By David Liu Ph.D. and editing by Elizabeth Hutchinson

Tuesday May 31, 2011 (foodconsumer.org) -- The International Agency for Research on Cancer, a cancer research agency of the World Health Organization, announced today that cell phones are a possible human carcinogen, and that its classification indicates that it can be as dangerous as cancer-causing agents pesticide DDT and car exhaust.

Dr. L Hardell and colleagues from University Hospital in Örebro, Sweden published a study in the May 2011 issue of the International Journal of Oncology that confirms that use of cell phones may increase the risk of a type of brain cancer called glioma.

Most of the previous studies that have linked the use of cell phones with the increased risk of brain cancer were conducted by Hardell and colleagues. His studies are considered to be of high quality by researchers in the field including Dr. Joel M. Moskowitz, director of the UC Berkeley Center for Family and Community Health. Dr. Moskowitz himself conducted studies and found similar associations.

The current study was based on data from three case-control studies that showed those who had used cell phones for ten or more years had their risk of the commonest type of glioma, astrocytoma, increased by 170 percent. The increase in the risk was 70 percent in those who used cordless phones.

The highest risk was found among those who started using wireless phones before they reached the age of 20. Of these subjects, cell phone users were 390 percent more likely to be diagnosed with astrocytoma, and cordless phone users were 290 percent more likely to suffer from that type of brain cancer.

Hardell et al. concluded that men and women who used cell phones for a longer period, or more accumulative hours, and those who started using wireless phones before the age of 20 years were at highest risk for the brain cancer astrocytoma.