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Epidemiological study (observational study)

Long-term Mobile Phone Use and Acoustic Neuroma Risk.

Published in: Epidemiology 2014; 25 (2): 233-241

Aim of study (acc. to author)

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.

Further details

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.

Endpoint/type of risk estimation

Type of risk estimation:
  • incidence
(odds ratio (OR))

Exposure

Assessment

  • questionnaire: first year of regular use, stop of use including year, average number of calls, calling time, hands-free use, preferred side of the head to which the mobile phone was usually hold, change of preference, use of cordless phones
  • calculation: cumulative call time and cumulative number of calls

Exposure groups

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

Population

  • Group:
    • men
    • women
  • Age: 20–69 years
  • Observation period: September 2002 - August 2007
  • Study location: Sweden

Case group

  • Characteristics: acoustic neuroma
  • Data source: treating clinics, Swedish Regional Cancer Registers, local acoustic neuroma registries at the otorhinolaryngology clinics in the Uppsala and Linköpin
  • Exclusion criteria: neurofibromatosis, tuberous sclerosis

Control group

  • Selection:
    • population-based
  • Matching:
    • sex
    • area
    • 5-year age group
    • case:control = 1:2
  • Exclusion criteria: neurofibromatosis

Study size

Cases Controls
Eligible 542 1,095
Participants 451 710
Participation rate 83 % 65 %
Evaluable 422 643
Statistical analysis method:
  • conditional logistic regression

Conclusion (acc. to author)

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.

Study funded by

  • Swedish Council for Working Life and Social Research (FAS)

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