Table 3.
Subgroup analysis of dietary fiber intake in glycaemic control.
| Fasting plasma glucose | Fasting plasma insulin | |||||||
|---|---|---|---|---|---|---|---|---|
| No. of studies |
ES (95% CI) |
Heterogeneity | No. of studies | ES (95% CI) | Heterogeneity | |||
| P | P | |||||||
| Country | ||||||||
| China | 16 | −0.69 (−0.92, −0.45) |
98.20 | <0.001 | 14 | −1.202 (−1.615, −0.789) |
56.36 | 0.005 |
| Iran | 3 | −0.66 (−3.41, 2.09) |
87.44 | <0.001 | 2 | −1.172 (−2.491, 0.147) |
68.96 | 0.073 |
| USA | 2 | −0.48 (−1.15, 0.18) |
90.54 | 0.001 | 1 | ~ | ~ | ~ |
| Other | 6 | −0.26 (−0.61, 0.09) |
75.32 | 0.001 | 1 | ~ | ~ | ~ |
| Study population | ||||||||
| Diabetics | 14 | −1.52 (−2.08, −0.97) |
98.46 | <0.001 | 9 | −1.619 (−2.492, −0.746) |
68.01 | 0.002 |
| Dyslipidemia | 2 | −0.04 (−0.09, 0.01) |
0 | 0.587 | 1 | ~ | ~ | ~ |
| MS | 1 | ~ | ~ | ~ | 1 | ~ | ~ | ~ |
| Other | 10 | −0.13 (−0. 21, −0.05) |
62.55 | 0.004 | 7 | −0.980 (−1.439, −0.522) |
46.17 | 0.084 |
| Type of effect size | ||||||||
| WMD | 13 | −0.17 (−0.28, −0.06) |
80.90 | <0.001 | 9 | −1.303 (−1.616, −0.991) |
38.04 | 0.115 |
| SMD | 2 | −0.42 (−0.70, −0.13) |
71.58 | 0.061 | 3 | −0.588 (−0.835, −0.341) |
0 | 0.397 |
| MD | 12 | −1.20 (−1.64, −0.77) |
98.63 | <0.001 | 6 | −1.947 (−2.917, −0.976) |
43.95 | 0.112 |
| Type of intervention | ||||||||
| RS | 6 | −0.094 (−0.185, −0.004) |
61.68 | 0.023 | 5 | −1.618 (−2.503, −0.732) |
69.02 | 0.012 |
| β-glucan | 4 | −0.056 (−0.102, −0.011) |
49.62 | 0.114 | 3 | 0.186 (−2.303, 2.675) |
34.19 | 0.219 |
| ITF | 5 | −2.807 (−3.741, −1.874) |
99.48 | <0.001 | 5 | −1.277 (−1.672, −0.881) |
0 | 0.811 |
| Others | 12 | −0.499 (−0.831, −0.168) |
83.54 | <0.001 | 5 | −0.961 (−1.872, −0.051) |
69.94 | 0.010 |
| Sample size | ||||||||
| n <300 | 5 | −0.628 (−1.181, −0.076) |
73.66 | 0.004 | 5 | −1.701 (−2.766, −0.636) |
50.27 | 0.09 |
| 300 ≤ n <600 | 13 | −0.89 (−1.23, −0.54) |
98.48 | <0.001 | 9 | −1.293 (−1.934, −0.651) |
54.96 | 0.023 |
| n ≥ 600 | 9 | −0.26 (−0.41, −0.13) |
86.34 | <0.001 | 4 | −1.094 (−1.689, −0.500) |
74.70 | 0.008 |
| Dosage | ||||||||
| n <5 | 6 | −0.103 (−0.212, 0.006) |
64.92 | 0.014 | 3 | −0.186 (−2.306, 2.675) |
34.19 | 0.219 |
| 5 ≤ n <10 | 7 | −2.843 (−3.843, −1.843) |
99.23 | <0.001 | 6 | −1.257 (−2.048, −0.465) |
68.50 | 0.007 |
| n ≥ 10 | 12 | −0.161 (−0.256, −0.067) |
74.06 | <0.001 | 8 | −1.448 (−2.029, −0.867) |
56.31 | 0.025 |
| Duration | ||||||||
| n <7 | 8 | −0.086 (−0.140, −0.032) |
52.86 | 0.038 | 6 | −0.902 (−1.218, −0.586) |
0 | 0.457 |
| 7 ≤ n <11 | 13 | −1.363 (−1.856, −0.869) |
98.55 | <0.001 | 11 | −1.452 (−2.037, −0.867) |
