Case-control comparisons of indices for mobile phone use
| Control | Case | p for trend | Odds ratio* 95% CI) | |
|---|---|---|---|---|
| *Adjusted for education and marital status. | ||||
| †One case was excluded from the analysis because the laterality of mobile phone use was unknown. For the analysis, the matched pair was excluded from the analysis. | ||||
| ‡Ipsilateral use: a case was classified as exposed when the laterality of mobile phone use was the same as the laterality of tumour. A control was classified as exposed when the laterality of mobile phone use was the same as the laterality of the tumour of the matched case. If a subject used both ears for phone use, the subject was classified as exposed. The reference group was defined as the non-regular users or regular users whose phone use occurred on the side opposite the tumour. | ||||
| §Contralateral use: a case was classified as exposed when the laterality of mobile phone use was the opposite of the laterality of the tumour. A control was classified as exposed when the laterality of mobile phone use was the opposite of the laterality of the tumour of the matched case. If a subject used both ears for phone use, the subject was classified as exposed. The reference group was defined as the non-regular users or regular users whose phone use occurred on the same side as the tumour. | ||||
| Mobile phone use | ||||
| Non-user | 138 (41.82) | 46 (47.42) | 1.0 | |
| Regular user | 192 (58.18) | 51 (52.58) | 0.73 (0.43–1.23) | |
| Cumulative length of use (years) | ||||
| Non-user | 138 (41.82) | 46 (47.42) | 1.0 | |
| <4 | 111 (33.64) | 26 (26.80) | 0.70 (0.39–1.27) | |
| 4–7 | 69 (20.91) | 21 (21.65) | 0.76 (0.38–1.53) | |
| 8+ | 12 (3.64) | 4 (4.12) | p = 0.702 | 0.79 (0.24–2.65) |
| Cumulative call time (hours) | ||||
| Non-user | 138 (41.82) | 46 (47.42) | 1.0 | |
| <300 | 147 (44.55) | 35 (36.08) | 0.67 (0.38–1.17) | |
| 300–900 | 17 (5.15) | 9 (9.28) | 1.37 (0.54–3.50) | |
| 900+ | 28 (8.48) | 7 (7.22) | p = 0.694 | 0.67 (0.25–1.83) |
| Type of mobile phone used | ||||
| Non-user | 138 (41.82) | 46 (47.42) | 1.0 | |
| Analogue+digital | 10 (3.03) | 5 (5.15) | 1.19 (0.37–3.79) | |
| Digital only | 182 (54.15) | 46 (47.42) | 0.68 (0.40–1.18) | |
| Laterality of tumour location v mobile phone use† | ||||
| Ipsilateral use‡ | ||||
| Reference | 255 (77.74) | 76 (79.17) | 1.0 | |
| Ipsi-use | 73 (22.26) | 20 (20.83) | 0.90 (0.50–1.62) | |
| Contralateral use§ | ||||
| Reference | 199 (60.67) | 59 (61.46) | 1.0 | |
| Contra-use | 129 (39.33) | 37 (38.54) | 0.93 (0.55–1.59) | |