Topic

Epidemiological study on childhood cancer and proximity to radio and television transmitters

Start

01.03.2005

End

29.02.2008

Project Management

University of Mainz, Institute for Medical Biometry, Epidemiology und Informatics

Objective

There are only few epidemiological studies available investigating the association between the exposure to high frequency electromagnetic fields and cancer. Among those there has been a small number of studies showing an increased rate of childhood leukaemia near powerful radio or television transmitters. These studies were designed as ecological studies using geographically aggregated data instead of individual data, thus including a lot of major limitations. Systematic investigations are missing to date. The objective of the project was to investigate in a nation-wide epidemiological study in Germany the risk of childhood leukaemia in the vicinity of powerful radio and television transmitters. In a feasibility study it was investigated, whether an improved study design could be developed. This included the development of methods for the assessment of exposures, the definition of a suitable study region, the determination and consideration of important confounders (other relevant correlated risk factors) and the assessment of the statistical power of such a study. In case of positive results from the pilot study, a subsequent main study would be performed.

Results of the feasibility study

The feasibility study resulted in an improved study design that allows the assessment of risk of childhood leukaemia in the vicinity of powerful radio and television transmitters in Germany. The study design was defined as case-control study without conducting interviews. The study included 16 amplitude modulated (AM) and 8 frequency-modulated (FM) transmitters. The study area was defined by all communities lying within the doubled 1 V/m - radius around the corresponding AM-transmitters or within the theoretical 90 dB (µV/m) - radius around the corresponding UKW/TV-transmitters. The leukaemia cases were registered at the German childhood cancer registry. Inclusion criteria were: 1) Primary leukemia (ICD C91-C95), 2) date of first diagnose between 1984 und 2003, 3) age at diagnose between 0 to 14 years and 4) residence at the time of diagnose in the study area. Three age-, gender- and transmitter area-matched controls per case were drawn randomly from population registries. The individual exposure to RF-EMF one year before diagnosis was calculated with a field strength prediction program. The report on the feasibility study and on the details to the study design (both in German) can be downloaded as PDF-file:

Feasibility Study (1.447 KB)

Operation Manual (290 KB)

Results of the case-control study

The study included 1.959 cases and 5.848 controls. Cases were aged 0-14 years, diagnosed with primary leukaemia between 1984 and 2003, registered at the German childhood cancer registry, and living in the surrounding of the 16 AM and 8 UKW-/TV transmitters in Western Germany. Three age-, gender - and transmitter area-matched controls per case were drawn from population registries. The individual exposure to RF-EMF one year before diagnosis was calculated with a field strength prediction program. The exposure time period was defined from 1983-2002. In a validation study the exposure misclassification was analysed by using field measures as gold-standard that were collected independently from the model used for field strength calculation. There was a good agreement between measured and calculated field strength. The proxy distance (residence and main transmitter) was worse than the calculated field strength.

Main results:

• There is no statistical significant association between exposure to RF-EMF field from radio and television transmitters and childhood leukaemia.
• There is no association between childhood leukaemia and exposure to RF-EMF fields when the analysis was conducted separately for AM and FM transmitters.

Start

• No association between childhood leukaemia and exposure to RF-EMF fields was observed after dividing the observation period into 1983-1991 and 1992 to 2002, representing times periods before and after the widespread use of mobile telecommunication.
• No association between the proxy distance of residence to the main transmitter and childhood leukaemia was observed.
• The calculated field strength provides a better estimate of exposure to RF-EMF than the distance from the residence to the main transmitter.

Detailed results can be found in the final report (in German), which is available as PDF-file:

Final Report (630 KB)

Publications

• Brüggemeyer H, Philipp J, Merzenich H, Schmiedel S, Blettner M, Schüz J. Kindliche Leukämien und EMF-Expositionen in der Umgebung hochfrequenter Sendestationen (KiSS) - Fragestellung und Studienbeschreibung. Advances in Radio Science 2007;5:183-188.
• Merzenich H, Schmiedel S, Bennack S, Brüggemeyer H, Philipp J, Spix C, Blettner M, Schüz J. Leukämie bei Kindern in der Umgebung von Sendestationen des Rundfunks - Anforderungen an das Studiendesign. Umweltmedizin in Forschung und Praxis 2007;12 (4):213-223.
• Philipp J, Merzenich H, Brüggemeyer H, Schmiedel S, Blettner M, Schüz J. Retrospektive Bestimmung der elektromagnetischen Exposition durch analoge Rundfunksender im Rahmen von KiSS. Advances in Radio Science 2007;5:1-10.
• Schüz J, Philipp J, Merzenich H, Schmiedel S, Brüggemeyer H. Re: Radio-frequency radiation exposure from AM radio transmitters and childhood leukemia and brain cancer. American J Epidemiol (2008);167(7):883-4.
• Merzenich H, Schmiedel S, Bennack S, Brüggemeyer H, Philipp J, Blettner M, Schüz J. Childhood Leukemia in Relation to Radio Frequency Electromagnetic Fields in the Vicinity of Television and Radio Broadcast Transmitters. American J Epidemiol (2008); 15;168(10):1169-78.
• Schmiedel S, Brüggemeyer H, Philipp J, Wendler J, Merzenich H, Schüz J. An evaluation of exposure metrics in an epidemiologic study on radio and television broadcast transmitters and the risk of childhood leukemia. Bioelectromagnetics 2009; DOI: 10.1002/bem.20460.

Conclusion

The study provides no evidence for an increased risk of childhood leukaemia due to RF-EMF fields of radio- and television transmitters. The improved study design, including the individual exposure assessment for almost 8000 children, the long observation period of 20 years, as well as the focus on 24 of the most powerful transmitters in Germany, clearly weakens former single findings of an increased risk of childhood leukaemia based on studies using an ecologic study design.