Epidemiological study (observational study)

Case-control study of the association between the use of cellular and cordless telephones and malignant brain tumors diagnosed during 2000-2003 epidem.

By: Hardell L, Carlberg M, Hansson Mild K

Published in: Environ Res 2006; 100 (2): 232-241

Aim of study (acc. to author)

A case-control study on the use of cellular and cordless telephones and the risk for brain tumors was conducted in Sweden.

Further details

This study reports results for malignant brain tumors whereas the results for benign brain tumors, mainly meningioma and acoustic neuroma, are presented in publication 12068.
Subjects who started their use of a mobile or cordless phone within one year prior diagnosis were classified as unexposed.

Endpoint/type of risk estimation

brain tumor: malignant brain tumor

Type of risk estimation:

incidence

(odds ratio (OR))

Exposure

- mobile communications
- analog mobile phone
- digital mobile phone
- cordless phone
- personal

Assessment

questionnaire: mean number of daily calls and minutes, use in a car with fixed external antenna, use of hands-free device, ear most frequently used during calls, first part of telephone number (to differentiate between analog and digital cellular phones), network operator
interview: supplementing data
calculation: cumulative use in hours

Exposure groups

Group	Description
Reference group 1	unexposed
Group 2	analog, 1-5-year-latency
Group 3	analog, > 5-10-year latency
Group 4	analog, > 10-year latency
Group 5	analog, total, > 1-year latency
Group 6	analog, ≤ 80 h, 1-5-year-latency
Group 7	analog, ≤ 80 h, 5-10-year-latency
Group 8	analog, ≤ 80 h, > 10-year latency
Group 9	analog, ≤ 80 h, total, > 1-year latency
Group 10	analog, > 80 h, 1-5-year-latency
Group 11	analog, > 80 h, 5-10-year-latency
Group 12	analog, > 80 h, > 10-year latency
Group 13	analog, > 80 h, total, > 1-year latency
Group 14	digital, 1-5-year-latency
Group 15	digital, > 5-10-year latency
Group 16	digital, > 10-year latency
Group 17	digital, total, > 1-year latency
Group 18	digital, ≤ 64 h, 1-5-year-latency
Group 19	digital, ≤ 64 h, > 5-10-year latency
Group 20	digital, ≤ 64 h, > 10-year latency
Group 21	digital, ≤ 64 h, total, > 1-year latency
Group 22	digital, > 64 h, 1-5-year-latency
Group 23	digital, > 64 h, > 5-10-year latency
Group 24	digital, > 64 h, > 10-year latency
Group 25	digital, > 64 h, total, > 1-year latency
Group 26	cordless, 1-5-year-latency
Group 27	cordless, > 5-10-year latency
Group 28	cordless, > 10-year latency
Group 29	cordless, total, > 1-year latency
Group 30	cordless, ≤ 243 h, 1-5-year-latency
Group 31	cordless, ≤ 243 h, > 5-10-year latency
Group 32	cordless, ≤ 243 h, > 10-year latency
Group 33	cordless, ≤ 243 h, total, > 1-year latency
Group 34	cordless, > 243 h, 1-5-year-latency
Group 35	cordless, > 243 h, > 5-10-year latency
Group 36	cordless, > 243 h, > 10-year latency
Group 37	cordless, > 243 h, total, > 1-year latency

Population

Group:
- men
- women
Age: 20–80 years
Observation period: July 2000 - December 2003
Study location: Sweden (Uppsala/Örebro and Linköping regions)

Case group

Characteristics: malignant brain tumor, histopathologically verified
Data source: Cancer Registry
Exclusion criteria: deceased, medical conditions

Control group

Selection:
- population-based
Matching:
- sex
- age
- area
- case:control = 1:1

Study size

	Cases	Controls
Eligible	359	820
Participants	317	692
Participation rate	88 %	84 %

Statistical analysis method:

unconditional logistic regression

(adjustment:

age
sex
socioeconomic status
year of diagnosis

)

Results (acc. to author)

The results showed an increased risk for malignant brain tumors in association with the use of analog and digital cellular phones and cordless phones. The risk increased with the latency period and the number of hours use for phone calls.

Study funded by

Cancer och Allergifonden (Cancer and Allergy Foundation), Sweden
Cancerhjälpen (Cancerhelp), Sweden
Nyckelfonden, Sweden
Örebro Cancer Fund, Sweden

Comments on this article

Morgan LL (2006): Re: "Cellular phones, cordless phones, and the risks of glioma and meningioma (Interphone Study Group, Germany)"

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