Table 2 Subgroup analysis of dietary fiber intake and ovarian cancer risk
From: Dietary fiber intake and reduced risk of ovarian cancer: a meta-analysis
Subgroup | Studies, n | RR (95% CI) | I2 (%) | P a | P b |
|---|---|---|---|---|---|
Total | 11 | 0.78 (0.70,0.88) | 4.20 | 0.40 | Â |
Study design | |||||
 Case-control | 8 | 0.77 (0.66,0.90) | 25 | 0.23 | 0.17 |
 Cohort | 3 | 0.84 (0.65,1.10) | 0 | 0.70 |  |
Type of control subjects | |||||
 Population-based | 8 | 0.82 (0.72,0.94) | 0 | 0.69 | 0.16 |
 Hospital-based | 3 | 0.72 (0.52,0.99) | 48.20 | 0.15 |  |
Geographic location | |||||
 North America | 7 | 0.79 (0.66,0.95) | 19.40 | 0.28 | 0.87 |
 Others | 4 | 0.77 (0.66,0.89) | 0 | 0.41 |  |
No. of cases | |||||
 < 300 | 5 | 0.83 (0.65,1.07) | 15.40 | 0.32 | 0.16 |
 ≥ 300 | 6 | 0.77 (0.67,0.87) | 5.10 | 0.38 |  |
Study quality | |||||
 NOS < 7 | 4 | 0.68 (0.50,0.91) | 42.90 | 0.15 | 0.09 |
 NOS ≥7 | 7 | 0.84 (0.73,0.96) | 0 | 0.92 |  |
Validation FFQ | |||||
 Yes | 7 | 0.81 (0.70,0.93) | 0 | 0.60 | 0.59 |
 No | 4 | 0.72 (0.54,0.94) | 43.00 | 0.15 |  |
Fiber type | |||||
 Vegetable fiber | 3 | 0.80 (0.55,1.16) | 66.90 | 0.05 |  |
 Fruit fiber | 2 | 0.90 (0.73,1.11) | 0 | 0.32 |  |
 Cereal fiber | 3 | 1.24 (1.02,1.51) | 0 | 0.73 |  |
Fiber source | |||||
 Soluble fiber | 1 | 0.79 (0.51,1.23) | – | – |  |
 Insoluble fiber | 3 | 0.60 (0.42,0.86) | 61.00 | 0.08 |  |
Adjustments | |||||
BMI | |||||
 Yes | 3 | 0.81 (0.69,0.96) | 0 | 0.71 |  |
 No | 8 | 0.77 (0.64,0.92) | 25.40 | 0.23 |  |
Parity | |||||
 Yes | 10 | 0.79 (0.70,0.89) | 0 | 0.52 |  |
 No | 1 | 0.43 (0.20,0.93) | – | – |  |
Oral contraceptive use | |||||
 Yes | 8 | 0.74 (0.65,0.84) | 0 | 0.54 |  |
 No | 3 | 0.97 (0.76,1.24) | 0 | 0.77 |  |
physical activity | |||||
 Yes | 6 | 0.80 (0.70,0.91) | 0 | 0.46 |  |
 No | 5 | 0.73 (0.57,0.94) | 24.80 | 0.26 |  |
Menopausal status | |||||
 Yes | 6 | 0.76 (0.67,0.86) | 0 | 0.53 |  |
 No | 5 | 0.86 (0.66,1.11) | 28.70 | 0.23 |  |