L Hardell1; A Hallquist2; K Hansson Mild3; M Carlberg1; A Phlson4; A Lilja5
1 Department of Oncology, University Hospital, S-701 85 Örebro and Department of Natural Sciences, Örebro University, S-701 82 Örebro, Sweden; 2 Department of Oncology/Pathology, Karolinska Institute, Radiumhemmet, S-171 76 Stockholm, Sweden; 3 National Institute for Working Life, S-907 13 Ume and Department of Natural Sciences, Örebro University, S-701 82 Örebro, Sweden; 4 Department of Neurology, University Hospital, S-701 85 Örebro, Sweden; 5 Department of Neuroradiology, Karolinska Institute, S-112 35 Stockholm, Sweden
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Microwave exposure from the use of cellular telephones has been discussed in recent years as a potential risk factor for brain tumours. We included in a case-control study 1617 patients aged 20-80 years of both sexes with brain tumour diagnosed between 1 January 1997 and 30 June 2000. They were alive at the study time and had histopathologically verified brain tumour. One matched control to each case was selected from the Swedish Population Register. The study area was the Uppsala-Örebro, Stockholm, Linköping and Göteborg medical regions of Sweden. Exposure was assessed by a questionnaire that was answered by 1429 (88%) cases and 1470 (91%) controls. In total, use of analogue cellular telephones gave an increased risk with an odds ratio (OR) of 1.3 (95% confidence interval (CI) 1.02-1.6). With a tumour induction period of >10 years the risk increased further: OR 1.8 (95% CI 1.1-2.9). No clear association was found for digital or cordless telephones. With regard to the anatomical area of the tumour and exposure to microwaves, the risk was increased for tumours located in the temporal area on the same side of the brain that was used during phone calls; for analogue cellular telephones the OR was 2.5 (95% CI 1.3-4.9). Use of a telephone on the opposite side of the brain was not associated with an increased risk for brain tumours. With regard to different tumour types, the highest risk was for acoustic neurinoma (OR 3.5, 95% CI 1.8-6.8) among analogue cellular telephone users.
Key words: Benign; brain tumours; cordless telephones; malignant; mobile telephones; temporal area
L Hardell1; K Hansson Mild2; A Phlson3; A Hallquist4
1Department of Oncology, Örebro Medical Centre, S-701 85 Örebro and Department of Natural Science, Örebro University, S-701 82 Örebro, Sweden. 2National Institute for Working Life, S-907 13 Ume and Department of Natural Science, Örebro University, S-701 82 Örebro, Sweden. 3Department of Neurology, Örebro Medical Centre, S-701 85 Örebro, Sweden. 4Department of Oncology Pathology, Karolinska Institute Radiumhemmet, S-1 71 76 Stockholm, Sweden.
A case-control study on brain tumours included 233 patients aged 20-80 years and alive at the study time. They had histopathologically verified brain tumour and lived in the Uppsala-Örebro region (1994-1996) or the Stockholm region (1995-1996). Two matched controls to each case were selected from the Swedish Population Register. Two hundred and nine cases (90%) and 425 controls (91%) answered the questionnaire. Results are presented for the whole study group, as given here, and for malignant and benign tumours separately. For workers in the chemical industry the odds ratio (OR) was 4.10, 95% confidence interval (95% CI) 1.25-13.4 and laboratory workers OR 3.21, 95% CI 1.16-8.85. Radiotherapy of the head and neck region gave OR 3.61, 95% CI 0.65-19.9. Medical diagnostic X-ray of the same area yielded OR 1.64, 95% CI 1.04-2.58. Work as a physician gave OR 6.00, 95% CI 0.62-57.7. All three cases had worked with fluoroscopy. Ipsilateral (same side) use of a cellular telephone increased the risk of tumours in the temporal, temporoparietal and occipital areas, with OR 2.42, 95% CI 0.97-6.05 (i.e. the anatomical areas with highest exposure to microwaves from a mobile phone).
Key words: Brain tumours; medical X-ray investigations; mobile phones; radiotherapy.
Anssi Auvinen1; Maila Hietanen2; Ritva Luukkonen3; Riitta-Sisko Koskela3
From the 1Finnish Cancer Registry and STUK-Radiation and Nuclear Safety Authority, and 2Finnish Institute of Occupational Health, Department of Physics, and 3Department of Epidemiology and Biostatistics, Helsinki, Finland.
Background. Possible risk of cancer associated with use of cellular telephones has lately been a subject of public debate.
Methods. We conducted a register-based, case-control study on cellular phone use and cancer. The study subjects were all cases of brain tumor (N = 398) and salivary gland cancer (N = 34) diagnosed in Finland in 1996, with five controls per case.
Results. Cellular phone use was not associated with brain tumors or salivary gland cancers overall, but there was a weak association between gliomas and analog cellular phones.
Conclusions. A register-based approach has limited value in risk assessment of cellular phone use owing to lack of information on exposure.
Key words: brain neoplasms; salivary gland neoplasms; cellular telephones; radiofrequency fields
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