Table 1.
Baseline characteristics of all the studies included in the meta-analysis
| First Author, Year, Country | Study design | Age (years) | No. of Cases /Participants | Dietary assessment | Exposure details | Contrast (Highest vs. lowest) | RR (95% CI) (Highest vs. lowest) | Adjustments | NOS |
|---|---|---|---|---|---|---|---|---|---|
| Qin,2015, USA | PB-CC | Cases:57.5 Control:54.5 |
406/1015 | Validated 110-item FFQ | Total fiber | ≥10.9 vs. ≤6.5 g/d | 0.79 (0.53,1.17) | Age, education, region, total energy intake, parity, oral contraceptive use, menopause status, tubal ligation and family history of breast/ovarian cancer, alcohol. | 7 |
| Hedelin,2011, Sweden | Cohort | 30–49 at entry |
163/47140 | Validated 80-item FFQ | Total fiber Cereal fiber Vegetable fiber |
2.5–10 vs. ≤1.82 g/d 1.5–5.7 vs. ≤0.90 g/d 2.5–10 vs. ≤1.82 g/d |
0.82 (0.50,1.35) 1.17 (0.74,1.87) 1.02 (0.63,1.64) |
Age, oral contraceptives, age at menarche, parity, hormone replacement therapy, and intake of total energy intake, alcohol, saturated fat, meat, and fish. | 8 |
| Nagle,2011, Australia | PB-CC | Cases:57.6 Control:56.3 |
1366/2780 | 136-item FFQ | Total fiber | 38–77 vs. 10–27 g/d | 0.78 (0.62,0.98) | Age, oral contraceptive use, level of post school education, parity, BMI, menopausal status, energy intake. | 8 |
| Silvera,2007, USA | Cohort | 59.4 ± 7.2 | 264/49613 | Validated 86-item FFQ |
Total fiber Soluble fiber Insoluble fiber Cereal fiber Vegetable fiber Fruit fiber |
> 24.0 vs. < 15.6 g/d > 7.4 vs. < 4.4 g/d > 5.1 vs. < 2.8 g/d > 5.2 vs. < 2.6 g/d > 10.1 vs. < 5.5 g/d > 5.8 vs. < 2.2 g/d |
0.77 (0.52,1.14) 0.79 (0.51,1.23) 0.72 (0.47,1.10) 1.09 (0.71,1.70) 0.94 (0.63,1.40) 0.76 (0.51,1.12) |
Age, BMI, alcohol, hormone replacement therapy, use of oral contraceptives, parity, age at Menarche, menopausal status, total energy intake, physical activity, study center, treatment allocation. |
8 |
| Pan,2004, Canada | PB-CC | Cases:55.1 Control:55.2 |
442/2577 | Validated 69-item FFQ |
Total fiber | Q4 vs. Q1 | 0.91 (0.66,1.25) | 10-year age group, province of residence, education, alcohol consumption, cigarette pack-years, BMI, total caloric intake, recreational Physical activity, number of live births, menstruation years, menopause status. |
7 |
| McCann,2003, USA | PB-CC | 40–85 | 124/820 | FFQ | Total fiber | > 34 vs. < 19 g/d | 0.43 (0.20,0.94) | Age, education, total months menstruating, difficulty becoming pregnant, oral contraceptive use, menopausal status, total energy | 6 |
| Zhang,2004, Australia | HB-CC | < 75 | 254/906 | Validated 120-item FFQ | Insoluble fiber | ≥15.3 vs. ≤9.7 g/d | 0.36 (0.21,0.62) | Age, education, family income, BMI, total energy intake, smoking, alcohol, ovarian cancer in first degree relatives, parity, menopausal status, oral contraceptive use. | 6 |
| Salazar-Martinez,2002, Mexico | HB-CC | 20–79 | 84/713 | Validated 116-item FFQ |
Total fiber | ≥24 vs. ≤ 13 g/d | 1.15(0.65,2.05) | Age, total energy intake, number of live births, recent changes in weight, physical activity, diabetes. | 6 |
| Goodman, 2002, USA | PB-CC | 54.8 | 558/1165 | 256-item FFQ | Total fiber | ≥29.4 vs. ≤ 15.3 g/d | 1.01 (0.63,1.63) | Age, ethnicity, study center, education, use of oral contraceptives, parity, tubal ligation, energy intake. | 7 |
| Pelucchi,2001, Italy | HB-CC | 18–79 | 1031/3442 | Validated 78-item FFQ |
Total fiber Insoluble fiber Vegetable fiber Fruit fiber Grain fiber |
Q5 vs. Q1 Q5 vs. Q1 Q5 vs. Q1 Q5 vs. Q1 Q5 vs. Q1 |
0.68 (0.53,0.88) 0.70 (0.54,0.89) 0.59 (0.46,0.77) 0.96 (0.75,1.22) 1.32 (1.03,1.71) |
Age, center, education, occupational physical activity, parity, oral contraceptive use, family history of ovarian and/or breast cancer in first-degree relatives, menopausal status, total energy intake |
6 |
| McCann,2001, USA, | HB-CC | 20–87 | 496/1921 | 44-item FFQ | Total fiber | ≥30 vs. ≤16 g/d | 0.57 (0.38,0.87) | Age, education, region of residence, regularity of menstruation, family history of ovarian cancer, parity, age at menarche, oral contraceptive use, total energy intake | 6 |
| Kushi,1999, USA | Cohort | 55–69 | 139/29083 | Validated 126-item FFQ |
Total fiber | > 23.6 vs. < 16.3 g/d | 1.01 (0.61,1.68) | Age, total energy intake, number of live births, age at menopause, family history of ovarian cancer in a first-degree relative, hysterectomy/unilateral oophorectomy status, waist-to-hip ratio, level of physical activity, cigarette smoking, and educational level. | 7 |
| Risch,1994, Canada | PB-CC | 35–79 | 450/1014 | 200-item FFQ | Total fiber Vegetable fiber Fruit fiber Cereal fiber |
For 10 g/d increase | 0.82 (0.71,0.94) 0.63 (0.49,0.80) 1.03 (1.75,1.43) 0.88 (0.70,1.10) |
Age, number of full-term pregnancies, oral contraceptive use, total dally calories, saturated tat/total fat. | 6 |
Abbreviations: RR relative risk, CI confidence interval, PB-CC population-based case-control, HB-CC hospital-based case-control, NOS Newcastle–Ottawa Quality Assessment Scale, FFQ food frequency questionnaire, BMI body mass index