It is too soon for a verdict on the health risks from cellular telephones, especially in view of changing technology. From the Interphone project and some other large studies in progress, better information may emerge. Based on the epidemiological evidence available now, the main public-health concern is clearly motor vehicle collisions, a behavioural effect rather than an effect of radiofrequency exposure as such. Neither the several studies of occupational exposure to radiofrequencies nor the few of cellular telephone users offer any clear evidence of an association with brain tumours or other malignancies. Even if the studies in progress were to find large relative effects for brain cancer, the absolute increase in risk would probably be much smaller than the risk stemming from motor vehicle collisions. Cellular telephones affect the quality of our lives in myriad ways, for good and ill; the health risk is just one part of a picture that is slowly coming into focus.
Epidemiological evidence on health risks of cellular telephones