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| Autores McKenzie DR and Yin Y This study is a re-exploration of the apparent association between proximity to TV towers and the incidence of leukaemia, reported by Hocking and his colleagues (see summary elsewhere). An area in Sydney, NSW, Australia was examined. The incidence of acute lymphoblastic leukaemia (ALL) was no higher in the areas close to the towers than in the rest of NSW with the exception of one area, which contributed all the excess seen in Hocking's study.. In this higher incidence area, the highest leukaemia rates occurred in the years before there was exposure to TV towers. In two other high exposure areas, the incidence was similar to those for the less exposed areas. No dose-response relationship could be seen. In particular, the incidence of ALL was different in areas with similar exposure to radiofrequency broadcast radiation.
This study differs from Hocking's in several respects: ALL was chosen
because most cases occur in the first five years of life, so that there
is greater confidence that the ALL incidence can be linked to environmental
factors at the residential site (if linkage exists), and occupational
exposure is not relevant, as it would be with an older population. Second,
smaller areas were examined. Third, all areas in proximity to the towers
were studied (in Hocking's study, some were excluded on socioeconomic
grounds, despite the fact that there is little evidence that socioeconomic
status influences ALL in NSW). McKenzie and colleagues suggest that the
one area with the excess ALL cases needs further investigation, and that
infectious or genetic factors might be relevant. |
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