From: Systematic review of the relation between smokeless tobacco and cancer in Europe and North America
 |  |  |  | Heterogeneity | ||
---|---|---|---|---|---|---|
Type of ST (region)a | Adjustments/restrictionsb | Number of estimates (RR/OR ids)c | Random-effects RR/OR (95% CI) | χ2 | I2 | P(χ2) |
Any (USA)d | Overall data | 5 (4, 5, 6, 9, 19) | 0.86 (0.59–1.25) | 17.3 | 76.9 | 0.002 |
 | Smoking-adjusted | 5 (4, 5, 6, 9, 19) | 0.86 (0.59–1.25) | 17.3 | 76.9 | 0.002 |
 | Never smokers | 4 (4, 5, 6, 9) | 1.14 (0.99–1.33) | 3.1 | 2.1 | 0.382 |