A large multi-center study on cell phones and brain tumors was published this week, involving Japan, Canada and several European countries. Did this study answer the question once and for all about the potential connection between cell phone use and brain tumors? No it did not!

What is the science? 1. Radiofrequency waves from cell phones have previously been studied in test tubes and not found to cause pre-cancerous changes, though there is some concern about the heat generated by cell phones.

2. Previous multi-center trials, including one in Denmark have not proven a cause and effect between cell phones and brain tumors.

3. The current study, just published in the International Journal of Epidemiology, and performed by the International Agency for Research on Cancer (a division of the World Health Organization), is the largest study done yet, looking at over 12,000 people, over 5,000 with brain tumors - gliomas (malignant) and meningioma (benign) and it concludes that there is NOT a cause and effect between cell phone use and brain tumors - though it doesshow an increased risk in the highest use group (more than 30 minutes per day) on the same side of the face.

What are the flaws of the study? 1. Conflict of interest - 25 percent of money from cell phone companies, and was hyped by the Mobile Manufacturers Forum.

2. The results are out of date since we use cell phones much more now (this study looked at brain tumors diagnosed between 2000 and 2004 and looked at exposure in the 1990s).

3. I am not crazy about the study design. It uses interviews and expects people with brain tumors to look back on their cell phone use, when everything may be a blur when you have a brain tumor.

4. The study lumps meningioma and glioma - benign and malignant - together, even though the causes are totally different.

5. There is no inclusion of children, though this group is extremelyimportant because of their developing brains.

THE BOTTOM LINE:The jury on cell phones and brain cancer is still out, though it makes sense to limit prolonged use and to use headsets. The U.K. has launched a much bigger study, looking at 250,000 people over 20 to 30 years, but may still not show cause and effect. The numbers of brain tumors are too small to make a connection easily.

Dr. Marc Siegel is an internist and associate professor of medicine at the NYU School of Medicine. He is a FOX News medical contributor and writes a health column for the LA Times, where he examines TV and movies for medical accuracy. Dr. Siegel is the author of a new ebook: Swine Flu; the New Pandemic. Dr. Siegel is also the author of "False Alarm: The Truth About the Epidemic of Fear"and "Bird Flu: Everything You Need to Know About the Next Pandemic."Read more at www.doctorsiegel.com

Dr. Marc Siegel, a practicing internist, joined FOX News Channel (FNC) as a contributor in 2008..