Epidemiological study (observational study)

Cellular telephones and cancer--a nationwide cohort study in Denmark.

Published in: J Natl Cancer Inst 2001; 93 (3): 203-207

Aim of study (acc. to author)

A nationwide retrospective cohort study of cancer incidence was conducted in Denmark of all cellular telephone subscribers from 1982 through 1995.

Further details

Cellular telephone users were identified from subscriber lists of two Danish operating companies. The cancer incidence among the users was determined by linkage with the Danish Cancer Registry.

Endpoint/type of risk estimation

Type of risk estimation:
  • incidence
(standardized incidence rate (SIR))

Exposure

Assessment

Exposure groups

Group 1 total subscriber
Group 2 time since first subscription to a cellular phone service: < 1 year
Group 3 time since first subscription to a cellular phone service: 1-4 years
Group 4 time since first subscription to a cellular phone service: ≥ 5 years
Group 5 age at entry: 0-49 years
Group 6 age at entry: 50-64 years
Group 7 age at entry: ≥ 65 years
Group 8 cellular phone system used: analog
Group 9 cellular phone system used: analog and digital
Group 10 cellular phone system used: digital
Group 11 duration of digital subscription: < 1 year
Group 12 duration of digital subscription: 1-2 years
Group 13 duration of digital subscription: ≥ 3 years

Population

  • Group:
    • men
    • women
  • Age: ≥ 18 yr
  • Characteristics: cellular telephone subscribers
  • Observation period: January 1982 - December 1995
  • Study location: Denmark
  • Data source: Danish Cancer Registry
  • Exclusion criteria: corporate customers

Study size

Total 723,421
Eligible 420,095
Other: 1,128,493 peron-years of follow-up
Statistical analysis method:
  • Miettinen exaxt method

Conclusion (acc. to author)

The results showed no increased risk for all cancers, brain tumors, leukemia, or tumors of the salivary glands, the sites of a priori interest. No association between cancer incidence and cellular phone subscription was found with the latency, age at first subscription, analog or digital cellular phones use, and duration of subscription.

Limitations (acc. to author)

No conclusions can be drawn for long-term users, since only 5.1% of the cohort members had a cellular phone subscription for more than 5 years.

Study funded by

  • Danish Cancer Society
  • International Epidemiology Institute, Maryland, USA
  • Sonofon, Denmark
  • TeleDanmark Mobil (TDC Mobil), Denmark

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