Monday, 17 June 2019

No increase in brain tumour rates in countries with first mobile networks

Nordic countries

The rates of the most common form of brain tumour did not increase in the countries first to launch mobile phone networks and with the most mobile phone users, a new study has found, which contradicts claims they are a possible cause of the disease.


The incidence of glioma did not increase in Nordic countries in the age groups who were most likely to be mobile phone users, scientists from the International Agency for Research on Cancer (IARC) and the Karolinska Institute found.


The paper published in Epidemiology in January looked at the rate of glioma in men and women aged 20 to 79 years between 1979 and 2008 to look for a trend that might indicate a link with the disease due to the rapid increased use of mobile phones during that time.


“People living in the Nordic countries were quick to adopt mobile phone technology and mobile phones have been used by a very large percentage of the population," Professor Maria Feychting of the Institute of Environmental Medicine at Karolinska Institute said.  


“All Nordic countries have cancer registries of a very high quality, which provide excellent opportunities for studying changes in the incidence of brain tumours.”


“Incidence rates were generally stable over the whole period, and increased gradually among older persons. A slight decrease in incidence rates was observed after the late 1980s among the younger men overall and in Denmark and Sweden, but not in Finland and Norway,” the researchers concluded.

Comparison with other studies

The researchers also looked for an increase in glioma incidence, which would explain the results of some earlier population studies. For example, the 13-nation Interphone study found while there was no increased risk of cancer overall, those who reported the top 10 per cent of phone use had an increased rate of glioma and this increase had a 98 per cent chance of showing up in their 30 year analysis if the risk was real.


Since no upward trend was found in the cancer statistics, it strongly challenges the validity of the increased risks reported in a few studies and therefore appear to be due to biases and errors, such as in self-reported mobile phone use, the researchers said.

“The present study shows that there has been no increase in glioma in the Nordic countries since the introduction of mobile phones, and that the risk increases reported in a few individual studies are inconsistent with the cancer statistics.”

The paper is an update of a previous study on the incidence of glioma in the Nordic countries. The analyses now cover the years up to 2008 and still show no sign of an increase in the disease in the age groups that have been using mobile phones. Similar trend analyses for the UK and the USA have also not seen increases.


Fast mobile phone adopters

Nordic countries were quick to adopt mobile phones and had the highest percentage of subscribers in the world, well above other developed nations such as Australia, the USA and the UK.
One of the first generation (1G) networks was the Nordic Mobile Telephone (NMT) network which was launched in Sweden and Norway in 1981, Denmark and Finland in 1982 and in Iceland in 1986. The world’s first 2G – digital GSM – network was launched in Finland in 1991.
The Nordic countries have had widespread mobile phone use for around 20 years.

Mobile phone subscribers per 100 inhabitants in 1997 

OECD graph

Source: OECD Communications Outlook 1999

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