Study type: Epidemiological study (observational study)

Pooled analysis of case-control studies on malignant brain tumours and the use of mobile and cordless phones including living and deceased subjects. epidem.

Published in: Int J Oncol 2011; 38 (5): 1465-1474

Aim of study (acc. to author)

A pooled analysis of three case-control studies on the use of mobile phones and cordless phones and the risk of malignant brain tumors was conducted in Sweden.

Further details

Cases who died before they could be interviewed about their mobile phone use were excluded in the publication of Hardell et al (2006) which might have led to bias. Therefore following studies were included in the present pooled-analysis including all alive and deceased cases between 1997-2003: The first case-control study regarding the period 1997-2000 was published in the publications 9520 and 9895, the second study regarding the period 2000-2003 in publications 12068 and 12259, and the third study regarding deceased cases and controls in the period 1997-2003 in publication 18358.

Endpoint/type of risk estimation

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

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 unexposed: no mobile or cordless phone use or less than 1 year
Group 2 mobile + cordless phone use ≤ 195 h, > 1 to 5 years
Group 3 mobile + cordless phone use ≤ 195 h, > 5 to 10 years
Group 4 mobile + cordless phone use ≤ 195 h, > 10 years
Group 5 mobile + cordless phone use ≤ 195 h, total, > 1 year
Group 6 mobile + cordless phone use > 195 h, > 1 to 5 years
Group 7 mobile + cordless phone use > 195 h, > 5 to 10 years
Group 8 mobile + cordless phone use > 195 h, > 10 years
Group 9 mobile + cordless phone use > 195 h, total, > 1 year
Group 10 mobile phone use ≤ 74 h, > 1 to 5 years
Group 11 mobile phone use ≤ 74 h, > 5 to 10 years
Group 12 mobile phone use ≤ 74 h, > 10 years
Group 13 mobile phone use ≤ 74 h, total, > 1 year
Group 14 mobile phone use > 74 h, > 1 to 5 years
Group 15 mobile phone use > 74 h, > 5 to 10 years
Group 16 mobile phone use > 74 h, > 10 years
Group 17 mobile phone use > 74 h, total, > 1 year
Group 18 cordless phone use ≤ 243 h, > 1 to 5 years
Group 19 cordless phone use ≤ 243 h, > 5 to 10 years
Group 20 cordless phone use ≤ 243 h, > 10 years
Group 21 cordless phone use ≤ 243 h, total, > 1 year
Group 22 cordless phone use > 243 h, > 1 to 5 years
Group 23 cordless phone use > 243 h, > 5 to 10 years
Group 24 cordless phone use > 243 h, > 10 years
Group 25 cordless phone use > 243 h, total, > 1 year
Group 26 mobile + cordless phone, cumulative lifetime use: 1 - 1,000 h
Group 27 mobile + cordless phone, cumulative lifetime use: 1,001 - 2,000 h
Group 28 mobile + cordless phone, cumulative lifetime use: > 2,000 h
Group 29 mobile phone, cumulative lifetime use: 1 - 1,000 h
Group 30 mobile phone, cumulative lifetime use: 1,001 - 2,000 h
Group 31 mobile phone, cumulative lifetime use: > 2,000 h
Group 32 cordless phone, cumulative lifetime use: 1 - 1,000 h
Group 33 cordless phone, cumulative lifetime use: 1,001 - 2,000 h
Group 34 cordless phone, cumulative lifetime use: > 2,000 h
Group 35 mobile + cordless phone use, > 1 to 5 years
Group 36 mobile + cordless phone use, > 5 to 10 years
Group 37 mobile + cordless phone use, > 10 years
Group 38 mobile + cordless phone use, total, > 1 year
Group 39 mobile phone use, > 1 to 5 years
Group 40 mobile phone use, > 5 to 10 years
Group 41 mobile phone use, > 10 years
Group 42 mobile phone use, total, > 1 year
Group 43 cordless phone use, > 1 to 5 years
Group 44 cordless phone use, > 5 to 10 years
Group 45 cordless phone use, > 10 years
Group 46 cordless phone use, total, > 1 year
Group 47 mobile + cordless phone use, first use < 20 years old
Group 48 mobile + cordless phone use, first use 20 - 49 years old
Group 49 mobile + cordless phone use, first use ≥ 50 years old
Group 50 mobile phone use, first use < 20 years old
Group 51 mobile phone use, first use 20 - 49 years old
Group 52 mobile phone use, first use ≥ 50 years old
Group 53 cordless phone use, first use < 20 years old
Group 54 cordless phone use, first use 20 - 49 years old
Group 55 cordless phone use, first use ≥ 50 years old

Population

Case group

Control group

Study size

Cases Controls
Eligible 1,472 2,900
Participants 1,251 2,438
Participation rate 85 % 84 %
Statistical analysis method: (adjustment: )

Conclusion (acc. to author)

The main result of this pooled analysis was an increased risk for malignant brain tumor and the use of both mobile phones and cordless phones. The highest risk was observed for the most common type of glioma, astrocytoma, in the > 10 years latency group for mobile phones use (OR 2.7, CI 1.9-3.7) and for cordless phone use (OR 1.8, CI 1.2-2.9). The risk for astrocytoma was highest in the group with first use of a mobile phone or cordless phone before the age of 20 (mobile phone use: OR 4.9, CI 2.2-11; cordless phone use: OR 3.9, CI 1.7-8.7).
The authors concluded that the risk for malignant brain tumors increased with latency time and cumulative use of mobile phones and cordless phones in hours and was highest in subjects with first use before the age of 20.

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