Table 1.
Summary estimates of the dose–response association between coffee consumption and prostate cancer risk
| No. of studies | Pooled RR (95% CI)a | Heterogeneity |
||||
|---|---|---|---|---|---|---|
| Q | df | P-value | I2 (%) | |||
| Nonaggressive PCa | ||||||
| Low-grade | 6 | 0.97 (0.92–1.03) | 4.5 | 5 | 0.48 | 0 |
| Case–control studies | 3 | 1.07 (0.95–1.20) | 0.3 | 2 | 0.87 | 0 |
| Cohort studies | 3 | 0.95 (0.89–1.01) | 1.3 | 2 | 0.48 | 0 |
| Localized | 6 | 0.97 (0.94–0.99) | 3.6 | 5 | 0.61 | 0 |
| Case–control studies | 2 | 1.02 (0.89–1.17) | 0.1 | 1 | 0.76 | 0 |
| Cohort studies | 4 | 0.97 (0.95–0.99) | 2.9 | 3 | 0.41 | 0 |
| Aggressive PCa | ||||||
| High-grade | 6 | 0.89 (0.78–1.00) | 6.8 | 5 | 0.24 | 26 |
| Case–control studies | 3 | 0.91 (0.75–1.15) | 2.8 | 2 | 0.25 | 29 |
| Cohort studies | 3 | 0.85 (0.69–1.04) | 3.8 | 2 | 0.15 | 48 |
| Advanced | 6 | 0.95 (0.85–1.06) | 12.5 | 5 | 0.03 | 60 |
| Case–control studies | 2 | 1.08 (0.89–1.32) | 0.5 | 1 | 0.50 | 0 |
| Cohort studies | 4 | 0.91 (0.80–1.05) | 12.5 | 3 | 0.01 | 73 |
| Fatal PCa | 4 | 0.89 (0.82–0.97) | 2.0 | 3 | 0.58 | 0 |
| Case–control studies | 1 | 0.97 (0.73–1.28) | — | — | — | — |
| Cohort studies | 3 | 0.88 (0.81–0.97) | 1.6 | 2 | 0.45 | 0 |
aFor every 3 cups/day increase in coffee consumption.
PCa, prostate cancer; RR, relative risk; CI, confidence interval; df, degrees of freedom.