Depending on the subjective symptoms, nonusers or the respective group with the lowest exposure level was selected as reference group.
(Remark EMF-Portal: Only the most important exposure groups are listed in the table below.)
|Reference group 1||mobile phone use: no|
|Group 2||mobile phone use: yes|
|Reference group 3||number of calls per day: < 1|
|Group 4||number of calls per day: 1 - 4|
|Group 5||number of calls per day: ≥ 5|
|Reference group 6||total duration of calls per day: < 5 min|
|Group 7||total duration of calls per day: 5 - 9 min|
|Group 8||total duration of calls per day: 10 - 30 min|
|Group 9||total duration of calls per day: > 30 min|
|Reference group 10||status and position of mobile phone at night: off|
|Group 11||status and position of mobile phone at night: on, ≥ 1 m away|
|Group 12||status and position of mobile phone at night: on, 25 - 99 cm away|
|Group 13||status and position of mobile phone at night: on, 0 - 24 cm away|
|Reference group 14||position during daytime: does not carry, leaves at home or in a furniture at school|
|Group 15||position of phone during daytime: on a belt or in the pocket or bag|
|Group 16||position of phone during daytime: in the pocket of overcoat or jacket|
|Reference group 17||status while studying: off|
|Group 18||status while studying: on, silent mode|
|Reference group 19||distance to base station: > 300 m|
|Group 20||distance to base station: ≤ 300 m|
|Reference group 21||exposure in school building: 1st quartile (≤ 0.602 V/m)|
|Group 22||exposure in school building: 2nd quartile (0.603 - 0.850 V/m)|
|Group 23||exposure in school building: 3rd quartile (0.851 - 1.51 V/m)|
|Group 24||exposure in school building: 4th quartile (≥ 1.52 V/m)|
Among the study participants, 2021 (94.0%) were using mobile phones. Among users, 49.4% were speaking less than 10 min per day and 52.2% were sending/receiving 75 or more messages per day. Fatigue was the most commonly reported symptom, followed by headache and irritability.
Headache, fatigue and sleep disturbances were observed more often among mobile phone users (group 2) compared to nonusers (group 1) (OR 1.90, CI 1.30–2.77; OR 1.78, CI 1.21–2.63 and OR 1.53, CI 1.05–2.21, resp.). Many statistically significant associations were found which cannot be expected by chance alone. Some of the observed associations showed dose-response relationships.
Limited associations were observed between vicinity to base stations and some general symptoms. No association was found with exposure at school.
The authors conclude that their findings suggest an association between mobile phone use and some subjective symptoms.