No in each group | No of deaths | ||||
---|---|---|---|---|---|
Study | Intervention | Control | Intervention | Control | Relative risk (95% CI) |
*With the fixed effects model the pooled results were 0.98 (95% CI 0.95 to 1.02). | |||||
Erfurt County3 | 41532 | 102348 | 3143 | 8038 | 0.96 (0.93 to 1.00) |
Czech study 16 | 3171 | 3174 | 341 | 293 | 1.16 (1.00 to 1.35) |
Mayo Lung Project4 | 4618 | 4593 | 688 | 665 | 1.03 (0.93 to 1.14) |
Kaiser Permanente18 | 5156 | 5557 | 585 | 643 | 0.98 (0.88 to 1.09) |
Total | 54477 | 115672 | 4757 | 9639 | 1.01 (0.94 to 1.08)* |