TABLE 2.
Subgroup analyses for the association of dietary fiber intake with risk of UC and CD1
| Variables | Subgroups | Number of effect sizes | Pooled RR (95% CI) | I 2, % | |
|---|---|---|---|---|---|
| Risk of UC | Age | Adult2 | 3 | 0.97 (0.74, 1.28) | 37.2 |
| Adult + elderly3 | 4 | 1.28 (0.91, 1.79) | 0.0 | ||
| Sex | Female | 2 | 0.88 (0.65, 1.19) | 0.0 | |
| Male + female | 5 | 1.34 (0.99, 1.80) | 0.0 | ||
| Study location | USA | 3 | 0.97 (0.74, 1.28) | 37.2 | |
| Other | 4 | 1.28 (0.91, 1.79) | 0.0 | ||
| Sample size | n <10,000 | 4 | 1.41 (1.00, 1.97) | 0.0 | |
| n ≥10,000 | 3 | 0.92 (0.70, 1.20) | 0.0 | ||
| Study type | Cohort | 4 | 1.00 (0.77, 1.28) | 10.1 | |
| Nested case-control | 3 | 1.34 (0.91, 2.00) | 0.0 | ||
| Age | Adult | 3 | 0.58 (0.44, 0.76) | 0.0 | |
| Adult + elderly | 3 | 0.62 (0.39, 0.98) | 0.0 | ||
| Risk of CD | Sex | Female | 2 | 0.58 (0.40, 0.83) | 0.0 |
| Male + female | 4 | 0.59 (0.43, 0.81) | 0.0 | ||
| Study location | USA | 3 | 0.58 (0.44, 0.76) | 0.0 | |
| Other | 3 | 0.62 (0.39, 0.98) | 0.0 | ||
| Sample size | n <10,000 | 4 | 0.59 (0.43, 0.81) | 0.0 | |
| n ≥10,000 | 2 | 0.58 (0.40, 0.83) | 0.0 | ||
| Study type | Cohort | 3 | 0.58 (0.44, 0.76) | 0.0 | |
| Nested case-control | 3 | 0.62 (0.39, 0.98) | 0.0 | ||
1
CD, Crohn disease; UC, ulcerative colitis.
2
Studies done on people aged 20–65 y.
3
Studies done on adults and elderly participants (≥20 y).