Table 3 Subgroup analyses of CLA supplementation on glycemic control, adipokine, cytokine, malondialdehyde and liver function enzymes in subjects with metabolic disorders

Subgroup analyses of CLA on serum FBG (mg/dL)

Overall effect

12

4.49 (2.39, 6.59)

 < 0.001

 < 0.001

97.1%

Baseline FBG (mg/dl)

 ≥ 100

9

5.90 (1.40, 10.40)

0.010

 < 0.001

90.5%

0.205

 < 100

3

1.13 (-4.70, 6.96)

0.704

 < 0.001

94.6%

Trial duration (week)

 ≥ 12

7

6.24 (3.71, 8.77)

 < 0.001

 < 0.001

98.3%

0.040

 <12

5

1.07 (-3.17, 5.32)

0.620

0.065

54.8%

Intervention dose (g/day)

 ≥ 3

5

7.57 (-0.17, 15.33)

0.055

 < 0.001

94.8%

0.247

 <3

7

2.73 (0.04, 5.42)

0.046

 < 0.001

98.0%

Baselin BMI (kg/m²)

 Obese (> 30)

7

3.55 (-3.08, 10.18)

0.294

 < 0.001

93.5%

0.755

 Overweight (25–29.9)

5

4.70 (1.79, 7.61)

0.002

 < 0.001

98.6%

Sex

 Male

2

4.46 (0.92, 7.99)

0.013

0.120

58.7%

0.671

 Both

8

2.62 (0.17, 5.07)

0.036

 < 0.001

97.7%

 Female

2

8.27 (-23.21, 39.76)

0.607

 < 0.001

96.6%

Health status

 Metabolic syndrome

3

2.46 (-2.63, 7.55)

0.343

0.022

73.9%

0.012

 T2DM

5

10.50 (-0.57, 21.58)

0.063

 < 0.001

85.6%

 Hyperlipidemic

2

4.41 (1.05, 7.76)

0.010

 < 0.001

99.6%

 Hypertension

1

0.00 (-2.17, 2.17)

1.000

-

-

 NAFLD

1

-5.89 (-11.96, 0.18)

0.057

-

-

Subgroup analyses of CLA on serum fasting insulin (mU/L)

 Overall effect

12

0.16 (-0.69, 1.02)

0.702

0.828

0.0%

Trial duration (week)

 ≥ 12

7

0.26 (-0.77, 1.30)

0.613

0.619

0.0%

0.737

 <12

5

-0.04 (-1.57, 1.48)

0.951

0.718

0.0%

Intervention dose (g/day)

 ≥ 3

5

0.17 (-1.16, 1.50)

0.801

0.383

4.2%

0.802

 <3

7

-0.08 (-1.53, 1.37)

0.912

0.891

0.0%

Baselin BMI (kg/m²)

 Obese (> 30)

7

0.19 (-0.77, 1.16)

0.687

0.601

0.0%

0.891

 Overweight (25–29.9)

5

0.05 (-1.81, 1.91)

0.956

0.725

0.0%

Sex

 Male

2

3.62 (-6.42, 13.66)

0.480

0.351

0.0%

0.430

 Both

8

-0.43 (-1.77, 0.90)

0.523

0.811

0.0%

 Female

2

0.55 (-0.57, 1.68)

0.335

0.552

0.0%

Health status

 Metabolic syndrome

3

0.43 (-6.32, 7.20)

0.899

0.455

0.0%

0.998

 T2DM

5

0.06 (-1.17, 1.30)

0.923

0.305

17.3%

 Hyperlipidemic

2

-0.02 (-5.20, 5.16)

0.994

0.824

0.0%

 Hypertension

1

-2.00 (-16.74, 12.74)

0.790

-

-

 NAFLD

1

-0.16 (-2.57, 2.25)

0.897

-

-

Subgroup analyses of CLA on serum HbA1c (%)

 Overall effect

6

-0.03 (-0.17, 0.09)

0.567

0.038

57.6%

Baseline HbA1c (%)

 < 6.5

3

0.05 (-0.22, 0.11)

0.529

0.004

82.3%

0.989

 ≥ 6.5

3

-0.05 (-0.40, 0.28)

0.748

0.841

0.0%

Trial duration (week)

 ≥ 12

3

0.02 (-0.03, 0.08)

0.385

0.587

0.0%

0.138

 <12

3

-0.30 (-0.73, 0.12)

0.167

0.120

52.9%

Intervention dose (g/day)

 ≥ 3

3

0.02 (-0.03, 0.08)

