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. 2020 Feb 19;11(4):790–814. doi: 10.1093/advances/nmaa010

TABLE 2.

Subgroup meta-analysis results for CVD-mortality and CVD-events outcomes1

CVD mortality CVD events
n Pooled adjusted RR (95% CI) P for pooled RR I 2, % n Pooled adjusted RR (95% CI) P for pooled RR I 2, %
Overall 19 0.962 (0.939, 0.984) 0.001 72.4** 7 0.982 (0.961, 1.003) 0.085 76.5**
Sex
 Both sexes 7 0.932 (0.893, 0.973) 0.001 62.9** 7 0.982 (0.961, 1.003) 0.085 76.5**
 Female 5 0.973 (0.926, 1.021) 0.267 72.0** 0 n/a n/a n/a
 Male 7 0.980 (0.945, 1.017) 0.289 72.5** 0 n/a n/a n/a
Tea type
 Black tea 11 0.974 (0.935, 1.015) 0.212 59.5** 4 0.985 (0.938, 1.034) 0.542 80.8**
 Green tea 8 0.952 (0.923, 0.981) 0.002 81.6** 1 0.966 (0.951, 0.982) <0.0001 n/a
 All tea 0 n/a n/a n/a 2 0.927 (0.785, 1.095) 0.0372 71.7*
Age group
 Adults 15 0.975 (0.955, 0.994) 0.012 58.5** 6 0.983 (0.964, 1.003) 0.097 76.9**
 Elderly 4 0.888 (0.825, 0.955) 0.001 59.5* 1 0.749 (0.570, 0.984) 0.038 n/a
Region
 United States 3 0.991 (0.957, 1.027) 0.637 0.0 2 0.925 (0.788, 1.085) 0.338 69.1*
 Asia 8 0.952 (0.923, 0.981) 0.002 81.6** 2 0.978 (0.958, 0.999) 0.045 83.5**
 Europe 7 0.978 (0.915, 1.046) 0.520 70.2** 2 0.881 (0.699, 1.109) 0.281 67.8*
 Australia 1 0.920 (0.862, 0.982) 0.012 n/a 0 n/a n/a n/a
 Iran 0 n/a n/a n/a 1 1.040 (1.005, 1.076) 0.023 n/a
Risk of bias
 Exposure ascertainment2
  A 7 0.969 (0.918, 1.022) 0.246 77.8** 1 0.959 (0.926, 0.993) 0.020 n/a
  B 5 0.981 (0.949, 1.014) 0.258 64.3** 5 0.986 (0.957, 1.016) 0.352 82.6**
  C 7 0.932 (0.884, 0.983) 0.009 75.5** 1 0.982 (0.955, 1.010) 0.205 n/1
 No outcomes at start3
  A 17 0.973 (0.953, 0.993) 0.009 59.4** 7 0.982 (0.961, 1.003) 0.085 76.5**
  B 2 0.886 (0.830, 0.946) <0.0001 62.7* 0 n/a n/a n/a
 Comparability4
  AB 17 0.973 (0.953, 0.993) 0.009 59.4** 7 0.982 (0.961, 1.003) 0.085 76.5**
  A 1 0.920 (0.862, 0.982) 0.012 n/a 0 n/a n/a n/a
  B 1 0.860 (0.820, 0.902) <0.0001 n/a 0 n/a n/a n/a
 Adequate follow-up5
  A 8 0.979 (0.927, 1.035) 0.463 68.3** 1 0.982 (0.955, 1.010) 0.205 n/a
  B 10 0.964 (0.946, 0.983) <0.0001 49.6** 4 0.972 (0.951, 0.994) 0.014 75.2**
  C 1 0.860 (0.820, 0.902) <0.0001 n/a 1 1.040 (1.005, 1.076) 0.023 n/a
  D 0 n/a n/a n/a 1 0.828 (0.688, 0.995) 0.044 n/a
1

n = number of studies. *,**Indicates significant heterogeneity based on Q-test: *P < 0.1, **P < 0.05. CVD, cardiovascular disease; n/a, not applicable.

2

Ascertainment of exposure: A, multiple dietary exposure assessments during follow-ups and having internal or external calibration of the dietary assessment instrument, or single dietary exposure assessment at baseline and having internal or external calibration of dietary assessment for tea or flavonoid consumption specifically; B, single dietary exposure assessment at baseline and having internal or external calibration of the dietary assessment instrument; and C, single dietary exposure assessment at baseline and unclear validity of the dietary assessment instrument.

3

Demonstration that the outcome of interest was not present at the start of the study: A, yes; B, no.

4

Comparability of cohorts on the basis of the design or analysis: A, study controls for age, sex, socioeconomic characteristics (e.g., education, income), any anthropometric measure (BMI, weight, etc.), medication for or history/existing diseases if applicable [choose this when 1) must include all of them or 2) if they describe having a variable selection process, and justify why they did not include some of these]; B, study controls for any additional factor such as other dietary factors or physical activity; C, both A and B; and D, neither A nor B. Note that AB indicates both A and B.

5

Adequacy of follow-up of cohorts: A, complete follow-up, all subjects accounted for (e.g., mortality as results and use death record linkage data); B, subjects lost to follow-up unlikely to introduce bias—small number lost (≤20%), or >20% lost to follow-up, with description provided of those lost; C, lost to follow-up rate ≥20% without description of those lost or likely to bring bias; and D, no statement.