healthy 3 0.07 (0.03, 0.11) < 0.001 77.5 0.012  
  Unhealthy 12 0.08 (0.02, 0.15) 0.008 86.8 < 0.001
Type of intervention   < 0.001
  Green tea extract 10 0.07 (0.006, 0.14) 0.033 87.9 < 0.001  
  Brewed green tea 5 0.09 (0.08, 0.11) < 0.001 0.0 0.601
Location of study   0.860
  Asia 9 0.10 (0.06, 0.14) < 0.001 55.9 0.020  
  Non-Asia 6 0.06 (−0.02, 0.14) 0.146 93.3 < 0.001
Gender   0.009
  Both 11 0.08 (0.03, 0.14) 0.003 87.5 < 0.001  
  Male 3 0.07 (−0.01, 0.16) 0.085 38.5 0.197
  Female 1 0.14 (0.08, 0.19) < 0.001 – –
MDA
Overall 14 −0.40 (−0.63,−0.18) < 0.001 99.2 < 0.001 –
BMI (kg/m2)   < 0.001
  <30 9 −0.43 (−0.71, −0.15) 0.002 99.5 < 0.001  
  ≥30 2 −0.60 (−1.58, 0.37) 0.227 92.0 < 0.001
Dosage (mg/day)   < 0.001
  <500 5 −0.03 (−0.07, 0.01) 0.130 61.5 < 0.001  
  ≥500 9 −0.52 (−0.95, −0.10) 0.015 98.8 0.034
Duration (weeks)   0.113
  ≤8 10 −0.42 (−0.82, −0.03) 0.033 99.5 < 0.001  
  >8 4 −0.32 (−0.76, 0.10) 0.135 90.3 < 0.001
Health status   < 0.001
  Healthy 7 −0.43 (−0.83, −0.04) 0.013 99.6 < 0.001  
  Unhealthy 7 −0.37 (−0.67, −0.07) 0.030 84.2 < 0.001
Type of intervention   < 0.001
  Green tea extract 10 −0.43 (−0.69, −0.16) 0.001 99.4 < 0.001  
  Brewed green tea 4 −0.32 (−1.10, 0.44) 0.410 95.5 < 0.001
Location of study   < 0.001
  Asia 9 −0.58 (−1.05, −0.11) 0.015 99.5 < 0.001  
  Non-Asia 5 −0.02 (−0.17, 0.13) 0.794 84.3 < 0.001
Gender   < 0.001
  Both 9 −0.31 (−0.53, −0.10) 0.004 92.6 < 0.001  
  Male 3 −0.13 (−0.38, 0.11) 0.297 60.8 0.078
  Female 2 −1.001 (−1.17, −0.82) < 0.001 92.6 < 0.001
GPX
Overall 10 3.90 (1.85, 5.95) < 0.001 93.1 < 0.001 –
BMI (kg/m2)   < 0.001
  <30 3 9.53 (0.21, 18.86) 0.045 94.3 < 0.001  
  ≥30 4 4.29 (−0.01, 8.60) 0.051 92.0 < 0.001
Dosage (mg/day)   0.584
  <500 4 3.16 (−1.62, 7.94) 0.195 93.6 < 0.001  
  ≥500 6 4.58 (1.49, 7.67) 0.004 94.0 < 0.001
Duration (weeks)   < 0.001
  ≤8 6 6.95 (3.12, 10.78) < 0.001 89.2 < 0.001  
  >8 4 0.53 (−1.17, 2.23) 0.540 87.9 < 0.001
Health status   < 0.001
  Healthy 5 7.12 (2.00, 12.24) 0.006 90.4 < 0.001  
  Unhealthy 5 1.71 (−0.36, 3.79) 0.106 92.4 < 0.001
Type of intervention   < 0.001
  Green tea extract 7 3.55 (1.04, 6.07) 0.006 93.0 < 0.001  
  Brewed green tea 3 4.48 (1.43, 7.52) 0.004 84.7 0.001
Location of study   < 0.001
  Asia 4 7.75 (0.41, 15.11) 0.039 94.8 < 0.001  
  Non-Asia 6 2.21 (0.27, 4.15) 0.025 91.5 < 0.001
Gender   < 0.001
  Both 8 2.21 (0.41, 4.02) 0.016 91.4 < 0.001  
  Male – – – – –
  Female 2 13.72 (10.36, 17.40) < 0.001 0.0 0.809
SOD
Overall 6 17.21 (3.24, 31.19) 0.016 92.1 < 0.001 –
BMI (kg/m2)   0.500
  <30 2 23.14 (−23.86, 70.15) 0.335 96.4 < 0.001  
  ≥30 2 98.54 (−96.67, 293.75) 0.322 97.0 < 0.001
Dosage (mg/day)   0.015
  <500 2 0.001 (−0.37, 0.38) 0.997 0.0 0.693  
  ≥500 4 47.06 (0.34, 93.78) 0.048 94.8 < 0.001
Duration (weeks)   < 0.001
  ≤8 1 48.00 (30.26, 65.73) < 0.001 – –  
  >8 5 6.56 (−5.95, 19.09) 0.304 88.6 < 0.001
Health status   0.499
  Healthy 3 68.17 (10.11, 126.24) 0.021 96.8 < 0.001  
  Unhealthy 3 1.71 (−3.16, 6.59) 0.490 0.0 0.673
Type of intervention   0.499
  Green tea extract 3 1.71 (−3.16, 6.59) 0.490 0.0 0.673  
  Brewed green tea 3 68.17 (10.11, 126.24) 0.021 96.8 < 0.001
Location of study   < 0.001
  Asia 3 8.83 (−5.19, 22.87) 0.217 94.2 < 0.001  
  Non-Asia 3 16.84 (−24.45, 58.13) 0.424 78.8 0.009
Gender   –
  Both 6 17.21 (3.24, 31.19) 0.016 92.1 < 0.001  
  Male – – – – –
  Female – – – – –

Abbreviation: WMD: Weighted Mean Difference, CI: Confidence Interval, CRP: C-reactive protein, IL-6: Interleukin-6, TNF-a: Tumour Necrosis Factor Alpha, TAC: Total Antioxidant Capacity, MDA: Malondialdehyde, GPX: Glutathione Peroxidase, SOD: Superoxide Dismutase, BMI; Body Mass Index.

aRefers to the mean (95% CI).

bInconsistency, percentage of variation across studies due to heterogeneity.

cObtained from the Q-test.

dObtained from the fixed-effects model.