# Danish cohort study of mobile subscribers (2011 update)

> A nationwide cohort using subscription records rather than recall found no elevated brain tumour incidence among long-term subscribers, including those with 13 or more years of subscription.

- Canonical URL: https://emfbase.com/studies/danish-cohort-2011
- Collection: Research record
- Record id: `studies:danish-cohort-2011`
- Status: verified
- Last verified: 2026-08-12
- JSON: https://emfbase.com/api/studies/danish-cohort-2011

## Key values

- **Authors:** Frei P, Poulsen AH, Johansen C, et al.
- **Year:** 2011
- **Design:** cohort
- **Exposure studied:** Mobile phone subscription duration from operator records, Danish population
- **Place in the evidence base:** high
- **Primary document:** https://www.bmj.com/content/343/bmj.d6387

## Finding

No increased risk of tumours of the central nervous system among long-term subscribers.

## What it cannot establish

Subscription is a crude proxy for use: corporate subscriptions were excluded and non-subscribing users misclassified, both of which dilute any true effect. No data on call time or on which side of the head was used.

## Related records

- [INTERPHONE international case–control study (2010)](https://emfbase.com/studies/interphone-2010): The largest case–control study of mobile phone use and brain tumours found no overall increase in glioma or meningioma, with a raised glioma odds ratio confined to the highest decile of reported call time.

## Sources

- `danish-cohort-2011` BMJ (2011). *Use of mobile phones and risk of brain tumours: update of Danish cohort study*. https://www.bmj.com/content/343/bmj.d6387 — peer-reviewed, link checked 2026-08-12

Data licence: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Dataset version 2026.08.1. Retrieved from EMFBase, https://emfbase.com.

This record is reference data, not medical or legal advice. Regulatory limits, scientific guidelines and precautionary values are labelled separately and answer different questions.