Trends in brain cancers (glioma) in New Zealand from 1995 to 2020, with reference to mobile phone use

BackgroundSome case-control studies have suggested substantial increased risks of glioma in association with mobile phone use; these risks would lead to an increase in incidence over time.MethodsIncidence rates of glioma from 1995 to 2020 by age, sex, and site in New Zealand (NZ) recorded by the national cancer registry were assessed and trends analysed. Phone use was based on surveys.ResultsIn these 25 years there were 6677 incident gliomas, giving age-standardised rates (WHO world standard) of 6.04 in males, and 3.95 in females per 100,000. The use of mobile phones increased rapidly from 1990 to more than 50% of the population from about 2000, and almost all the population from 2006. The incidence of glioma from ages 10–69 has shown a small decrease over the last 25 years, during which time the use of mobile phones has become almost universal. Rates in the brain locations receiving most radiofrequency energy have also shown a small decrease. Rates at ages of 80 and over have increased.ConclusionThere is no indication of any increase related to the use of mobile phones. These results are similar to results in Australia and in many other countries. The increase in recorded incidence at ages over 80 is similar to that seen in other countries and consistent with improved diagnostic methods.