Study type: Epidemiological study (observational study)

Has the incidence of brain cancer risen in Australia since the introduction of mobile phones 29 years ago? epidem.

Published in: Cancer Epidemiol 2016; 42: 199-205

Aim of study (acc. to author)

The association between mobile use coverage and brain cancer incidence was investigated in a trend study in Australia.

Further details

The observed incidence rates were compared to expected calculated incidence rates to illustrate the purported effect of mobile phones on brain cancer incidence. Estimated expected age specific incidence rates (4 groups: 20-39, 40-59, 60-69, 70-84 years) were calculated assuming a 10-year latency period and a relative risk of 1.5 in ever-users of mobile phones (published in Hardell et al., 2011) and a relative risk of 2.5 in a proportion of heavy users with more than 896 h cumulative use (19% of all users), published Morgan et al. (2015).

Endpoint/type of risk estimation

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

Exposure

Assessment

Population

Conclusion (acc. to author)

Overall, 19,858 male and 14,222 females were diagnosed with brain cancer in Australia between 1982 and 2012.
Age-adjusted brain cancer incidence rates have risen slightly in males but were stable over 30 years in females and are higher in males (SIR 8.7 per 100,000; CI 8.1-9.3) than in females (SIR 5.8 per 100,000: CI 5.3-6.3).
Assuming a causal RR of 1.5 and 10-year lag period, the expected incidence rate in males in 2012 would be 11.7 per 100,000 and in females 7.7 per 100,000; 1434 cases observed vs. 1867 expected cases in 2012. Assuming a causal RR of 2.5 among heavy users gave 2038 expected cases.
Significant increases in brain cancer incidence were observed (in keeping with modelled rates) only in those aged ≥ 70 years (both sexes), but the increase in incidence in this age group began from 1982, before the introduction of mobile phones. Modelled expected incidence rates were higher in all age groups in comparison to what was observed.
The authors conclude that the observed stability of brain cancer incidence in Australia between 1982 and 2012 in all age groups, except in those over 70 years compared to increasing modelled expected estimates, suggests that the observed increases in brain cancer incidence in the older age group are unlikely to be related to mobile phone use. They hypothesize that the observed increases in brain cancer incidence in Australia are related to the advent of improved diagnostic procedures (e.g. computed tomography) in the early 1980s.

Limitations (acc. to author)

This is an ecological trends analysis, with no data on individual mobile phone use and outcome.

Study funded by

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