The title of this diary is also the headline of this article in Sunday's New York Times magazine. The writer, Siddhartha Mukherjee, manages to take the various complex methodologies of answering this question of the danger of cell phone use, and treat it like an episode of CSI, but one that is investigated throughout the world over many decades.
As someone who studied epidemiology at Columbia University, where the writer teaches, I know the difficulties of such investigations. Epidemiology, the study of incidence of disease in large populations is only one method, to be augmented by in vivo animal studies, and in vitro studies of the action of the radiation from cell phones on individual somatic biological cells. The evidence from each of these modalities is evaluated to try to find a consistency of results.
This is from the article:
Brain cancer is rare: only about 7 cases are diagnosed per 100,000 men and women in America per year, and a striking increase, following the introduction of a potent carcinogen, should be evident. From 1990 to 2002 — the 12-year period during which cellphone users grew to 135 million from 4 million — the age-adjusted incidence rate for overall brain cancer remained nearly flat. If anything, it decreased slightly, from 7 cases for every 100,000 persons to 6.5 cases (the reasons for the decrease are unknown).
But then there were these anomalous findings
In 2010, a larger study updated these results, examining trends between 1992 and 2006. Once again, there was no increase in overall incidence in brain cancer. But if you subdivided the population into groups, an unusual pattern emerged: in females ages 20 to 29 (but not in males) the age-adjusted risk of cancer in the front of the brain grew slightly, from 2.5 cases per 100,000 to 2.6
The overwhelming evidence is that cell phones do not cause brain cancer, but that does not end the controversy. When someone dies from such cancers, and the person has been using cell phones, and article have raised the issue, nothing can convince their loved ones that this was not the cause of the tragedy.
Here was my comment to the Times on the article:
An important side issue is the reporting of scientific experiments and research by the mass media. Few reporters or editors have more than a rudimentary understanding of these fields are especially weak in inferential statistics.
The term "significant" has two distinct meanings. The common one is "a meaningful difference," for example several inches in a person's height. The statistical meaning refers to the probability of the difference not being random, and can be only a fraction of an inch with a large enough sample.
So the public is bombarded with reports of studies that show a significant improvement in a disease with a given treatment, or a significant increase in incidence under certain exposures. And, of course, it is the most counter intuitive, the most frightening or most hopeful research that reaches the public, not the most scientifically rigorous.
The paradoxes of incidence of brain cancer and length of time on the phone can be explained by the very multiplicity of categories examined. As these multiply, especially in an area of great interest such as this, spurious "significant" findings are certain to be found. But, in the absence of replication or theoretical explanation the findings are meaningless.
The public is whipsawed, and policy which must be responsive to the electorate, becomes distorted.
For all who are interested in science, the media or how to discern meaningful research from that which sells papers, this article should be required reading.