V Spinelli, Chinot O, Cabaniols C, Giorgi R, Alla P, Lehucher-Michel MP. Occupational and environmental risk factors for brain cancer: a pilot case-control study in France. La presse Médicale. Dec 4, 2009. Ahead of print.
The incidence of malignant primary brain tumours has increased in the industrialized countries during the past 3 decades. This increase can be explained by improvements in diagnostic methods, but the role of environmental factors, both occupational and non-occupational, cannot be excluded and must be further examined.
The objective of this pilot study in southeastern France was to estimate chemical and physical risk factors for malignant primary brain tumours.
The study included all new adult malignant primary brain tumours cases (n=122) diagnosed in 2005 in the major hospitals for treatment of brain cancer in the western part of the Provence-Alpes-Côte d’Azur area. Age and gender matched controls (one for each case) were patients hospitalized for reasons unrelated to cancer and randomly selected from the neurosurgery department of the same hospital. An occupational physician collected information on suspected risk factors for malignant primary brain tumours through a face-to-face interview at the hospital, using a standardized questionnaire. Information was collected on various non-occupational exposures and on occupational history during the entire lifetime.
No significant association was observed for occupational chemical exposures. Of the 20 studied chemical exposures during leisure-time activities, significant malignant primary brain tumours risk was associated only with glue use (Odds Ratio(OR): 17.58; 95% Confidence Interval(CI): 1.75-176). Significant inverse association was observed for living near (<500 metres) cell phone towers (OR: 0.49; 95% CI: 0.26-0.92). No association was observed between cumulative cell phone use (in hour-years) and malignant primary brain tumours risk: the ORs using “no phone” as a reference category were 0.86 (95% CI: 0.30-2.44); 1.45 (95% CI: 0.75-2.80) and 1.07 (95% CI: 0.41-2.82) for ≤4; 4-36 and ≥36 hour-years of cell phone use, respectively.
The assessment of occupational and non-occupational risk factors for malignant primary brain tumours in this study could be affected by the small sample size and by recall bias. Awareness of the interviewer about the participants’ status could lead to different interviewing styles between cases and controls. The lack of association between malignant primary brain tumours risk and cell phone use is in line with the results of other studies. However, the assessment in this study was limited by measurement of the length of telephone subscriptions rather than actual time of use. Chemical or physical exposures near the participants’ homes (<500 m), in particular exposure from cell phone towers, were assessed imprecisely: some participants were unable to respond to this question, precise distance and duration of exposure could not be evaluated.
The risk of malignant primary brain tumours was not associated with cumulative duration of cell phone use and was inversely associated with living near cell phone towers. Because of the study limitations, no definitive conclusions can be made on the basis of these results.