Recent years have brought much public worry about the possible link between cell phones and brain tumors. And scientific studies have done little to lessen people’s fears, since the results have been frustratingly inconclusive.

Many experts have been slow to jump on the bandwagon, since plenty of other studies have shown no link, or an unconvincing one.

Just a few months ago a large-scale study reported that the risk of two types of brain tumors (glioma and acoustic neuroma) was double in cell phone users over the period of ten years — the authors even volunteered a number of tips to help users reduce their risk. The World Health Organization (WHO) then stated that cell phones are "possibly carcinogenic to humans." Still, many experts have been slow to jump on the bandwagon, since plenty of other studies have shown no link, or an unconvincing one.

Now, another large scale study reports no increased risk in cell phone users over the 10 to 15 years that people have been using them. The authors reviewed a previously published study that quizzed 13,000 people about their cell phones use over a period of 10 years.

The authors conclude that "[a]lthough there remains some uncertainty, the trend in the accumulating evidence is increasingly against the hypothesis that mobile phone use can cause brain tumors in adults." They do say, however, that "[m]ethodological deficits limit the conclusions that can be drawn" from the study, which was funded by the cell industry. One problem was that the study asked people to recall their behavior (here, cell phone use) in previous years, which is always tricky in scientific studies because the accuracy of participants recall can be questionable.

So, whether this new study will affect how the public, the media, and the scientific community view cell phone safety remains to be seen. The authors point out that because of the relative recency of cell phone use, it may take several more years, or decades, before we know more. We’ll be sure to stay tuned as more research in this area unfolds.

The study was carried out by researchers at the British Institute of Cancer Research, and published in the July 1, 2011 online issue of Environmental Health Perspectives.