Study type: Epidemiological study (observational study)

Acoustic neuroma risk in relation to mobile telephone use: Results of the INTERPHONE international case-control study. epidem.

Published in: Cancer Epidemiol 2011; 35 (5): 453-464

Aim of study (acc. to author)

An international case-control study (INTERPHONE) was conducted in 13 countries to determine whether mobile phone use increases the risk of brain tumors.

Further details

The INTERPHONE study was initiated as an international set of case-control studies conducted in 13 countries (Australia, Canada, Denmark, Finland, France, Germany, Israel, Italy, Japan, New Zealand, Norway, Sweden and the UK) focussing on four types of tumors (glioma, meningioma, acoustic neurinoma, and parotid gland tumor) in tissues that most absorb radiofrequency energy emitted by mobile phones. In the present publication the results of the analysis of the acoustic neuroma risk are presented, an earlier publication 18215 covers the results for the risk of glioma and meningioma.
Sensitivity analyses were performed to detect potential sources for bias.
Regular use of a mobile phone was defined as at least once a week for at least six months.

Endpoint/type of risk estimation

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

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 regular use: no
Group 2 regular use: yes
Reference group 3 never regular use
Group 4 time since start of use: 1-1.9 years
Group 5 time since start of use: 2-4 years
Group 6 time since start of use: 5-9 years
Group 7 time since start of use: ≥ 10 years
Reference group 8 never regular use
Group 9 cumulative call time: < 5 h
Group 10 cumulative call time: 5-12.9 h
Group 11 cumulative call time: 13-30.9 h
Group 12 cumulative call time: 31-60.9 h
Group 13 cumulative call time: 61-114.9 h
Group 14 cumulative call time: 115-199.9 h
Group 15 cumulative call time: 200-359.9 h
Group 16 cumulative call time: 360-734.9 h
Group 17 cumulative call time: 735-1639.9 h
Group 18 cumulative call time: ≥ 1640 h
Reference group 19 never regular use
Group 20 cumulative number of calls: < 150
Group 21 cumulative number of calls: 150-349
Group 22 cumulative number of calls: 350-749
Group 23 cumulative number of calls: 750-1.399
Group 24 cumulative number of calls: 1,400-2,549
Group 25 cumulative number of calls: 2,550-4,149
Group 26 cumulative number of calls: 4,150-6,799
Group 27 umulative number of calls: 6,800-12,799
Group 28 cumulative number of calls: 12,800-26,999
Group 29 cumulative number of calls: ≥ 27,000
Reference group 30 no ipsilateral mobile phone use
Group 31 ipsilateral mobile phone use
Reference group 32 never regular use
Group 33 ipsilateral use, time since start of use: 1-1.9 years
Group 34 ipsilateral use, time since start of use: 2-4 years
Group 35 ipsilateral use, time since start of use: 5-9 years
Group 36 ipsilateral use, time since start of use: ≥ 10 years
Reference group 37 no regular use
Group 38 ipsilateral use, cumulative call time: < 5 h
Group 39 ipsilateral use, cumulative call time: 5-114.9 h
Group 40 ipsilateral use, cumulative call time: 115-359.9 h
Group 41 ipsilateral use, cumulative call time: 360-1639.9 h
Group 42 ipsilateral use, cumulative call time: ≥ 1640 h
Reference group 43 no regular use
Group 44 ipsilateral use, cumulative number of calls: 150
Group 45 ipsilateral use, cumulative number of calls: 150-2,549
Group 46 ipsilateral use, cumulative number of calls: 2,550-6,799
Group 47 ipsilateral use, cumulative number of calls: 6,800-26,999
Group 48 ipsilateral use, cumulative number of calls: ≥ 27,000
Reference group 49 no regular use
Group 50 contralateral use, time since start of use: 1-1.9 years
Group 51 contralateral use, time since start of use: 2-4 years
Group 52 contralateral use, time since start of use: 5-9 years
Group 53 contralateral use, time since start of use: ≥ 10 years
Reference group 54 no regular use
Group 55 contralateral use, cumulative call time: < 5 h
Group 56 contralateral use, cumulative call time: 5-114.9 h
Group 57 contralateral use, cumulative call time: 115-359.9 h
Group 58 contralateral use, cumulative call time: 360-1639.9 h
Group 59 contralateral use, cumulative call time: ≥ 1640 h
Reference group 60 no regular use
Group 61 contralateral use, cumulative number of calls: 150
Group 62 contralateral use, cumulative number of calls: 150-2,549
Group 63 contralateral use, cumulative number of calls: 2,550-6,799
Group 64 contralateral use, cumulative number of calls: 6,800-26,999
Group 65 contralateral use, cumulative number of calls: ≥ 27,000

Population

Case group

Control group

Study size

Cases Controls
Eligible 1,361 14,354
Participants 1,121 7,658
Evaluable 1,105 2,145
Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

Overall, no increased risk for acoustic neuroma was observed with ever having been a regular mobile phone user (group 2) and for persons with 10 years and longer mobile phone use (group 7). No trend of increasing ORs with increasing cumulative call time or cumulative number of calls was observed, with the lowest OR (0.48; CI 0.30-0.78) observed in the second highest group of cumulative call time (735 -1639.9 h). In the highest group (≥ 1640 h) of cumulative call time, the OR was 1.32 (CI 0.88-1.97); but there were implausible values reported in this group (e.g., mobile phone use more than 5 h/day). Similar results were observed when restricting the analysis at 5 years before the reference date (to exclude possible effects of prodomal symptoms on mobile phone use).
In general, odds ratios were not greater in subjects who reported usual phone use on the same side of the head as their tumor (ipsilateral) than in persons with contralateral use, but it was greater in those with 1640 and more cumulative hours of use.
The authors concluded that there was no increase in risk of acoustic neuroma with ever regular use of a mobile phone or for users who began regular use 10 years or more before the reference date. Elevated odds ratios observed at the highest level of cumulative call time could be due to chance, reporting bias or a causal effect. As acoustic neuroma is usually a slowly growing tumour, the interval between introduction of mobile phones and occurrence of the tumor might have been too short to observe an effect, if there is one.

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