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

Overall effect size

12

-2.35

−3.78, −0.92

0.001

45.8

0.037

 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

  ≥ 8

11

−2.13

−3.12, −1.13

< 0.001

51.1

0.025

  < 8

1

−1.40

−4.35, 1.55

0.35

–

–

 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

 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

Overall effect size

7

−0.63

−1.11, − 0.15

0.01

49.4

0.07

 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

 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

 Overall effect size

15

−3.17

−11.82, 5.49

0.47

59.1

0.002

 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

  ≥ 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

 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

 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

 Overall effect size

16

−4.51

−8.39, −0.64

0.02

44.1

0.03

 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

  ≥ 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

 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

 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

 Overall effect size

15

−2.02

−5.58, 1.54

0.27

47.6

0.02

 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

  ≥ 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

 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

 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

 Overall effect size

15

1.08

−0.22, 2.38

0.10

37.6

0.07

 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

  ≥ 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

 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

 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