Table 2. Stratified analyses of dietary choline and betaine consumption and cancer risk.
| Group | Choline consumption only |
Betaine consumption only |
Choline plus betaine consumption |
||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. of comparisons | Summary OR(95%CI) | Heterogeneity | No. of comparisons | Summary OR(95%CI) | Heterogeneity | No. of comparisons | Summary OR(95%CI) | Heterogeneity | |||||||
| χ2 | P | I2(%) | χ2 | P | I2(%) | χ2 | P | I2(%) | |||||||
| Total | 14 | 0.82(0.69–0.96) | 65.56 | < 0.001 | 80.2 | 14 | 0.86(0.76–0.97) | 38.02 | <0.001 | 65.8 | 5 | 0.60(0.40–0.90) | 22.23 | <0.001 | 82.0 |
| Design | |||||||||||||||
| Cohort | 6 | 1.00(0.92–1.10) | 5.68 | 0.339 | 11.9 | 6 | 0.98(0.90–1.06) | 2.64 | 0.755 | 0 | 1 | 0.99(0.75–1.31) | 0 | — | — |
| Case-control | 8 | 0.71(0.52–0.97) | 47.07 | <0.001 | 85.1 | 8 | 0.75(0.62–0.92) | 20.09 | 0.005 | 65.1 | 4 | 0.52(0.34–0.80) | 12.17 | 0.007 | 75.3 |
| Population based | 3 | 1.11(0.83–1.49) | 3.88 | 0.144 | 48.4 | 3 | 0.96(0.75-1.23) | — | 0.185 | 40.7 | 0 | — | — | — | — |
| Hospital based | 4 | 0.52(0.30–0.90) | 28.75 | <0.001 | 89.6 | 4 | 0.60(0.49–0.75) | 4.87 | 0.181 | 38.4 | 3 | 0.43(0.33–0.55) | 0.07 | 0.965 | 0 |
| Mixed based | 1 | 0.54(0.37–0.79) | 0 | — | — | 1 | 0.92(0.65–1.30) | 0 | — | — | 1 | 0.91(0.65–1.28) | 0 | — | — |
| Location | |||||||||||||||
| Non-China | 10 | 0.99(0.91–1.08) | 11.55 | 0.24 | 22.1 | 10 | 0.93(0.83–1.03) | 18.49 | 0.030 | 51.3 | 1 | 0.99(0.75–1.31) | 0 | — | — |
| China | 4 | 0.45(0.36–0.55) | 2.41 | 0.492 | 0 | 4 | 0.61(0.44–0.85) | 7.60 | 0.055 | 60.5 | 4 | 0.52(0.34–0.80) | 12.17 | 0.007 | 75.3 |
| Cancer type | |||||||||||||||
| Breast cancer | 5 | 0.73(0.52–1.01) | 32.51 | <0.001 | 87.7 | 5 | 0.86(0.71–1.04) | 11.24 | 0.024 | 64.4 | 2 | 0.42(0.30–0.59) | 0.04 | 0.845 | 0 |
| Other | 9 | 0.86(0.70–1.06) | 31.42 | <0.001 | 74.5 | 9 | 0.86(0.73–1.02) | 22.43 | 0.004 | 64.3 | 3 | 0.74(0.46–1.20) | 12.29 | 0.002 | 83.7 |
| Publication year | |||||||||||||||
| ≤2010 | 7 | 1.02(0.92–1.14) | 8.54 | 0.201 | 29.8 | 7 | 0.97(0.90–1.04) | 3.62 | 0.727 | 0 | 1 | 0.99(0.75–1.31) | 0 | — | — |
| >2010 | 7 | 0.61(0.44–0.84) | 32.7 | <0.001 | 81.7 | 7 | 0.72(0.57–0.90) | 16.02 | 0.014s | 62.5 | 4 | 0.52(0.34–0.80) | 12.17 | 0.007 | 75.3 |
| Sex | |||||||||||||||
| M only | 2 | 0.97(0.80–1.17) | 0 | 0.966 | 0 | 2 | 1.04(0.77–1.39) | 1.68 | 0.194 | 65.8 | 0 | — | — | — | — |
| F only | 7 | 0.78(0.61–0.99) | 33.29 | <0.001 | 82.0 | 7 | 0.88(0.76–1.02) | 11.96 | 0.063 | 49.8 | 3 | 0.57(0.30–1.09) | 14.24 | 0.001 | 86.0 |
| M and F | 5 | 0.81(0.55–1.20) | 29.71 | <0.001 | 86.5 | 5 | 0.78(0.62–1.00) | 12.86 | 0.012 | 68.9 | 2 | 0.64(0.31–1.30) | 7.85 | 0.005 | 87.3 |
| Quality score | |||||||||||||||
| <7 stars | 4 | 1.03(0.84–1.26) | 5.61 | 0.132 | 46.5 | 4 | 0.87(0.69–1.10) | 8.64 | 0.034 | 65.3 | 0 | — | — | — | — |
| ≥7 stars | 10 | 0.73(0.58–0.91) | 59.27 | <0.001 | 84.8 | 10 | 0.85(0.73–0.99) | 25.55 | 0.002 | 64.8 | 5 | 0.60(0.40–0.90) | 22.23 | <0.001 | 82.0 |