Case–control study of the association between the use of cellular and cordless telephones and malignant brain tumors diagnosed during 2000–2003

We performed a case–control study on the use of cellular and cordless telephones and the risk for brain tumors diagnosed during 2000–2003. We report the results for malignant brain tumors with data from 317 cases (88%) and 692 controls (84%). The use of analog cellular phones yielded odds ratio (OR) of 2.6 and a 95% confidence interval (CI) of 1.5–4.3, increasing to OR=3.5 and 95% CI=2.0–6.4 with a >10-year latency period. Regarding digital cellular telephones, the corresponding results were OR=1.9, 95% CI=1.3–2.7 and OR=3.6, 95% CI=1.7–7.5, respectively. Cordless telephones yielded OR=2.1, 95% CI=1.4–3.0, and with a >10-year latency period, OR=2.9, 95% CI=1.6–5.2. The OR increased with the cumulative number of hours of use and was highest for high-grade astrocytoma. A somewhat increased risk was also found for low-grade astrocytoma and other types of malignant brain tumors, although not significantly so. In multivariate analysis, all three phone types studied showed an increased risk.