0.385

0.587

0.0%

0.138

 <3

3

-0.30 (-0.73, 0.12)

0.167

0.120

52.9%

Baselin BMI (kg/m²)

 Obese (> 30)

4

-0.04 (-0.20, 0.11)

0.575

0.010

73.4%

0.859

 Overweight (25–29.9)

2

-0.08 (-0.47, 0.31)

0.680

0.602

0.0%

Sex

 Male

2

0.02 (-0.03, 0.08)

0.397

0.302

6.1%

0.144

 Both

4

-0.25 (-0.61, 0.11)

0.178

0.157

42.4%

Health status

 Metabolic syndrome

2

0.02 (-0.03, 0.08)

0.397

0.302

6.1%

0.006

 T2DM

3

-0.05 (-0.40, 0.28)

0.748

0.841

0.0%

 NAFLD

1

-0.67 (-1.09, -0.24)

0.002

-

-

Subgroup analyses of CLA on serum HOMA-IR

 Overall effect

11

0.34 (-0.11, 0.81)

0.140

 < 0.001

78.7%

Trial duration (week)

 ≥ 12

5

0.23 (-0.56, 1.03)

0.563

 < 0.001

87.1%

0.702

 <12

6

0.43 (-0.18, 1.05)

0.171

0.007

68.4%

Intervention dose (g/day)

 ≥ 3

5

0.38 (-0.28, 1.05)

0.255

 < 0.001

86.7%

0.931

 <3

6

0.34 (-0.41, 1.10)

0.373

0.005

70.1%

Baselin BMI (kg/m²)

 Obese (> 30)

7

0.27 (-0.26, 0.81)

0.321

 < 0.001

81.0%

0.516

 Overweight (25–29.9)

4

0.69 (-0.46, 1.86)

0.239

0.002

79.9%

Sex

 Male

2

0.34 (-0.31, 1.00)

0.301

0.800

0.0%

0.017

 Both

7

0.09 (-0.33, 0.52)

0.675

0.006

66.8%

 Female

2

1.27 (0.58, 1.97)

 < 0.001

0.289

11.2%

Health status

 Metabolic syndrome

1

0.23 (-1.87, 2.33)

0.830

-

-

0.371

 T2DM

4

1.15 (-0.03, 2.34)

0.056

 < 0.001

92.8%

 Hyperlipidemic

4

0.02 (-0.39, 0.44)

0.917

0.650

0.0%

 Hypertension

1

0.00 (-0.49, 0.49)

1.000

-

-

 NAFLD

1

-0.25 (-0.87, 0.37)

0.434

-

-

Subgroup analyses of CLA on serum CRP (mg/L)

 Overall effect

7

0.00 (-0.45, 0.46)

0.976

0.489

0.0%

 Baseline CRP (mg/L)

 ≥ 3

4

-0.52 (-1.47, 0.41)

0.273

0.636

0.0%

0.205

 < 3

3

0.17 (-0.36, 0.72)

0.523

0.348

5.4%

Trial duration (week)

 ≥ 12

2

0.00 (-1.44, 1.44)

1.000

1.000

0.0%

0.974

 <12

5

-0.02 (-0.61, 0.56)

0.931

0.245

26.5%

Intervention dose (g/day)

 ≥ 3

2

0.35 (-0.38, 1.10)

0.344

0.248

25.1%

0.159

 <3

5

-0.36 (-1.03, 0.31)

0.292

0.746

0.0%

Baselin BMI (kg/m²)

 Obese (> 30)

3

0.25 (-0.33, 0.84)

0.400

0.405

0.0%

0.166

 Overweight (25–29.9)

3

-0.13 (-0.93, 0.67)

0.748

0.977

0.0%

 Normal (18.5–24.9)

1

-1.48 (-3.22, 0.26)

0.096

-

-

Sex

 Male

2

0.35 (-0.38, 1.10)

0.344

0.248

25.1%

0.159

 Both

5

-0.36 (-1.03, 0.31)

0.292

0.746

0.0%

Health status

 T2DM

1

-0.19 (-1.15, 0.77)

0.699

-

-

0.861

 Hyperlipidemic

5

0.06 (-0.59, 0.73)

0.841

0.285

20.4%

 NAFLD

1

-0.33 (-2.09, 1.43)

0.715

-

-

Subgroup analyses of CLA on serum IL-6 (pg/ml)

 Overall effect

5

-0.44 (-0.86, -0.02)

0.037

0.078

52.3%

Intervention dose (g/day)

 ≥ 3

2

-0.32 (-0.66, 0.01)

