A multicentric case-control study (CEFALO) was conducted in Denmark, Sweden, Norway, and Switzerland to investigate the relationship between mobile phone use and risk of developing brain tumors in children and adolescents.
Regular use was defined as use of a mobile phone at least once per week for a period of 6 months or more.
|Reference group 1||non-regular mobile phone user|
|Group 2||regular mobile phone user|
|Reference group 3||time since first use: never regular user|
|Group 4||time since first use: ≤ 3.3 years|
|Group 5||time since first use: 3.3 - 5.0 years|
|Group 6||time since first use: > 5.0 years|
|Reference group 7||cumulative duration of subscriptions: never regular user|
|Group 8||cumulative duration of subscriptions: ≤ 2.7 years|
|Group 9||cumulative duration of subscriptions: 2.8 - 4.0 years|
|Group 10||cumulative duration of subscriptions: > 4.0 years|
|Reference group 11||cumulative duration of calls: never regular user|
|Group 12||cumulative duration of calls: ≤ 35 h|
|Group 13||cumulative duration of calls: 36 - 144 h|
|Group 14||cumulative duration of calls: > 144 h|
|Reference group 15||cumulative number of calls: never regular user|
|Group 16||cumulative number of calls: ≤ 936|
|Group 17||cumulative number of calls: 937 - 2638|
|Group 18||cumulative number of calls: > 2638|
|Reference group 19||ever use of baby monitors near the head: no|
|Group 20||ever use of baby monitors near the head: yes|
|Reference group 21||ever use of cordless phones: no|
|Group 22||ever use of cordless phones: yes|
|Reference group 23||cumulative duration of calls with cordless phones: never user|
|Group 24||cumulative duration of calls with cordless phones: ≤ 23 h|
|Group 25||cumulative duration of calls with cordless phones: 24 - 70 h|
|Group 26||cumulative duration of calls with cordless phones: > 70 h|
|Group 27||cumulative duration of calls with cordless phones: missing data|
|Reference group 28||cumulative number of calls with cordless phones: never user|
|Group 29||cumulative number of calls with cordless phones: ≤ 235|
|Group 30||cumulative number of calls with cordless phones: 236 - 704|
|Group 31||cumulative number of calls with cordless phones: > 704|
|Group 32||cumulative number of calls with cordless phones: missing data|
|Participation rate||83 %||71 %|
194 (55%) case patients and 329 (51%) control subjects have used regularly mobile phones.
Regular users of mobile phones were not statistically significantly more likely to have been diagnosed with brain tumors compared with nonusers (OR 1.36; CI 0.92-2.02). Children who started to use mobile phones at least 5 years ago were not at increased risk compared with those who had never regularly used mobile phones (OR 1.26; CI 0.70-2.28). In a small subset of study participants for whom operator recorded data were available, brain tumor risk was related to the time elapsed since the mobile phone subscription was started but not to amount of use. No increased risk of brain tumors was observed for brain areas receiving the highest amount of exposure. The results showed no relationship between brain tumor risk and ever use of baby monitors near the head as well as children's use of cordless phones.
The authors conclude that the absence of an exposure-response relationship either in terms of the amount of mobile phone use or by localization of the brain tumor argues against a causal association.