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EMF Study
(Database last updated on Mar 27, 2024)

ID Number 185
Study Type Epidemiology
Model 30-300 MHz (VHF) FM and TV broadcast tower exposure to residents in NSW Australia and correlation with cancer in children and adults.
Details

Human subjects living in three "inner area" municipalities (n =135,000) immediately surrounded by 3 TV towers in a triangular area ~1.5 km on a side, and for 6 adjacent "outer area" municipalities (n =450,000), were analyzed for an association between leukemia & lymphoma incidence (from 1972-1990) and proximity to the transmitters. The broadcast signals were 100-kW AM-modulated video and 10-kW FM- modulated audio on carrier frequencies ranging from 63 to 215 MHz, and one signal at 500 MHz. The calculated power density in the inner area ranged from 8.0 uW/cm2 near the towers, 0.2 uW/cm2 at distance of 4 km, and to 0.02 uW/cm2 at a distance of 12 km. There was a non-significant increase in adult leukemia incidence, and a significant increase in childhood leukemia incidence (OR = 1.58, CI 1.1-2.3). The authors concluded from the data that there was an association between proximity to TV towers and childhood leukemia incidence and mortality. There was no excess of brain tumors in adults or children. In a follow-on study, the authors report a significant decreased 5-yr and 10-yr survival for acute lymphocytic leukemia in the inner ring (55%, 33%) vs. the outer ring (71%, 62%). The adjusted mortality OR = 2.1; 95% CI 1.1, 4.0).

Findings Effects
Status Completed With Publication
Principal Investigator Private Consultant in Occup'l Medicine, Australia - bruhoc@connexus.apana.org.au
Funding Agency Private/Instit.
Country AUSTRALIA
References
  • Hocking, B et al. Arch Environ Health, (2003) 58:560-564
  • Hocking, B et al. Med. J. Australia, (1996) 165:601-605
  • Hocking, B et al. American journal of epidemiology., (1998) 147:90-91
  • Hocking, B et al. Australian and New Zealand journal of public health., (1999) 23:104-105
  • Hocking, B The Medical journal of Australia., (2005) 182:364-365
  • Hocking, B Occupational and environmental medicine., (1998) 55:288-
  • Comments

    In a review of the data (McKenzie et al., 1998, Australian and New Zealand J Pub Health 22:360-367), the author (McKenzie) points out that the increased incidence and mortality are the result of a single “local government area" (LGA) in Lane Cove (1.46 uW/cm2), New South Wales. When the two remaining close proximity LGA’s (Willoughby, 1.40 uW/cm2 and North Sydney, 0.66 uW/cm2) are analyzed alone or together, they have incidence and mortality rates similar to the main population of NSW. If all three high exposure areas are included, however, there is still a statistically significant increase in childhood leukemias with proximity to the towers. In a letter to the American Journal of Epidemiology (1998, Am J Epidemiol 147(1):90-91), Hocking discussed the study by Dolk (1997, Am J Epidemiol 145:1-9, 1997 & 1997, Am J Epidemiol 145:10-17). While he states Dolk et al. did not find an excess of childhood type leukemia with residential proximity to towers, they did report a similar incidence rate ratio adult leukemia. Hocking et al. noted differences in the signals between the UK and Australian studies, including the UK transmissions in the UHF frequency range (430-890 MHz) which might couple less efficiently with the human body (by an order of magnitude) than Australian transmissions in the VHF range (63-215 MHz). Transmitting powers used in the UK are also 3-10 times higher than those used in Australia. Based on these and other differences, Hocking suggested the results of the UK and Australian studies complement rather than contradict each other. In reply, Dolk suggested that, while window effects might be possible, post hoc analysis from just the two studies did not provide strong evidence to support such a suggestion.

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