LNT: Effects of Cobalt-60 Exposure on Health of Taiwan Residents…

For reference, here is a Taiwan study of apartment residents exposed to cobalt-60 contaminated steel buildings. The study seems to support the thesis of radiation hormesis “It is an adaptive response of biological organisms to low levels of radiation stress or damage – a modest overcompensation to a disruption – resulting in improved fitness.” The Discussion section begins thusly:

The results of this study strongly suggest that whole- body chronic irradiation, in the dose rate range that the apartment residents received, caused no symptomatic adverse health effects, such as radiation sickness, or the increased cancer or increased congenital disease that are predicted by ICRP theories. On the contrary, those who were exposed had lower incidences of cancer mortality and congenital malformations.

UPDATE: Hank Roberts reports on a followup on that study discussed in a Mark Lynas comment. As I read this, the amended conclusion is no hormesis effect was demonstrated by this data set:

“Assuming the age and income distributions of these persons are the same as for the general population, it appears that significant beneficial health effects may be associated with this chronic radiation exposure”

I read a paper that adjusted for age and its conclusions show an increased risk, although they do not quantify it in a way to give me any clue as to how significant ‘significant’ is:

http://informahealthcare.com/doi/abs/10.1080/09553000601085980

“the biggest problem with the Taiwan study was that its findings were confounded by age differences. When the first analyses were conducted, the researchers did not have data on the ages of apartment residents. Thus, in describing their statistics, they explicitly noted that their conclusions are contingent on “assuming the exposed population has the same age distribution as the population of Taiwan”, an assumption they identify as “a critical factor.” However, subsequent studies of this case have shown that, in fact, the age demographic of apartment residents was much lower than that of the general Taiwanese population. On its own this would be expected to result in lower cancer rates. Accordingly, a more complete revised analysis was subsequently published in the International Journal of Radiation Biology. When age differences between apartment residents and the general Taiwanese population were finally controlled for, the data showed a significant dose-response effect whereby radiation exposure was associated with increased rates of cancer morbidity(disease, not death) among apartment residents compared to in the general population”

Over the age of 30, the residents did not show higher morbidity rates.

from paper:

Cancer risks in a population with prolonged low dose-rate γ-radiation exposure in radiocontaminated buildings, 1983 – 2002 2006, Vol. 82, No. 12 , Pages 849-858 (doi:10.1080/09553000601085980)

One thought on “LNT: Effects of Cobalt-60 Exposure on Health of Taiwan Residents…

  1. I note that you do not mention whether the dose response is higher than the LNT assumption or lower for the redone study. Any idea?? Assuming, of course, that there are no problems with this newer study.

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