0.064

0.101

62.8%

0.267

 <3

3

-1.48 (-3.50, 0.53)

0.150

0.169

43.8%

Baselin BMI (kg/m²)

 Obese (> 30)

3

-0.32 (-0.59, -0.05)

0.019

0.257

26.3%

0.059

 Overweight (25–29.9)

1

-0.80 (-1.77, 0.17)

0.107

-

-

 Normal (18.5–24.9)

1

-3.81 (-6.87, -0.74)

0.015

-

-

Sex

 Male

2

-0.32 (-0.66, 0.01)

0.064

0.101

62.8%

0.267

 Both

3

-1.48 (-3.50, 0.53)

0.150

0.169

43.8%

Health status

 T2DM

1

-0.80 (-1.77, 0.17)

0.107

0.023

73.6%

0.772

 Hyperlipidemic

3

-0.41 (-0.94, 0.11)

0.121

-

-

 NAFLD

1

0.08 (-4.85, 5.01)

0.975

-

-

Subgroup analyses of CLA on serum TNF-α (ng/l)

 Overall effect

4

0.26 (-0.16, 0.69)

0.232

0.141

45.0%

Subgroup analyses of CLA on serum adiponectin (µg/ml)

 Overall effect

5

-0.12 (-2.41, 2.17)

0.918

 < 0.001

98.7%

Trial duration (week)

 ≥ 12

1

-1.10 (-1.49, -0.70)

 < 0.001

-

-

0.269

 <12

4

0.24 (-2.10, 2.59)

0.838

 < 0.001

95.3%

Intervention dose (g/day)

 ≥ 3

4

0.02 (-2.31, 2.35)

0.986

 < 0.001

99.0%

0.513

 <3

1

-3.63 (-14.30, 7.04)

0.505

-

-

Baselin BMI (kg/m²)

 Obese (> 30)

4

0.02 (-2.31, 2.35)

0.986

 < 0.001

99.0%

0.513

 Overweight (25–29.9)

1

-3.63 (-14.30, 7.04)

0.505

-

-

Sex

 Male

2

-0.59 (-1.32, 0.13)

0.110

0.708

0.0%

0.132

 Both

2

1.84 (-1.57, 5.26)

0.290

0.268

18.4%

 Female

1

-1.10 (-1.49, -0.70)

 < 0.001

-

-

Health status

 T2DM

2

-1.10 (-1.49, -0.71)

 < 0.001

0.643

0.0%

 < 0.001

 Hyperlipidemic

2

-0.59 (-1.32, 0.13)

0.110

0.708

0.0%

 Hypertension

1

2.40 (2.25, 2.54)

 < 0.001

-

-

Subgroup analyses of CLA on serum leptin (ng/ml)

 Overall effect

5

-1.69 (-1.80, -1.58)

 < 0.001

0.451

0.0%

Trial duration (week)

 ≥ 12

3

-1.08 (-1.87, -0.30)

0.007

0.906

0.0%

0.208

 <12

2

-1.81 (-2.63, -0.99)

 < 0.001

0.282

13.8%

Intervention dose (g/day)

 ≥ 3

4

-1.68 (-1.79, -1.57)

 < 0.001

0.475

0.0%

0.278

 <3

1

-3.34 (-6.32, -0.35)

0.028

Baselin BMI (kg/m²)

 Obese (> 30)

4

-1.68 (-1.79, -1.57)

 < 0.001

0.475

0.0%

0.278

 Overweight (25–29.9)

1

-3.34 (-6.32, -0.35)

0.028

Sex

 Male

2

-1.35 (-2.94, 0.24)

0.097

0.812

0.0%

0.422

 Both

2

-1.81 (-2.63, -0.99)

 < 0.001

0.282

13.8%

 Female

1

-1.00 (-1.90, -0.09)

0.030

-

-

Health status

 Metabolic syndrome

2

-1.35 (-2.94, 0.24)

0.097

0.812

0.0%

0.913

 T2DM

2

-1.72 (-3.83, 0.39)

0.111

0.141

53.8%

 Hypertension

1

-1.70 (-1.81, -1.58)

 < 0.001

-

-

Subgroup analyses of CLA on serum MDA (mmol/l)

 Overall effect

3

-0.08 (-0.80, 0.62)

0.809

0.001

85.7%

Subgroup analyses of CLA on serum ALT (IU/L)

 Overall effect

4

0.48 (-5.11, 6.07)

0.866

0.007

75.5%

Subgroup analyses of CLA on serum AST (IU/L)

 Overall effect

4

2.54 (0.06, 5.01)

0.044

0.046

62.4%