A population-based case-control study was conducted in Sweden to investigate the association between long-term mobile phone use and the risk of acoustic neuroma. Additionally detailed information about the history of laterality of phone use were collected to allow evaluation of potential reverse causality in laterality analyses.
Regular mobile phone use was defined as having made or received a call on average at least once per week during at least 6 months.
|Reference group 1||mobile phone use: never or rarely|
|Group 2||mobile phone use: regular|
|Reference group 3||duration of regular mobile phone use: < 5 years|
|Group 4||duration of regular mobile phone use: 5 - 9 years|
|Group 5||duration of regular mobile phone use: ≥ 10 years|
|Reference group 6||time since first regular use: < 5 years|
|Group 7||time since first regular use: 5 - 9 years|
|Group 8||time since first regular use: ≥ 10 years|
|Group 9||time since first regular use: 10 -12 years|
|Group 10||time since first regular use: ≥ 13 years|
|Reference group 11||cumulative hours of use: < 38|
|Group 12||cumulative hours of use: 38 - 189|
|Group 13||cumulative hours of use: 190 - 679|
|Group 14||cumulative hours of use: ≥ 680|
|Reference group 15||cumulative number of calls: < 1100|
|Group 16||cumulative number of calls: 1100 - 4400|
|Group 17||cumulative number of calls: 4400 - 13850|
|Group 18||cumulative number of calls: ≥ 13850|
|Participation rate||83 %||65 %|
52% of the cases with regular use and 8% of the controls reported that they had changed their preferred side of mobile phone use. For cases, the most common reason for changing side of phone use was hearing loss (91%) and for controls 'practical reasons' (40%).
Regular mobile phone use was associated with an odds ratio (OR) of 1.18 (CI 0.88-1.59). The association was weaker for the longest induction time (≥ 10 years: OR 1.11; CI 0.76 to 1.61) and for regular use on the tumor side (ipsilateral: OR 0.98; CI 0.68-1.43). The OR for the highest quartile of cumulative calling time (≥ 680 hours) was 1.46 (CI 0.98-2.17). Restricting analyses to histologically confirmed cases reduced all odds ratios (≥ 680 hours: OR 1.14; CI 0.63-2.07). A similar pattern was seen for cordless phones, although with slightly higher ORs. Analyses of the complete history of laterality of mobile phone revealed considerable bias in laterality analyses.
The authors conclude that the findings do not support the hypothesis that long-term mobile phone use increases the risk of acoustic neuroma. The study suggests that phone use might increase the likelihood that an acoustic neuroma case is detected and that there could be bias in the laterality analyses performed in previous studies.