A study by the European Union-funded INTERPHONE group and another led by L. Hardell, a Swedish epidemiologist, showed an increased risk (40-170 per cent) of developing glioma, a malignant brain cancer, in people who used a mobile phone for 30 minutes a day over ten years.The idea of mobile phone radiation increasing the risk of cancer was strengthened by two other studies. The Cerenat study, published in 2013, confirmed observations of the INTERPHONE and Hardell studies. And an animal study in 2015 showed cell phone radiation enhanced the carcinogenic effects of chemicals.