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Fig. 8 From (*1) Cellular Base Stations in Belo Horizonte

Strange Result No. 1

Dr. Richard Leonelli, a physicist from the Université de Montréal pointed out a strange result derived from Table 5 (*1).
Table 5 Cancer deaths according to cumulative distance from the base station

Dr. Leonelli points out that Table 5 reports that the relative risk of dying from cancer is 1.35 in the inner 100-meter ring when compared with the overall average. This is low enough to have at least some level of credibility, but high enough to cause concern. But this average includes the large population in the inner ring. What if we calculate the mortality in the inner ring and the outer rings separately and then compare the results?

If we look at the zone between 500 - 1000 meters, there is a population of 214,300 (
5) and 320 (6)deaths. This gives a mortality rate of 15 (7) in this zone. This gives a relative risk of 2.9 (8) for the inner 100 meter ring relative to the 500 - 1000 meter ring - which is big.

If we look at the zone between 800 - 1000 meters and carry out the same analysis, we find a mortality rate of 9 (
9). This is a relative risk of 4.8 (10) - which is enormous. This approximately 500% difference in the risk of death by cancer between the inner and outer zones is even bigger. The huge apparent difference in risk between the inner zone and the outer zones cannot be real.

If there were a causal association between cancer and proximity from a base station, these numbers would imply that RF emissions from base stations are actually a major cause of death for all types of cancers. As a consequence, cancer mortality rates should have increased markedly in the last decade, in parallel with the increasing number of base stations. This is not the case! For example, both cancer incidence and mortality have decreased in Canada in the last 15 years (*3 P40 & 41)). Thus, the huge apparent difference in risk between the inner zone and the outer zones cannot be real. Selection bias may be responsible for these lopsided numbers.

Strange Result No. 2

Another particularly strange result of this study is the distribution of the number of cancer deaths versus the duration of exposure (See Fig 16). This graph shows that the number of deaths peaked in the period of 1 - 2 years after a base station was installed, and mortality dropped steadily for each additional year of exposure. This result is contrary to what would be expected if base stations caused cancer. The number of cancer deaths should increase with time. In addition, it is well established that virtually all cancer types take many years to develop. There is no known carcinogen that could induce a wide spectrum of cancer types in such a short period. For example the latency to develop lung cancer from smoking is approximately 20 years. If it were true that exposure to EMF caused noticeable increases in cancer deaths after only two years, there would be vast zones of unpopulated land around every TV and FM transmitter, and in every urban area in the world. Again, this result calls into question the validity of the entire study.

Fig. 16 From *1 Cancer deaths vs. duration of exposure since first base station came into operation

Cell Phones

If cellular base stations were inducing cancer deaths in such a short period of time, then cell phones should be an even bigger cause of death. This is because the level of exposure to EMF from holding a cell phone next to the head is so many orders of magnitude larger (*2). The most common concern is that cell phones might cause brain cancer. Yet in the more than 15 years since cell phone use became common and widespread in the population, there has been no change in brain cancer incidence. One such study concluded that (*4): "Although there remains some uncertainty, the trend in the accumulating evidence is increasingly against the hypothesis that mobile phone use can cause brain tumours in adults."


Conclusion

The conclusion of the Brazilian study is that the risk of death from cancer is 1.35 for those living within proximity of 100 meters of a cellular phone base station compared to the average. This represents a roughly 35% increase in the risk - small enough to potentially have some credibility but large enough for concern. However, there are several important confounders that the authors failed to take into account in this study. There was no proper measurement of exposure. Selection bias skewed the results. Age distribution was not taken into account.

But two results undermine the credibility of the entire study. Close examination of the author's numbers reveals that the risk of death within 100 meters of a base station is approximately 500% higher than at a distance of 800 - 1000 meters. Such a huge difference cannot be real. Additionally the nonsensical result of 1 - 2 year cancer latency is a clear indication that the data used in this study is seriously flawed and that selection bias may be the cause. Furthermore, if the weak EMF from base stations was causing a noticeable increase in cancer deaths, there should be an even larger increase in cancer incidence and death with cell phones.

The World Health Organization (WHO) has published a Fact Sheet on base stations and wireless technologies (*5) "Considering the very low exposure levels and research results collected to date, there is no convincing scientific evidence that the weak RF signals from base stations and wireless networks cause adverse health effects."

Addendum

In re-examining the Brazilina cell phone base station study, Dr. Ken Foster came up with some additional observations concerning Fig 16 from the article. See Addendum.

Acknowledgements

I would like to thank Dr. Ken Foster of the Dept of Bioengineering at the University of Pennsylvania, and Dr. Richard Lionelli of the Dept of Physics at the University of Montreal for their invaluable suggestions and assistance in the preparation of this article.

Arithmetic calculations

1  Mathematical test of 6.4% age 70 - 79:
Relative deaths
Barreiro all age 20 - 29 percentage of deaths = 0.95
Central South
age 20 - 29 (1.0 - 0.064) = .936 of population
age 70 - 79 = 0.064 of population
Weighted percentage of deaths (1.0 - 0.064)*0.95 + 0.064*28 = 0.8892 + 1.792 = 2.68
Relative deaths South-Central/Barreiro  2.68/0.95 = 2.82
Relative deaths from Table 4:  5.83/2.05 = 2.84.
2  (22,493*100,000)/(2,238,332*11) = 91.3
3  12,094 - 7,191 = 4,903
4  22,493 - 12,094 = 10,399
5  2,148,327 - 1,934,032 = 214,295
6  7044 - 6724 = 320
7  320*10,000/214,300 = 15
8  43.42/15 = 2.9
9  (7044 - 6989)*10,000/(2,148,327 - 2,086,712) = 9
10  43.42/9 = 4.8

References

*1  Mortality by neoplasia and cellular telephone base stations in the Belo Horizonte municipality, Minas Gerais state, Brazil; Dode et al.; Science of the Total Environment 409 (2011) 3469 - 3665
*2  IARC Exposure Data: Radiofrequency Electromagnetic Fields: evalutation of cancer hazards
*3  Canadian Cancer Statistics 2011
*4 
Open access: Mobile Phones, Brain Tumors and the Interphone Study: Where Are We Now?; Swerdlow et al.; Environ Health Perspect; published online July 2011
*5 WHO Fact Sheet 304 Base Stations and Wireless Technologies
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