Cell phones and cancer have yet to be definitively linked, but a recently launched study will take a serious look into the long-term effects of cell phone usage on the human body. The Cohort Study of Mobile Phone Use and Health (COSMOS) will follow 200,000 mobile phone users in five countries over 30 years, monitoring their health for higher risk of brain cancer, head tumors and salivary gland cancer. The radiation risk seems plausible -- a 2009 World Health organization found that long-term mobile users had a higher risk of cancer, a 2008 American Journal of Epidemiology study suggested a link between big-time cell users and salivary gland cancer, and a 2006 study in Sweden indicated a 240% risk increase for head tumors on the side of the head used most often for talking. Thirty years is a long time to wait for results of this big study, so in the meantime maybe use that land line for long calls!