Table 2.
Association between obesity and the odds of breast cancer development by geographic location
| Number of Studies | I2 | P2 | OR (95%CI) | P-between* | |
|---|---|---|---|---|---|
| Association between obesity in pre-menopause and breast cancer risk | |||||
| Asia | 22 | 76.71 | 0.0001 | 1 (0.87–1.15) | 0.0001 |
| Europe | 8 | 44.8 | 0.081 | 0.88 (0.79–0.98) | |
| Africa | 2 | 69.7 | 0.069 | 1.07(0.42–2.69) | |
| North America | 15 | 60.5 | 0.0001 | 0.84 (0.71–1) | |
| South America | 2 | 0.0 | 0.896 | 0.97 (0.87–1.09) | |
| Oceania | - | - | - | - | |
| Association between obesity in post-menopause and breast cancer risk | |||||
| Asia | 27 | 94.7 | 0.0001 | 1.49 (1.32–1.69) | 0.0001 |
| Europe | 10 | 85 | 0.0001 | 1.10 (0.97–1.25) | |
| Africa | 2 | 0.0 | 0.92 | 1.69 (0.98–2.92) | |
| North America | 23 | 75.5 | 0.0001 | 1.21 (1.07–1.36) | |
| South Africa | 3 | 70.8 | 0.033 | 1.21 (0.87–1.68) | |
| Oceania | 1 | 0.0 | - | 1.04 (0.83–1.30) | |
| Association between obesity and breast cancer risk regardless of menstrual status | |||||
| Asia | 14 | 86.1 | 0.0001 | 1.45 (1.22–1.73) | 0.0001 |
| Europe | 3 | 0.0 | 0.87 | 1.21 (1.01–1.46) | |
| Africa | 2 | 39.8 | 0.197 | 1.24 (1.04–1.48) | |
| North America | 11 | 83.6 | 0.0001 | 1.24 (1.05–1.46) | |
| South America | 3 | 92.5 | 0.0001 | 1.03 (0.37–2.54) | |
| Oceania | 1 | 0.0 | 3.5 (1.3–9.41) | ||
*P-between: Heterogeneity between groups, P2: Heterogeneity between studies in group, I2:percentage of variation acrros studies due to heterogeneity