Epidemiological study (observational study)

Further aspects on cellular and cordless telephones and brain tumours.

Published in: Int J Oncol 2003; 22 (2): 399-407

Aim of study (acc. to author)

In this study, further analyses were performed on the database of a Swedish case-control study (see publication 9105) on the use of cellular telephones and cordless telephones and the risk of brain tumors.

Further details

Furthermore, there are additional analyses of the database of the same case-control study (publication 9105) published in publications 9361, 11953 and 12393.
Subjects without exposure to cellular phone or cordless phone were classified as unexposed.

Endpoint/type of risk estimation

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

Exposure

Assessment

  • questionnaire: type of phone, years of use, brand name, first part of number (to differentiate between analog and digital), mean number and minutes of daily calls, use in car with fixed external antenna or hands-free device, ear most frequently used during calls
  • interview: supplementing data
  • calculation: cumulative use in hours

Exposure groups

Reference group 1 unexposed
Group 2 analog, 450 MHz, > 1 year latency
Group 3 analog, 450 MHz, > 5 years latency
Group 4 analog, 450 MHz, > 10 years latency
Group 5 analog, 900 MHz, > 1 year latency
Group 6 analog, 900 MHz, > 5 years latency
Group 7 analog, 900 MHz, > 10 years latency
Group 8 analog, all, > 1 year latency
Group 9 analog, all, > 5 years latency
Group 10 analog, all, >10 years latency
Group 11 analog, ≤ 85 h, > 1 year latency
Group 12 analog, ≤ 85 h, > 5 years latency
Group 13 analog, ≤ 85 h, >10 years latency
Group 14 analog, > 85 h, > 1 year latency
Group 15 analog, > 85 h, > 5 years latency
Group 16 analog, > 85 h, > 10 years latency
Group 17 digital, all, > 1 year latency
Group 18 digital, all, > 5 years latency
Group 19 digital, all, >10 years latency
Group 20 digital, ≤ 55 h, > 1 year latency
Group 21 digital, ≤ 55 h, > 5 years latency
Group 22 digital, ≤ 55 h, >10 years latency
Group 23 digital, > 55 h, > 1 year latency
Group 24 digital, > 55 h, > 5 years latency
Group 25 digital, > 55 h, >10 years latency
Group 26 cordless, all, > 1 year latency
Group 27 cordless, all, > 5 years latency
Group 28 cordless, all, > 10 years latency
Group 29 cordless, ≤ 183 h, > 1 year latency
Group 30 cordless, ≤ 183 h, > 5 years latency
Group 31 cordless, ≤ 183 h, > 10 years latency
Group 32 cordless, > 183 h, > 1 year latency
Group 33 cordless, > 183 h, > 5 years latency
Group 34 cordless, > 183 h, > 10 years latency
Group 35 analog, brain hemisphere ipsilateral
Group 36 digital, brain hemisphere ipsilateral
Group 37 cordless, brain hemisphere ipsilateral
Group 38 analog, brain hemisphere contralateral
Group 39 digital, brain hemisphere contralateral
Group 40 cordless, brain hemisphere contralateral
Group 41 analog, temporal area, ipsilateral
Group 42 digital, temporal area, ipsilateral
Group 43 cordless, temporal area, ipsilateral
Group 44 analog, temporal area, contralateral
Group 45 digital, temporal area, contralateral
Group 46 cordless, temporal area, contralateral

Population

  • Group:
    • men
    • women
  • Age: 20–80 yr
  • Observation period: January 1997 - June 2000
  • Study location: Sweden (Uppsala/Örebro, Stockholm, Linköping and Göteborg regions)

Case group

Control group

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

Study size

Cases Controls
Eligible 1,617 -
Contacted 1,617 1,617
Participants 1,429 1,470
Participation rate 88 91
Statistical analysis method:
  • unconditional logistic regression
( adjustment:
  • age
  • sex
  • socioeconomic status
)

Conclusion (acc. to author)

The results showed an increased risk of brain tumor for use of analog cellular phones, but not for digital cellular phones or cordless phones. The risk of brain tumor was increased among ipsilateral users of analog and digital cellular phones, also for users of cordless phones, but not significantly.

Study funded by

  • Cancer och Allergifonden (Cancer and Allergy Foundation), Sweden
  • Örebro Cancer Fund, Sweden
  • Swedish Work Environment Fund
  • Telia, Sweden

Related articles