Laid to Rest

It is time to lay the myth that cellphone use causes cancer to rest. In a Scandinavian study not yet published (but available online), the authors have gathered all the cancer registry data from four countries with similar registry requirements (Denmark, Finland, Norway and Sweden) and have determined the trends in brain tumour incidence over the past 35 years. The result? There is absolutely no change in the incidence trends of most brain tumours over the past 35 years. Ergo, cell phones do not increase your chance of brain tumours (otherwise you would have seen a nice “hockey stick” over the last decade).

The sheer size of this study means that even rare tumours like those of the brain can be effectively monitored. Brain tumours usually have incidences of 5 -15 per 100,000 population and one of the biggest problems with cell phone studies so far is that the actual numbers of brain tumours have been too small to draw any real inferences.

As the graphs from this study demonstrate, there has been no real increase in incidence or increased rate of increase of incidence in brain tumours over the past 35 years. There is only one of three possible conclusions one can draw from this data:

1. It takes longer than 20 years (the length of time that cell phones have been used) to develop tumours from cell phone use. This is possible, but not hugely plausible as one would have expected some of the more aggressive cancers to be manifesting by now.
2. The rate of increase is too small even for this large population study to pick up. In which case we are dealing with a very small increase in a rare cancer i.e. a negligible risk.
3. Cellphone use simply does not cause cancer – by far the likeliest conclusion.

It should also be noted that this data is too broad to pick out subsets. You cannot tell, for instance, if  cellphone use for more than an hour a day in children under 12 causes an increase in gliomas. Given the rarity of gliomas, I would think this kind of data would be almost impossible to ascertain. In the absence of less specific data, I would accept this study as being reasonably definitive on the issue. Given that it corroborates the findings of the excellent Danish Cohort Study, I think this issue can now be laid to rested.

Interestingly, the latest findings of the Danish Cohort Study include a possible increase in the incidence of migraine and vertigo with cell phone use and a possible decrease in Alzheimer’s disease. Unfortunately, it is very likely that the decrease in Alzheimer’s is secondary to confounding effects such as patients with early dementia avoiding cellphone use and the bias towards a more affluent, healthier community with a lower natural incidence of Alzheimer’s (this is Denmark, we are talking about).

On the other hand, interaction with people has been shown to have a protective effect against Alzheimer’s, so maybe there is a direct causation after all.

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