A 2014 Swedish study involving 1498 malignant brain tumor patients and 3,530 controls (people without a brain tumor) found an increased risk of malignant brain tumor associated with long-term use of cell phones and cordless phones. The study analyzed data from two previous studies with patients diagnosed between 1997-2003 and 2007-2009 in Sweden. The pooled analysis showed a clear trend of higher risk with longer wireless phone use. Specifically, the risk was 3 times higher for people who used wireless phones for 25 years or longer. The results resonate with a 2014 French study which found that heavy cell phone users (with 896 hours or more cumulative call time, or about half an hour daily use for 5 years) were 2-3 times more likely to develop a glioma (the most common type of malignant brain tumor), compared to non-regular users.