The largest study to date to determine whether cell phones increased risk for getting cancer found no link, yet the results do not establish the devices are "safe."

According to a Danish study published in the British Medical Journal that monitored more than 350,000 cell phone users in Denmark over a period of 18 years, there is no link between the devices and increased risks of tumors of the central nervous system.

"While this study does not show any association, it does not establish "safety" -- that is, the absence of risk," Dr. Jonathan Samet who lead a panel of experts on the issue at the World Health Organization, told WebMD.  "This is a useful addition to the literature, and we need more studies of high quality."

The new research matches studies from the U.S. Food and Drug Administration, the U.S. Centers for Disease and Control Prevention and the Federal Communications Commission which have found no evidence that cell phones increase risk of cancer.

However, organizations like MobileWise, who sustain that cell phones pose cancer and genetic health damage, criticised the study as "seriously flawed" and said it offered "false reassurance."

MobileWise said the Danish study is flawed because it considered subscription holders instead of users.

"The report itself states that a limitation of the study is potential misclassification of exposure…Subscription holders who are not using their phone will erroneously be classified as exposed and people without a subscription but still using a mobile phone will erroneously be classified as unexposed,” the group said.

Epidemiologist Dr Devra Davis of the Environmental Health Trust in the US says the ‘new’ study is only an extension of one already published by the Danish team two years ago, MobileWise said.

Not only was it widely criticized at the time, but it was rejected by the World Health Organization as unreliable when they did a review of studies in May, she added. The WHO panel voted almost unanimously to classify mobile radiation as “possibly carcinogenic.”

The U.S. agencies mentioned above have acknowledged the need for more research about the health risks on people using mobile phones.

More than 87 percent of people in the United States had a mobile phone in 2008.