Average output power (mW) and percentage maximum power by call characteristics and phone use circumstances
| 900 MHz | 1800 MHz | PMax (%) | ||||||
| Mean (SD) power* | Regression coefficient (95% CI)† | Mean (SD) power | Regression coefficient (95% CI) | Mean (SD), % | Regression coefficient (95% CI) | |||
| Duration of call | No of calls | |||||||
| >60 s | 27789 | 128.2 (87.8) | – | 62.7 (43.7) | – | 36.1 (37.9) | – | |
| 30–60 s | 13265 | 133.1 (91.2) | 0.9 (−1.0 to 2.8) | 63.8 (45.9) | 0.2 (−1.1 to 1.4) | 38.2 (40.0) | 0.8 (0.1 to 1.6) | |
| 10–30 s | 13805 | 134.6 (94.4) | 5.5 (3.6 to 7.4) | 63.3 (46.0) | 1.1 (−0.2 to 2.3) | 39.2 (41.0) | 3.0 (2.3 to 3.7) | |
| 5–10 s | 3961 | 141.8 (98.2) | 13.3 (10.1 to 16.6) | 70.8 (48.3) | 9.2 (7.1 to 11.3) | 44.5 (43.3) | 8.5 (7.3 to 9.7) | |
| <5 s | 4331 | 159.1 (101.5) | 27.8 (24.7 to 30.9) | 76.4 (52.4) | 14.3 (12.1 to 16.4) | 53.8 (47.0) | 16.5 (15.3 to 17.6) | |
| Time of day | ||||||||
| Night (23 h–8 h) | 3649 | 140.7 (91.4) | – | 63.3 (45.8) | – | 41.5 (40.9) | – | |
| Day (8 h–19 h) | 48192 | 132.2 (91.3) | −5.1 (−8.3 to −1.8) | 63.9 (45.3) | 1.1 (−1.1 to 3.2) | 38.2 (40.0) | −2.4 (−3.6 to −1.1) | |
| Evening (19 h–23 h) | 11250 | 135.2 (93.4) | 0.1 (−3.5 to 3.7) | 65.6 (46.3) | 2.7 (0.3 to 5.1) | 41.4 (41.3) | 0.3 (−1.1 to 1.7) | |
| Use of phone in urban/rural location | ||||||||
| No of subjects | ||||||||
| Mainly urban | 393 | 129.0 (92.1) | – | 61.8 (45.6) | – | 37.2 (40.0) | – | |
| Mainly rural | 34 | 138.4 (93.6) | 17.3 (4.0 to 30.6) | 63.4 (43.2) | 7.9 (−1.1 to 17.0) | 43.5 (41.6) | 8.2 (2.3 to 14.0) | |
| Both urban and rural | 64 | 155.1 (85.2) | 3.9 (−6.8 to 14.5) | 80.4 (42.2) | 7.9 (1.9 to 13.9) | 48.2 (40.0) | 2.7 (−1.6 to 7.0) | |
| Use of phone while moving in vehicle‡ | ||||||||
| Never | 182 | 139.4 (91.7) | – | 70.5 (45.9) | – | 41.8 (41.3) | – | |
| Less than half | 172 | 136.1 (90.4) | −5.0 (−13.1 to 3.2) | 63.6 (44.9) | −2.6 (−7.3 to 2.0) | 39.3 (39.9) | −3.5 (−6.9 to −0.1) | |
| About half | 56 | 124.5 (92.1) | 0.8 (−11.4 to 13.1) | 64.2 (44.6) | −3.3 (−9.7 to 3.1) | 36.8 (39.6) | −2.0 (−6.8 to 2.8) | |
| More than half | 28 | 119.4 (89.7) | −6.0 (−21.7 to 9.8) | 55.4 (42.3) | −4.8 (−13.2 to 3.6) | 35.8 (38.5) | −3.4 (−9.7 to 2.9) | |
| Nearly always | 7 | 161.6 (82.6) | 15.5 (−18.8 to 49.7) | 61.1 (43.7) | −0.5 (−15.8 to 14.8) | 44.4 (39.6) | 2.5 (−9.5 to 14.4) | |
| Use of phone inside buildings§ | ||||||||
| Never | 19 | 133.6 (80.2) | – | 59.2 (41.6) | – | 33.2 (36.0) | – | |
| Less than half | 58 | 123.7 (90.7) | −7.2 (−27.8 to 13.4) | 60.5 (44.4) | 2.5 (−8.2 to 13.2) | 36.0 (39.6) | 1.0 (−7.4 to 9.3) | |
| About half | 81 | 146.1 (88.0) | −2.6 (−22.6 to 17.3) | 69.8 (45.3) | 2.2 (−8.1 to 12.5) | 41.6 (40.4) | 1.2 (−6.8 to 9.3) | |
| More than half | 88 | 125.5 (92.0) | −11.3 (−31.5 to 8.8) | 59.2 (45.8) | 1.5 (−9.0 to 12.1) | 36.9 (39.9) | −1.7 (−9.9 to 6.6) | |
| Nearly always | 60 | 120.8 (94.0) | −9.8 (−30.5 to 11.0) | 65.3 (46.3) | 2.3 (−8.7 to 13.2) | 36.8 (40.3) | 0.01 (−8.5 to 8.5) | |
*Unadjusted power level. †Regression coefficient for difference in output power (in mW) between specified category and the comparison category (–); from linear regression model adjusted for operator, call duration and software-modified phone model. ‡Not included in the questionnaire in Sweden. §Only included in questionnaires in later part of the study: not in Denmark, France, Germany, Sweden or UK North 1.
PMax, maximum power.