CORAL GABLES, FL - FEBRUARY 10: Julie Bennink makes a phone call on her new iPhone that she had just purchased at a Verizon Wireless stores after they started selling the smart phone on February 10, 2011 in Coral Gables, Florida. AT&T had previously had a monopoly on selling the iPhone since 2007. (Photo by Joe Raedle/Getty Images)
Cell phone use changes activity in the area of the brain closest to the phone while it's on, according to a new study, but it's unclear whether it's harmful.
The study, published online in the Journal of the American Medical Association, found that brain glucose metabolism was "significantly higher" in the area closest to the cell phone antenna after 50 minutes of use.
The study, conducted on 47 healthy participants between January 1 and December 31, 2009, was started in response to concerns over both the possible harmful long-term effects of cell phone use on the brain -- like cancer -- and the possible short-term, incremental changes in brain function related to cell phone frequency.
"In healthy participants and compared with no exposure, 50-minute cell phone exposure was associated with increased brain glucose metabolism in the region closest to the antenna," the study concluded. The findings are still of "unknown clinical significance," but Dr. Henry Lai, one of the study's authors, said he hoped it would mark the beginning of expanded research on the health effects of cell phone use.