Table 3.
Exposure–response relationship between use of cellular phones and risk of tumors.
| Factor | All | Hardell et al.’s Studies | INTERPHONE-Related Studies | Other Groups | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| No. | OR (95% CI) | I2 | No. | OR (95% CI) | I2 | No. | OR (95% CI) | I2 | No. | OR (95% CI) | I2 | ||
| Time since first use or latency (years) | <5 | 25 | 0.97 (0.86 to 1.09) | 39.0 | 10 | 1.05 (0.92 to 1.19) | 0.0 | 8 | 0.78 (0.64 to 0.94) | 36.2 | 8 | 1.10 (0.92 to 1.32) | 14.6 |
| 5–9 | 23 | 1.00 (0.86 to 1.16) | 51.0 | 10 | 1.20 (0.88 to 1.63) | 44.4 | 8 | 0.80 (0.70 to 0.92) | 13.7 | 5 | 1.19 (0.99 to 1.44) | 0.0 | |
| ≥10 | 18 | 1.29 (0.90 to 1.85) | 87.8 | 5 | 1.62 (1.03 to 2.57) * | 39.9 | 8 | 0.99 (0.79 to 1.24) | 25.3 | 5 | 1.57 (0.72 to 3.42) | 93.3 | |
| Cumulative or lifetime use (years) | <5 | 14 | 0.81 (0.74 to 0.90) | 19.6 | n.a. | 9 | 0.77 (0.69 to 0.86) | 15.8 | 5 | 0.99 (0.81 to 1.21) | 0.0 | ||
| 5–9 | 14 | 0.89 (0.78 to 1.01) | 22.9 | 9 | 0.83 (0.73 to 0.94) | 0.0 | 5 | 1.04 (0.75 to 1.46) | 54.4 | ||||
| ≥10 | 9 | 1.04 (0.69 to 1.59) | 36.9 | 5 | 0.92 (0.54 to 1.59) | 0.0 | 5 | 1.15 (0.61 to 2.18) | 77.1 | ||||
| Cumulative call time (hours) | <300 | 26 | 0.99 (0.90 to 1.08) | 0.0 | 9 | 1.08 (0.94 to 1.23) | 9.2 | 9 | 0.78 (0.66 to 0.93) | 0.0 | 8 | 1.05 (0.89 to 1.24) | 0.0 |
| 300–1000 | 7 | 1.14 (0.91 to 1.41) | 40.9 | 1 | 1.00 (0.40 to 2.60) | 2 | 1.07 (0.77 to 1.49) | 0.0 | 4 | 1.21 (0.79 to 1.84) | 40.9 | ||
| >1000 | 8 | 1.60 (1.12 to 2.30) * | 74.5 | 2 | 3.65 (1.69 to 7.85) * | 0.0 | 4 | 1.25 (0.96 to 1.62) | 23.7 | 2 | 1.73 (0.66 to 4.48) | 91.8 | |
| Cumulative number of calls | <1000 | 7 | 1.07 (0.87 to 1.32) | 9.6 | n.a. | 2 | 0.70 (0.38 to 1.29) | 0.0 | 5 | 1.13 (0.92 to 1.39) | 0.0 | ||
| 1000–7000 | 5 | 1.00 (0.69 to 1.43) | 51.6 | n.a. | n.a. | 5 | 1.00 (0.69 to 1.43) | 51.6 | |||||
| >7000 | 10 | 1.14 (0.39 to 3.32) | 98.6 | n.a. | 5 | 0.85 (0.56 to 1.29) | 55.1 | 5 | 1.68 (0.36 to 7.94) | 99.0 | |||
No.,number of studies; n.a., not available. ‘*’ indicates that cellular phone use statistically significantly increases the risk of tumor.