Using your phone for 15 hours a month over five years doesn’t sound like much, but that’s the amount of time scientists say can increase your risk of developing certain types of brain cancers. Despite previous studies that have debunked the connection between cellphones and cancer, Agence France-Presse reports that cell phone uses are exposing themselves to a greater risk of developing glioma and meningioma tumors, compared to people who don’t use their phone as much. The report is based on a new study published in British journal Occupational and Environmental Medicine.

The study is one in a long line of reports on possible links between cancer and cell phone use, and one that will not settle question decisively.  In 2011, a study for the Institute of Cancer Research found “no convincing evidence of a link” between cellphone use and brain tumors, but did say that long-term health damage was still a possibility. Another study by the World Health Organization's International Agency for Research on Cancer said that cell phone-emitting radiofrequency electromagnetic fields are “possibly carcinogenic to humans,” and said they increased the risk of glioma. A 2011 National Institutes of Health study discovered that cell phone use could change brain activity, which could be sped up after less than an hour of cellphone use, but long-term health risks and detrimental side-effects couldn’t be determined. The official word on the NIH website is that “more research is needed.”

The new French study looked at 253 cases of glioma and 184 cases of meningioma. When they were compared to a group of healthy people, cell phone use increased the risk of developing both types of brain cancer, especially among phone-heavy jobs like sales. Oddly enough, the study found that if cancer does occur, it’s on the opposite side of the brain to the side where the phone is normally being used; previously it was believed the cancer developed on the same side.

Researchers said that one of the main difficulties in finding a possible link is getting an accurate idea of phone use in real life by filtering out other cancer-causing behaviors like cigarette smoking. Rapidly changing cell phone technology was also taken into account. So the answer for now is... there is no answer. At least not one to rest the case.