Study type: Epidemiological study (observational study)

Use of mobile phones and risk of brain tumours: update of Danish cohort study. epidem.

Published in: BMJ 2011; 343: d6387

Aim of study (acc. to author)

A follow-up of a nationwide cohort was performed to investigate the risk of brain tumors among Danish mobile telephone subscribers from 1990 through 2007.

Further details

Further results of this Danish cohort study are published in Johansen et al (2001), Schüz et al (2006), and Schüz et al (2011).
To obtain information on highest attained education and disposable income, the data were linked to a cohort study on social inequality and cancer.

Endpoint/type of risk estimation

Type of risk estimation: (incidence rate ratio)

Exposure

Assessment

Exposure groups

Group Description
Reference group 1 non-subscribers
Group 2 subscribers
Group 3 subscribers: 1 - 4 years of subscription
Group 4 subscribers: 5 - 9 years of subscription
Group 5 subscribers: ≥ 10 years of subscription
Group 6 subscribers: 10 - 12 years of subscription
Group 7 subscribers: ≥ 13 years of subscription

Population

Study size

Type Value
Total 358,403
Other:

3.8 million person years, male subscribers providing 3.2 million person years

Statistical analysis method: ( adjustment: )

Conclusion (acc. to author)

No overall increased risk of brain tumors or for all cancers combined associated with use of mobile phones was observed. No dose-response relation was found with regard to years of subscription or to the anatomical site of the glioma.
The authors concluded that in this update of a large nationwide cohort study of mobile phone use, there was no increased risk of brain tumors, providing little evidence for a causal association.

Limitations (acc. to author)

The authors noted that a limitation of the study is potential misclassification of exposure. No information on the actual amount of mobile phone use was available.

Study funded by

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