Gousias K, Markou M, Voulgaris S, Goussia A, Voulgari P, Bai M, Polyzoidis K, Kyritsis A, Alamanos Y. 2009. Descriptive epidemiology of cerebral gliomas in northwest Greece and study of potential predisposing factors, 2005-2007. Neuroepidemiology. 33(2):89-95.
Cerebral gliomas are the most frequently diagnosed brain tumors and have an extremely poor prognosis. However, little is known about how these types of tumors arise. Some studies have suggested that they are associated with older age, male sex, and Caucasian race while the roles of mobile phone use, alcohol consumption, smoking, and physical head trauma are controversial.
The aim of this study was to investigate the epidemiological and clinical characteristics of glioma patients and to compare risk factors with control patients in a defined area of Northwest Greece.
Newly diagnosed cases of cerebral glioma between June 2005 and May 2007 seen at one of 7 area hospitals were eligible for inclusion in the study. The diagnosis was confirmed by biopsy in 91% of patients and by clinical criteria in the remaining patients. Controls were patients without brain diseases seen in the Neurological Department of one of the participating hospitals. For every case recruited to participate, two controls of the same age, gender, and district of residence were recruited. All subjects were interviewed and asked about alcohol consumption, smoking, use of mobile phones (time of start, intensity of use (minutes spent talking per day by number of years of use), and hands-free use), and history of severe brain trauma.
Over the study period, 56 cases of glioma were diagnosed among the population of approximately 500,000, giving an incidence rate of 5.73/100,000 per year. The rate among males was 5.97/100,000 per year (29 cases) and the rate for females was 5.50/100,000 per year (27 cases). The case-control study included the first 41 of the 56 cases of glioma, and 82 controls. There was no significant association between glioma and alcohol consumption, smoking, history of cranial trauma, and mobile phone use (in minute-years).
Interpretation and Limitations
There is significant worldwide geographical variation in the incidence of gliomas, which is likely related to differences in genetic, racial, and environmental factors. The incidence rate reported in this study is higher than in other white populations, which may be due to undetermined environmental factors. Alternatively, they may reflect global trends of increasing incidence of gliomas. Some gliomas may not have been recorded by the study group, especially in rural areas where health services are less developed. Gliomas occurring in elderly persons were most likely to have been missed, since they could easily have been misdiagnosed as a stroke in the absence of a radiological examination. Most studies have found no relationship between mobile phone use and gliomas, although there may be an association with long-term use, which the authors were not able to detect.
A high incidence of gliomas and glioblastoma was found in Northwest Greece. There was no association with lifestyle factors including the use of mobile phones.