Table 2.
Summary risk estimates of the association between tea consumption and thyroid cancer risk
| Subgroups | No. (cases) | No. studies | Risk estimate (95% CI) | Heterogeneity test I2 (%) P-value | |
|---|---|---|---|---|---|
| All studies | 2955 | 14 | 0.774 (0.619-0.967) | 36.5 | 0.084 |
| Study design | |||||
| Prospective | 159 | 2 | 0.877 (0.560-1.374) | 0.0 | 0.701 |
| Case-control | 2796 | 12 | 0.747 (0.574-0.972) | 45.7 | 0.042 |
| Geographic locations | |||||
| Europe | 1996 | 8 | 0.805 (0.575-1.127) | 51.3 | 0.045 |
| America | 593 | 3 | 0.602 (0.390-0.928) | 27.9 | 0.250 |
| Asia | 366 | 3 | 0.888 (0.580-1.361) | 0.0 | 0.915 |
| Sources of control | |||||
| Population-based | 1096 | 6 | 0.761 (0.580-0.998) | 11.1 | 0.344 |
| Hospital-based | 1700 | 6 | 0.699 (0.431-1.133) | 64.2 | 0.016 |