Topic

Feasibility study for a cohort study: the cohort study should investigate highly exposed (occupational) groups to estimate the risk associated with high frequency electromagnetic fields.

Start

01.08.2002

End

31.08.2003

Project Management

University of Bielefeld, University of Mainz, DKFZ Heidelberg, NFO Infratest Munich

Objective

So far no health risks to the general public from the electromagnetic fields of mobile telecommunications have been demonstrated. However, some evidence of health risks in highly exposed (occupational) groups does exist.
The objective of this project was to examine by means of a feasibility study whether a cohort study of highly exposed (occupational) groups can be carried out in Germany. A cohort study is an observational study in which a study population (a cohort) is selected and information is obtained for a specific exposure that is supposedly related to the development of specific diseases. The entire study population is then followed up in time, and the incidence of the disease in the exposed individuals is compared with the incidence in those not exposed. The objective of the feasibility study was to identify suitable exposed occupational groups and make recommendations for a study protocol, the course of study, relevant endpoints for investigation and determination of high frequency fields.

Results

Employees in 'radio', 'radar' and 'industrial production' occupations and various service professions are exposed to high frequency electromagnetic fields. Altogether, 30 occupational groups could be identified and were checked on fulfilling defined inclusion criteria.. The criteria met exposure conditions (regularity, duration and determination) and composition of the cohort group (group size, selection, demographic data). After having excluded all groups of people not fulfilling these criteria, three potential cohorts remained:

• Workers of high frequency plastic welding machines
• Engineers and / or technicians of middle and short-wave transmitters
• radio hams.

A possible study protocol was developed for these groups and the pros and cons of conducting such a cohort study were evaluated. The overall result of the evaluation of these three groups was that a study protocol for a cohort study could not be defined that would allow for an unbiased estimate of the health risk due to exposure to high frequency electromagnetic fields. The reasons for this were, among others, the low cohort size, incommensurable control groups of non-exposed persons, a large number of non-controllable other risk factors (mixed exposure, added chemical burden, etc.), difficulties with the retrospective exposure assessment and the lack of relevance for exposure conditions typical of mobile telecommunication.

The final report and the associated attachments are available as PDF-file in German.

Final report  106 kB
Attachment 1:	Gesundheitliche Auswirkungen hochfrequenter Strahlenexposition - ein Überblick  10 kB
Attachment 2:	Kohortenstudien zu den gesundheitlichen Effekten einer Exposition mit hochfrequenten elektromagnetischen Feldern  81 kB
Attachment 3:	Mögliche Einflussbereiche hochfrequenter elektromagnetischer Felder auf Gesundheit und Befinden  55 kB
Attachment 4:	Ausgewählte Literatur zur Expositionserfassung  18 kB
Attachment 5:	Literaturdatenbank  1,09 MB

Conclusions

On the basis of this feasibility study, the Federal Office of Radiation Protection (BfS) decided not to carry out any cohort studies on persons highly exposed to high frequency. Instead, a cohort study on mobile phone users among the general public is considered. Though exposures may be low, this study could directly answer the question of whether there are health risks from mobile telecommunication. Because the exposures are low, very large cohort studies will be necessary. This is only possible by participation in an international cohort study of mobile phone users.