An international prospective cohort study of mobile phone users and health (Cosmos): design considerations and enrolment.
BACKGROUND
There is continuing public and scientific interest in the possibility that exposure to radiofrequency (RF) electromagnetic fields (EMF) from mobile telephones or other wireless devices and applications might increase the risk of certain cancers or other diseases. The interest is amplified by the rapid world-wide penetration of such technologies. The evidence from epidemiological studies published to date have not been consistent and, in particular, further studies are required to identify whether longer term (well beyond 10 years) RF exposure might pose some health risk.


METHODS
The "Cosmos" study described here is a large prospective cohort study of mobile telephone users (ongoing recruitment of 250,000 men and women aged 18+ years in five European countries - Denmark, Finland, Sweden, The Netherlands, UK) who will be followed up for 25+ years. Information on mobile telephone use is collected prospectively through questionnaires and objective traffic data from network operators. Associations with disease risks will be studied by linking cohort members to existing disease registries, while changes in symptoms such as headache and sleep quality and of general well-being are assessed by baseline and follow-up questionnaires.


CONCLUSIONS
A prospective cohort study conducted with appropriate diligence and a sufficient sample size, overcomes many of the shortcomings of previous studies. Its major advantages are exposure assessment prior to the diagnosis of disease, the prospective collection of objective exposure information, long-term follow-up of multiple health outcomes, and the flexibility to investigate future changes in technologies or new research questions.
Schüz
Joachim
J
Institute of Cancer Epidemiology, Danish Cancer Society, Copenhagen, Denmark.
Elliott
Paul
P
Auvinen
Anssi
A
Kromhout
Hans
H
Poulsen
Aslak Harbo
AH
Johansen
Christoffer
C
Olsen
Jørgen H
JH
Hillert
Lena
L
Feychting
Maria
M
Fremling
Karin
K
Toledano
Mireille
M
Heinävaara
Sirpa
S
Slottje
Pauline
P
Vermeulen
Roel
R
Ahlbom
Anders
A
D000293:Adolescent; D000328:Adult; D000368:Aged; D001932:Brain Neoplasms / Q000453:epidemiology*; D040421:Cell Phone / Q000706:statistics & numerical data*; D015331:Cohort Studies; D004574:Electromagnetic Fields / Q000009:adverse effects; D005060:Europe; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D011840:Radiation, Nonionizing / Q000009:adverse effects; D018570:Risk Assessment; D011795:Surveys and Questionnaires; D055815:Young Adult