67.78 | 0.001 |
| n ≥ 12 | 5 | −0.175 (−0.598, 0.249) |
797.52 | 0.001 | 1 | ~ | ~ | ~ |
| HOMA-IR | HbA1c | |||||||
| Country | ||||||||
| China | 9 | −0.490 (−0.611, −0.369) |
21.31 | 0.254 | 10 | −0.442 (−0.627, −0.258) |
91.51 | <0.001 |
| Iran | 2 | −0.174 (−0.375, 0.027) |
0 | 0.451 | 2 | −0.293 (−0.910, 0.324) |
85.60 | 0.008 |
| USA | 1 | ~ | ~ | ~ | 1 | ~ | ~ | ~ |
| Other | 3 | −0.245 (−0.844, 0.354) |
67.05 | 0.048 | 5 | −0.289 (−0.447, −0.130) |
56.37 | 0.057 |
| Study population | ||||||||
| Diabetics | 9 | −0.522 (−0.774, 0.270) |
54.78 | 0.024 | 13 | −0.393 (−0.535, −0.251) |
89.31 | <0.001 |
| Dyslipidemia | 0 | ~ | ~ | ~ | 0 | ~ | ~ | ~ |
| MS | 1 | ~ | ~ | ~ | 1 | ~ | ~ | ~ |
| Other | 5 | −0.348 (−0.610, −0.086) |
56.80 | 0.055 | 4 | −0.297 (−0.447, −0.146) |
32.17 | 0.219 |
| Type of effect size | ||||||||
| WMD | 6 | −0.345 (−0.463, −0.228) |
51.25 | 0.068 | 8 | −0.361 (−0.549, −0.173) |
88.13 | <0.001 |
| SMD | 3 | −0.618 (−0.874, −0.362) |
0 | 0.829 | 2 | −0.596 (−0.779, −0.412) |
43.81 | 0.182 |
| MD | 6 | −0.458 (−0.899, −0.017) |
63.33 | 0.018 | 8 | −0.345 (−0.489, −0.202) |
71.82 | 0.001 |
| Type of intervention | ||||||||
| RS | 6 | −0.311 (−0.450, −0.173) |
0 | 0.827 | 5 | −0.225 (−0.384, −0.065) |
81.69 | <0.001 |
| β-glucan | 0 | ~ | ~ | ~ | 1 | ~ | ~ | ~ |
| ITF | 3 | −0.648 (−0.882, −0.415) |
0 | 0.446 | 3 | −0.589 (−0.730, −0.448) |
38.07 | 0.199 |
| Others | 6 | −0.507 (−0.928, −0.086) |
72.86 | 0.002 | 9 | −0.408 (−0.587, −0.229) |
77.90 | <0.001 |
| Sample size | ||||||||
| n <300 | 6 | −0.347 (−0.506, −0.189) |
48.15 | 0.086 | 6 | −0.388 (−0.649, −0.128) |
89.89 | <0.001 |
| 300 ≤ n <600 | 5 | −0.353 (−0.567, −0.139) |
41.90 | 0.142 | 7 | −0.312 (−0.466, −0.157) |
80.40 | <0.001 |
| n ≥ 600 | 4 | −0.483 (−0.820, −0.147) |
74.96 | 0.007 | 5 | −0.493 (−0.726, −0.260) |
62.83 | 0.029 |
| Dosage | ||||||||
| n <5 | 0 | ~ | ~ | ~ | 1 | ~ | ~ | ~ |
| 5 ≤ n <10 | 6 | −0.653 (−0.829, −0.477) |
0 | 0.510 | 6 | −0.631 (−0.740, −0.521) |
8.87 | 0.359 |
| n ≥ 10 | 7 | −0.324 (−0.462, −0.186) |
1.02 | 0.416 | 8 | −0.304 (−0.456, −0.151) |
82.34 | <0.001 |
| Duration | ||||||||
| n <7 | 3 | −0.298 (−0.451, −0.144) |
0 | 0.398 | 4 | −0.196 (−0.380, −0.013) |
73.43 | 0.010 |
| 7 ≤ n <11 | 10 | −0.540 (−0.760, −0.320) |
54.06 | 0.021 | 9 | −0.474 (−0.682, −0.266) |
85.80 | <0.001 |
| n ≥12 | 2 | −0.374 (−1.762, −1.013) |
64.43 | 0.094 | 4 | −0.379 (−0.645, −0.113) |
79.96 | 0.002 |
ES, effect size; MS, metabolic syndrome; RS, resistant starch; ITF, inulin-type fructans; WMD, weight mean difference; SMD, standardized mean difference; MD, mean difference.