Stang A, Anastassiou G, Ahrens W, Bromen K, et al.

Stang and colleagues in Germany conducted a study designed to explore the association between RF radiation and uveal melanoma, a rare tumour of the eye. Cases were identified in two ways; as part of a multinational population-based study, and in a hospital-based study. Controls for the former were selected randomly from residence lists, and for the hospital study from patients with other eye diseases. A total of 118 cases and 475 controls were identified. Interviews with the participants used a structured questionnaire and covered a variety of topics, including exposure to electromagnetic radiation. Occupational exposure to RFR devices was assessed, by asking: "Did you use radio sets, mobile phones or similar devices at your workplace for at least several hours per day?" Those who answered "yes" were asked further questions about years of exposure and the way the RFR device was carried. Those exposed to radio sets or mobile phones had an OR of 3.0. Those "possibly/probably/certainly" exposed to mobile phones had an OR of 2.9 (confidence intervals 1.0-7.9), but this was based on only 7 cases.

The authors speculated that a possible explanation for an increased risk of uveal melanoma could be that if RFR decreased the amount of melatonin produced in the eye, this would promote the development of the tumour.

Stang and colleagues acknowledge that their study has several limitations. In particular, details of the exposure to RFR are limited.

In an accompanying editorial in the same issue of the journal, Inskip (Epidemiology 2001;12:1-4) criticises the study in several ways. He regrets the lack of details about exposure to ultraviolet radiation (which has been linked to uveal melanoma), to other sources of RFR, or to other occupational exposures. He also comments about the lack of information about the intensity of exposure to the RF sources discussed in the paper. He concludes "given the small size of their study, the relatively crude exposure assessment, the absence of attention to UVR exposure or other possible confounding variables, and limited support in the literature, a cautious interpretation of their results is indicated."